diff options
| author | Mauro Carvalho Chehab <mchehab@redhat.com> | 2009-09-14 01:16:04 (GMT) |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2009-09-19 02:47:55 (GMT) |
| commit | 8e080c2e6cadada82a6b520e0c23a1cb974822d5 (patch) | |
| tree | 991450ff1abba98e5313906478c33816a202ccab /Documentation/DocBook/v4l | |
| parent | f4e96deb4513d044653027d4921fd7592195503a (diff) | |
| download | linux-8e080c2e6cadada82a6b520e0c23a1cb974822d5.tar.xz | |
V4L/DVB (12761): DocBook: add media API specs
The V4L and DVB API's are there for a long time. however, up to now,
no efforts were done to merge them to kernel DocBook.
This patch adds the current versions of the specs as an unique compendium.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/v4l')
106 files changed, 26795 insertions, 0 deletions
diff --git a/Documentation/DocBook/v4l/biblio.xml b/Documentation/DocBook/v4l/biblio.xml new file mode 100644 index 0000000..afc8a0d --- /dev/null +++ b/Documentation/DocBook/v4l/biblio.xml @@ -0,0 +1,188 @@ + <bibliography> + <title>References</title> + + <biblioentry id="eia608"> + <abbrev>EIA 608-B</abbrev> + <authorgroup> + <corpauthor>Electronic Industries Alliance (<ulink +url="http://www.eia.org">http://www.eia.org</ulink>)</corpauthor> + </authorgroup> + <title>EIA 608-B "Recommended Practice for Line 21 Data +Service"</title> + </biblioentry> + + <biblioentry id="en300294"> + <abbrev>EN 300 294</abbrev> + <authorgroup> + <corpauthor>European Telecommunication Standards Institute +(<ulink url="http://www.etsi.org">http://www.etsi.org</ulink>)</corpauthor> + </authorgroup> + <title>EN 300 294 "625-line television Wide Screen Signalling +(WSS)"</title> + </biblioentry> + + <biblioentry id="ets300231"> + <abbrev>ETS 300 231</abbrev> + <authorgroup> + <corpauthor>European Telecommunication Standards Institute +(<ulink +url="http://www.etsi.org">http://www.etsi.org</ulink>)</corpauthor> + </authorgroup> + <title>ETS 300 231 "Specification of the domestic video +Programme Delivery Control system (PDC)"</title> + </biblioentry> + + <biblioentry id="ets300706"> + <abbrev>ETS 300 706</abbrev> + <authorgroup> + <corpauthor>European Telecommunication Standards Institute +(<ulink url="http://www.etsi.org">http://www.etsi.org</ulink>)</corpauthor> + </authorgroup> + <title>ETS 300 706 "Enhanced Teletext specification"</title> + </biblioentry> + + <biblioentry id="mpeg2part1"> + <abbrev>ISO 13818-1</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>), International +Organisation for Standardisation (<ulink +url="http://www.iso.ch">http://www.iso.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-T Rec. H.222.0 | ISO/IEC 13818-1 "Information +technology — Generic coding of moving pictures and associated +audio information: Systems"</title> + </biblioentry> + + <biblioentry id="mpeg2part2"> + <abbrev>ISO 13818-2</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>), International +Organisation for Standardisation (<ulink +url="http://www.iso.ch">http://www.iso.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-T Rec. H.262 | ISO/IEC 13818-2 "Information +technology — Generic coding of moving pictures and associated +audio information: Video"</title> + </biblioentry> + + <biblioentry id="itu470"> + <abbrev>ITU BT.470</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.470-6 "Conventional Television +Systems"</title> + </biblioentry> + + <biblioentry id="itu601"> + <abbrev>ITU BT.601</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.601-5 "Studio Encoding Parameters +of Digital Television for Standard 4:3 and Wide-Screen 16:9 Aspect +Ratios"</title> + </biblioentry> + + <biblioentry id="itu653"> + <abbrev>ITU BT.653</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.653-3 "Teletext systems"</title> + </biblioentry> + + <biblioentry id="itu709"> + <abbrev>ITU BT.709</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.709-5 "Parameter values for the +HDTV standards for production and international programme +exchange"</title> + </biblioentry> + + <biblioentry id="itu1119"> + <abbrev>ITU BT.1119</abbrev> + <authorgroup> + <corpauthor>International Telecommunication Union (<ulink +url="http://www.itu.ch">http://www.itu.ch</ulink>)</corpauthor> + </authorgroup> + <title>ITU-R Recommendation BT.1119 "625-line +television Wide Screen Signalling (WSS)"</title> + </biblioentry> + + <biblioentry id="jfif"> + <abbrev>JFIF</abbrev> + <authorgroup> + <corpauthor>Independent JPEG Group (<ulink +url="http://www.ijg.org">http://www.ijg.org</ulink>)</corpauthor> + </authorgroup> + <title>JPEG File Interchange Format</title> + <subtitle>Version 1.02</subtitle> + </biblioentry> + + <biblioentry id="smpte12m"> + <abbrev>SMPTE 12M</abbrev> + <authorgroup> + <corpauthor>Society of Motion Picture and Television Engineers +(<ulink url="http://www.smpte.org">http://www.smpte.org</ulink>)</corpauthor> + </authorgroup> + <title>SMPTE 12M-1999 "Television, Audio and Film - Time and +Control Code"</title> + </biblioentry> + + <biblioentry id="smpte170m"> + <abbrev>SMPTE 170M</abbrev> + <authorgroup> + <corpauthor>Society of Motion Picture and Television Engineers +(<ulink url="http://www.smpte.org">http://www.smpte.org</ulink>)</corpauthor> + </authorgroup> + <title>SMPTE 170M-1999 "Television - Composite Analog Video +Signal - NTSC for Studio Applications"</title> + </biblioentry> + + <biblioentry id="smpte240m"> + <abbrev>SMPTE 240M</abbrev> + <authorgroup> + <corpauthor>Society of Motion Picture and Television Engineers +(<ulink url="http://www.smpte.org">http://www.smpte.org</ulink>)</corpauthor> + </authorgroup> + <title>SMPTE 240M-1999 "Television - Signal Parameters - +1125-Line High-Definition Production"</title> + </biblioentry> + + <biblioentry id="en50067"> + <abbrev>EN 50067</abbrev> + <authorgroup> + <corpauthor>European Committee for Electrotechnical Standardization +(<ulink url="http://www.cenelec.eu">http://www.cenelec.eu</ulink>)</corpauthor> + </authorgroup> + <title>Specification of the radio data system (RDS) for VHF/FM sound broadcasting +in the frequency range from 87,5 to 108,0 MHz</title> + </biblioentry> + + <biblioentry id="nrsc4"> + <abbrev>NRSC-4</abbrev> + <authorgroup> + <corpauthor>National Radio Systems Committee +(<ulink url="http://www.nrscstandards.org">http://www.nrscstandards.org</ulink>)</corpauthor> + </authorgroup> + <title>NTSC-4: United States RBDS Standard</title> + </biblioentry> + + </bibliography> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/capture.c.xml b/Documentation/DocBook/v4l/capture.c.xml new file mode 100644 index 0000000..acf46b6 --- /dev/null +++ b/Documentation/DocBook/v4l/capture.c.xml @@ -0,0 +1,659 @@ +<programlisting> +/* + * V4L2 video capture example + * + * This program can be used and distributed without restrictions. + * + * This program were got from V4L2 API, Draft 0.20 + * available at: http://v4l2spec.bytesex.org/ + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> + +#include <getopt.h> /* getopt_long() */ + +#include <fcntl.h> /* low-level i/o */ +#include <unistd.h> +#include <errno.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/mman.h> +#include <sys/ioctl.h> + +#include <linux/videodev2.h> + +#define CLEAR(x) memset(&(x), 0, sizeof(x)) + +enum io_method { + IO_METHOD_READ, + IO_METHOD_MMAP, + IO_METHOD_USERPTR, +}; + +struct buffer { + void *start; + size_t length; +}; + +static char *dev_name; +static enum io_method io = IO_METHOD_MMAP; +static int fd = -1; +struct buffer *buffers; +static unsigned int n_buffers; +static int out_buf; +static int force_format; +static int frame_count = 70; + +static void errno_exit(const char *s) +{ + fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno)); + exit(EXIT_FAILURE); +} + +static int xioctl(int fh, int request, void *arg) +{ + int r; + + do { + r = ioctl(fh, request, arg); + } while (-1 == r && EINTR == errno); + + return r; +} + +static void process_image(const void *p, int size) +{ + if (out_buf) + fwrite(p, size, 1, stdout); + + fflush(stderr); + fprintf(stderr, "."); + fflush(stdout); +} + +static int read_frame(void) +{ + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + unsigned int i; + + switch (io) { + case IO_METHOD_READ: + if (-1 == read(fd, buffers[0].start, buffers[0].length)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("read"); + } + } + + process_image(buffers[0].start, buffers[0].length); + break; + + case IO_METHOD_MMAP: + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + + if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("VIDIOC_DQBUF"); + } + } + + assert(buf.index < n_buffers); + + process_image(buffers[buf.index].start, buf.bytesused); + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + break; + + case IO_METHOD_USERPTR: + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_USERPTR; + + if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) { + switch (errno) { + case EAGAIN: + return 0; + + case EIO: + /* Could ignore EIO, see spec. */ + + /* fall through */ + + default: + errno_exit("VIDIOC_DQBUF"); + } + } + + for (i = 0; i < n_buffers; ++i) + if (buf.m.userptr == (unsigned long)buffers[i].start + && buf.length == buffers[i].length) + break; + + assert(i < n_buffers); + + process_image((void *)buf.m.userptr, buf.bytesused); + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + break; + } + + return 1; +} + +static void mainloop(void) +{ + unsigned int count; + + count = frame_count; + + while (count-- > 0) { + for (;;) { + fd_set fds; + struct timeval tv; + int r; + + FD_ZERO(&fds); + FD_SET(fd, &fds); + + /* Timeout. */ + tv.tv_sec = 2; + tv.tv_usec = 0; + + r = select(fd + 1, &fds, NULL, NULL, &tv); + + if (-1 == r) { + if (EINTR == errno) + continue; + errno_exit("select"); + } + + if (0 == r) { + fprintf(stderr, "select timeout\n"); + exit(EXIT_FAILURE); + } + + if (read_frame()) + break; + /* EAGAIN - continue select loop. */ + } + } +} + +static void stop_capturing(void) +{ + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + + switch (io) { + case IO_METHOD_READ: + /* Nothing to do. */ + break; + + case IO_METHOD_MMAP: + case IO_METHOD_USERPTR: + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type)) + errno_exit("VIDIOC_STREAMOFF"); + break; + } +} + +static void start_capturing(void) +{ + unsigned int i; + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + + switch (io) { + case IO_METHOD_READ: + /* Nothing to do. */ + break; + + case IO_METHOD_MMAP: + for (i = 0; i < n_buffers; ++i) { + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = i; + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) + errno_exit("VIDIOC_STREAMON"); + break; + + case IO_METHOD_USERPTR: + for (i = 0; i < n_buffers; ++i) { + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_USERPTR; + buf.index = i; + buf.m.userptr = (unsigned long)buffers[i].start; + buf.length = buffers[i].length; + + if (-1 == xioctl(fd, VIDIOC_QBUF, &buf)) + errno_exit("VIDIOC_QBUF"); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) + errno_exit("VIDIOC_STREAMON"); + break; + } +} + +static void uninit_device(void) +{ + unsigned int i; + + switch (io) { + case IO_METHOD_READ: + free(buffers[0].start); + break; + + case IO_METHOD_MMAP: + for (i = 0; i < n_buffers; ++i) + if (-1 == munmap(buffers[i].start, buffers[i].length)) + errno_exit("munmap"); + break; + + case IO_METHOD_USERPTR: + for (i = 0; i < n_buffers; ++i) + free(buffers[i].start); + break; + } + + free(buffers); +} + +static void init_read(unsigned int buffer_size) +{ + buffers = calloc(1, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + buffers[0].length = buffer_size; + buffers[0].start = malloc(buffer_size); + + if (!buffers[0].start) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } +} + +static void init_mmap(void) +{ + struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> req; + + CLEAR(req); + + req.count = 4; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_MMAP; + + if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) { + if (EINVAL == errno) { + fprintf(stderr, "%s does not support " + "memory mapping\n", dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_REQBUFS"); + } + } + + if (req.count < 2) { + fprintf(stderr, "Insufficient buffer memory on %s\n", + dev_name); + exit(EXIT_FAILURE); + } + + buffers = calloc(req.count, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = n_buffers; + + if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf)) + errno_exit("VIDIOC_QUERYBUF"); + + buffers[n_buffers].length = buf.length; + buffers[n_buffers].start = + mmap(NULL /* start anywhere */, + buf.length, + PROT_READ | PROT_WRITE /* required */, + MAP_SHARED /* recommended */, + fd, buf.m.offset); + + if (MAP_FAILED == buffers[n_buffers].start) + errno_exit("mmap"); + } +} + +static void init_userp(unsigned int buffer_size) +{ + struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> req; + + CLEAR(req); + + req.count = 4; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_USERPTR; + + if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) { + if (EINVAL == errno) { + fprintf(stderr, "%s does not support " + "user pointer i/o\n", dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_REQBUFS"); + } + } + + buffers = calloc(4, sizeof(*buffers)); + + if (!buffers) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + + for (n_buffers = 0; n_buffers < 4; ++n_buffers) { + buffers[n_buffers].length = buffer_size; + buffers[n_buffers].start = malloc(buffer_size); + + if (!buffers[n_buffers].start) { + fprintf(stderr, "Out of memory\n"); + exit(EXIT_FAILURE); + } + } +} + +static void init_device(void) +{ + struct <link linkend="v4l2-capability">v4l2_capability</link> cap; + struct <link linkend="v4l2-cropcap">v4l2_cropcap</link> cropcap; + struct <link linkend="v4l2-crop">v4l2_crop</link> crop; + struct <link linkend="v4l2-format">v4l2_format</link> fmt; + unsigned int min; + + if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) { + if (EINVAL == errno) { + fprintf(stderr, "%s is no V4L2 device\n", + dev_name); + exit(EXIT_FAILURE); + } else { + errno_exit("VIDIOC_QUERYCAP"); + } + } + + if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) { + fprintf(stderr, "%s is no video capture device\n", + dev_name); + exit(EXIT_FAILURE); + } + + switch (io) { + case IO_METHOD_READ: + if (!(cap.capabilities & V4L2_CAP_READWRITE)) { + fprintf(stderr, "%s does not support read i/o\n", + dev_name); + exit(EXIT_FAILURE); + } + break; + + case IO_METHOD_MMAP: + case IO_METHOD_USERPTR: + if (!(cap.capabilities & V4L2_CAP_STREAMING)) { + fprintf(stderr, "%s does not support streaming i/o\n", + dev_name); + exit(EXIT_FAILURE); + } + break; + } + + + /* Select video input, video standard and tune here. */ + + + CLEAR(cropcap); + + cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + + if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) { + crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + crop.c = cropcap.defrect; /* reset to default */ + + if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop)) { + switch (errno) { + case EINVAL: + /* Cropping not supported. */ + break; + default: + /* Errors ignored. */ + break; + } + } + } else { + /* Errors ignored. */ + } + + + CLEAR(fmt); + + fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + if (force_format) { + fmt.fmt.pix.width = 640; + fmt.fmt.pix.height = 480; + fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; + fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; + + if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt)) + errno_exit("VIDIOC_S_FMT"); + + /* Note VIDIOC_S_FMT may change width and height. */ + } else { + /* Preserve original settings as set by v4l2-ctl for example */ + if (-1 == xioctl(fd, VIDIOC_G_FMT, &fmt)) + errno_exit("VIDIOC_G_FMT"); + } + + /* Buggy driver paranoia. */ + min = fmt.fmt.pix.width * 2; + if (fmt.fmt.pix.bytesperline < min) + fmt.fmt.pix.bytesperline = min; + min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height; + if (fmt.fmt.pix.sizeimage < min) + fmt.fmt.pix.sizeimage = min; + + switch (io) { + case IO_METHOD_READ: + init_read(fmt.fmt.pix.sizeimage); + break; + + case IO_METHOD_MMAP: + init_mmap(); + break; + + case IO_METHOD_USERPTR: + init_userp(fmt.fmt.pix.sizeimage); + break; + } +} + +static void close_device(void) +{ + if (-1 == close(fd)) + errno_exit("close"); + + fd = -1; +} + +static void open_device(void) +{ + struct stat st; + + if (-1 == stat(dev_name, &st)) { + fprintf(stderr, "Cannot identify '%s': %d, %s\n", + dev_name, errno, strerror(errno)); + exit(EXIT_FAILURE); + } + + if (!S_ISCHR(st.st_mode)) { + fprintf(stderr, "%s is no device\n", dev_name); + exit(EXIT_FAILURE); + } + + fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, 0); + + if (-1 == fd) { + fprintf(stderr, "Cannot open '%s': %d, %s\n", + dev_name, errno, strerror(errno)); + exit(EXIT_FAILURE); + } +} + +static void usage(FILE *fp, int argc, char **argv) +{ + fprintf(fp, + "Usage: %s [options]\n\n" + "Version 1.3\n" + "Options:\n" + "-d | --device name Video device name [%s]\n" + "-h | --help Print this message\n" + "-m | --mmap Use memory mapped buffers [default]\n" + "-r | --read Use read() calls\n" + "-u | --userp Use application allocated buffers\n" + "-o | --output Outputs stream to stdout\n" + "-f | --format Force format to 640x480 YUYV\n" + "-c | --count Number of frames to grab [%i]\n" + "", + argv[0], dev_name, frame_count); +} + +static const char short_options[] = "d:hmruofc:"; + +static const struct option +long_options[] = { + { "device", required_argument, NULL, 'd' }, + { "help", no_argument, NULL, 'h' }, + { "mmap", no_argument, NULL, 'm' }, + { "read", no_argument, NULL, 'r' }, + { "userp", no_argument, NULL, 'u' }, + { "output", no_argument, NULL, 'o' }, + { "format", no_argument, NULL, 'f' }, + { "count", required_argument, NULL, 'c' }, + { 0, 0, 0, 0 } +}; + +int main(int argc, char **argv) +{ + dev_name = "/dev/video0"; + + for (;;) { + int idx; + int c; + + c = getopt_long(argc, argv, + short_options, long_options, &idx); + + if (-1 == c) + break; + + switch (c) { + case 0: /* getopt_long() flag */ + break; + + case 'd': + dev_name = optarg; + break; + + case 'h': + usage(stdout, argc, argv); + exit(EXIT_SUCCESS); + + case 'm': + io = IO_METHOD_MMAP; + break; + + case 'r': + io = IO_METHOD_READ; + break; + + case 'u': + io = IO_METHOD_USERPTR; + break; + + case 'o': + out_buf++; + break; + + case 'f': + force_format++; + break; + + case 'c': + errno = 0; + frame_count = strtol(optarg, NULL, 0); + if (errno) + errno_exit(optarg); + break; + + default: + usage(stderr, argc, argv); + exit(EXIT_FAILURE); + } + } + + open_device(); + init_device(); + start_capturing(); + mainloop(); + stop_capturing(); + uninit_device(); + close_device(); + fprintf(stderr, "\n"); + return 0; +} +</programlisting> diff --git a/Documentation/DocBook/v4l/common.xml b/Documentation/DocBook/v4l/common.xml new file mode 100644 index 0000000..dd598ac --- /dev/null +++ b/Documentation/DocBook/v4l/common.xml @@ -0,0 +1,1169 @@ + <title>Common API Elements</title> + + <para>Programming a V4L2 device consists of these +steps:</para> + + <itemizedlist> + <listitem> + <para>Opening the device</para> + </listitem> + <listitem> + <para>Changing device properties, selecting a video and audio +input, video standard, picture brightness a. o.</para> + </listitem> + <listitem> + <para>Negotiating a data format</para> + </listitem> + <listitem> + <para>Negotiating an input/output method</para> + </listitem> + <listitem> + <para>The actual input/output loop</para> + </listitem> + <listitem> + <para>Closing the device</para> + </listitem> + </itemizedlist> + + <para>In practice most steps are optional and can be executed out of +order. It depends on the V4L2 device type, you can read about the +details in <xref linkend="devices" />. In this chapter we will discuss +the basic concepts applicable to all devices.</para> + + <section id="open"> + <title>Opening and Closing Devices</title> + + <section> + <title>Device Naming</title> + + <para>V4L2 drivers are implemented as kernel modules, loaded +manually by the system administrator or automatically when a device is +first opened. The driver modules plug into the "videodev" kernel +module. It provides helper functions and a common application +interface specified in this document.</para> + + <para>Each driver thus loaded registers one or more device nodes +with major number 81 and a minor number between 0 and 255. Assigning +minor numbers to V4L2 devices is entirely up to the system administrator, +this is primarily intended to solve conflicts between devices.<footnote> + <para>Access permissions are associated with character +device special files, hence we must ensure device numbers cannot +change with the module load order. To this end minor numbers are no +longer automatically assigned by the "videodev" module as in V4L but +requested by the driver. The defaults will suffice for most people +unless two drivers compete for the same minor numbers.</para> + </footnote> The module options to select minor numbers are named +after the device special file with a "_nr" suffix. For example "video_nr" +for <filename>/dev/video</filename> video capture devices. The number is +an offset to the base minor number associated with the device type. +<footnote> + <para>In earlier versions of the V4L2 API the module options +where named after the device special file with a "unit_" prefix, expressing +the minor number itself, not an offset. Rationale for this change is unknown. +Lastly the naming and semantics are just a convention among driver writers, +the point to note is that minor numbers are not supposed to be hardcoded +into drivers.</para> + </footnote> When the driver supports multiple devices of the same +type more than one minor number can be assigned, separated by commas: +<informalexample> + <screen> +> insmod mydriver.o video_nr=0,1 radio_nr=0,1</screen> + </informalexample></para> + + <para>In <filename>/etc/modules.conf</filename> this may be +written as: <informalexample> + <screen> +alias char-major-81-0 mydriver +alias char-major-81-1 mydriver +alias char-major-81-64 mydriver <co id="alias" /> +options mydriver video_nr=0,1 radio_nr=0,1 <co id="options" /> + </screen> + <calloutlist> + <callout arearefs="alias"> + <para>When an application attempts to open a device +special file with major number 81 and minor number 0, 1, or 64, load +"mydriver" (and the "videodev" module it depends upon).</para> + </callout> + <callout arearefs="options"> + <para>Register the first two video capture devices with +minor number 0 and 1 (base number is 0), the first two radio device +with minor number 64 and 65 (base 64).</para> + </callout> + </calloutlist> + </informalexample> When no minor number is given as module +option the driver supplies a default. <xref linkend="devices" /> +recommends the base minor numbers to be used for the various device +types. Obviously minor numbers must be unique. When the number is +already in use the <emphasis>offending device</emphasis> will not be +registered. <!-- Blessed by Linus Torvalds on +linux-kernel@vger.kernel.org, 2002-11-20. --></para> + + <para>By convention system administrators create various +character device special files with these major and minor numbers in +the <filename>/dev</filename> directory. The names recomended for the +different V4L2 device types are listed in <xref linkend="devices" />. +</para> + + <para>The creation of character special files (with +<application>mknod</application>) is a privileged operation and +devices cannot be opened by major and minor number. That means +applications cannot <emphasis>reliable</emphasis> scan for loaded or +installed drivers. The user must enter a device name, or the +application can try the conventional device names.</para> + + <para>Under the device filesystem (devfs) the minor number +options are ignored. V4L2 drivers (or by proxy the "videodev" module) +automatically create the required device files in the +<filename>/dev/v4l</filename> directory using the conventional device +names above.</para> + </section> + + <section id="related"> + <title>Related Devices</title> + + <para>Devices can support several related functions. For example +video capturing, video overlay and VBI capturing are related because +these functions share, amongst other, the same video input and tuner +frequency. V4L and earlier versions of V4L2 used the same device name +and minor number for video capturing and overlay, but different ones +for VBI. Experience showed this approach has several problems<footnote> + <para>Given a device file name one cannot reliable find +related devices. For once names are arbitrary and in a system with +multiple devices, where only some support VBI capturing, a +<filename>/dev/video2</filename> is not necessarily related to +<filename>/dev/vbi2</filename>. The V4L +<constant>VIDIOCGUNIT</constant> ioctl would require a search for a +device file with a particular major and minor number.</para> + </footnote>, and to make things worse the V4L videodev module +used to prohibit multiple opens of a device.</para> + + <para>As a remedy the present version of the V4L2 API relaxed the +concept of device types with specific names and minor numbers. For +compatibility with old applications drivers must still register different +minor numbers to assign a default function to the device. But if related +functions are supported by the driver they must be available under all +registered minor numbers. The desired function can be selected after +opening the device as described in <xref linkend="devices" />.</para> + + <para>Imagine a driver supporting video capturing, video +overlay, raw VBI capturing, and FM radio reception. It registers three +devices with minor number 0, 64 and 224 (this numbering scheme is +inherited from the V4L API). Regardless if +<filename>/dev/video</filename> (81, 0) or +<filename>/dev/vbi</filename> (81, 224) is opened the application can +select any one of the video capturing, overlay or VBI capturing +functions. Without programming (e. g. reading from the device +with <application>dd</application> or <application>cat</application>) +<filename>/dev/video</filename> captures video images, while +<filename>/dev/vbi</filename> captures raw VBI data. +<filename>/dev/radio</filename> (81, 64) is invariable a radio device, +unrelated to the video functions. Being unrelated does not imply the +devices can be used at the same time, however. The &func-open; +function may very well return an &EBUSY;.</para> + + <para>Besides video input or output the hardware may also +support audio sampling or playback. If so, these functions are +implemented as OSS or ALSA PCM devices and eventually OSS or ALSA +audio mixer. The V4L2 API makes no provisions yet to find these +related devices. If you have an idea please write to the linux-media +mailing list: &v4l-ml;.</para> + </section> + + <section> + <title>Multiple Opens</title> + + <para>In general, V4L2 devices can be opened more than once. +When this is supported by the driver, users can for example start a +"panel" application to change controls like brightness or audio +volume, while another application captures video and audio. In other words, panel +applications are comparable to an OSS or ALSA audio mixer application. +When a device supports multiple functions like capturing and overlay +<emphasis>simultaneously</emphasis>, multiple opens allow concurrent +use of the device by forked processes or specialized applications.</para> + + <para>Multiple opens are optional, although drivers should +permit at least concurrent accesses without data exchange, &ie; panel +applications. This implies &func-open; can return an &EBUSY; when the +device is already in use, as well as &func-ioctl; functions initiating +data exchange (namely the &VIDIOC-S-FMT; ioctl), and the &func-read; +and &func-write; functions.</para> + + <para>Mere opening a V4L2 device does not grant exclusive +access.<footnote> + <para>Drivers could recognize the +<constant>O_EXCL</constant> open flag. Presently this is not required, +so applications cannot know if it really works.</para> + </footnote> Initiating data exchange however assigns the right +to read or write the requested type of data, and to change related +properties, to this file descriptor. Applications can request +additional access privileges using the priority mechanism described in +<xref linkend="app-pri" />.</para> + </section> + + <section> + <title>Shared Data Streams</title> + + <para>V4L2 drivers should not support multiple applications +reading or writing the same data stream on a device by copying +buffers, time multiplexing or similar means. This is better handled by +a proxy application in user space. When the driver supports stream +sharing anyway it must be implemented transparently. The V4L2 API does +not specify how conflicts are solved. <!-- For example O_EXCL when the +application does not want to be preempted, PROT_READ mmapped buffers +which can be mapped twice, what happens when image formats do not +match etc.--></para> + </section> + + <section> + <title>Functions</title> + + <para>To open and close V4L2 devices applications use the +&func-open; and &func-close; function, respectively. Devices are +programmed using the &func-ioctl; function as explained in the +following sections.</para> + </section> + </section> + + <section id="querycap"> + <title>Querying Capabilities</title> + + <para>Because V4L2 covers a wide variety of devices not all +aspects of the API are equally applicable to all types of devices. +Furthermore devices of the same type have different capabilities and +this specification permits the omission of a few complicated and less +important parts of the API.</para> + + <para>The &VIDIOC-QUERYCAP; ioctl is available to check if the kernel +device is compatible with this specification, and to query the <link +linkend="devices">functions</link> and <link linkend="io">I/O +methods</link> supported by the device. Other features can be queried +by calling the respective ioctl, for example &VIDIOC-ENUMINPUT; +to learn about the number, types and names of video connectors on the +device. Although abstraction is a major objective of this API, the +ioctl also allows driver specific applications to reliable identify +the driver.</para> + + <para>All V4L2 drivers must support +<constant>VIDIOC_QUERYCAP</constant>. Applications should always call +this ioctl after opening the device.</para> + </section> + + <section id="app-pri"> + <title>Application Priority</title> + + <para>When multiple applications share a device it may be +desirable to assign them different priorities. Contrary to the +traditional "rm -rf /" school of thought a video recording application +could for example block other applications from changing video +controls or switching the current TV channel. Another objective is to +permit low priority applications working in background, which can be +preempted by user controlled applications and automatically regain +control of the device at a later time.</para> + + <para>Since these features cannot be implemented entirely in user +space V4L2 defines the &VIDIOC-G-PRIORITY; and &VIDIOC-S-PRIORITY; +ioctls to request and query the access priority associate with a file +descriptor. Opening a device assigns a medium priority, compatible +with earlier versions of V4L2 and drivers not supporting these ioctls. +Applications requiring a different priority will usually call +<constant>VIDIOC_S_PRIORITY</constant> after verifying the device with +the &VIDIOC-QUERYCAP; ioctl.</para> + + <para>Ioctls changing driver properties, such as &VIDIOC-S-INPUT;, +return an &EBUSY; after another application obtained higher priority. +An event mechanism to notify applications about asynchronous property +changes has been proposed but not added yet.</para> + </section> + + <section id="video"> + <title>Video Inputs and Outputs</title> + + <para>Video inputs and outputs are physical connectors of a +device. These can be for example RF connectors (antenna/cable), CVBS +a.k.a. Composite Video, S-Video or RGB connectors. Only video and VBI +capture devices have inputs, output devices have outputs, at least one +each. Radio devices have no video inputs or outputs.</para> + + <para>To learn about the number and attributes of the +available inputs and outputs applications can enumerate them with the +&VIDIOC-ENUMINPUT; and &VIDIOC-ENUMOUTPUT; ioctl, respectively. The +&v4l2-input; returned by the <constant>VIDIOC_ENUMINPUT</constant> +ioctl also contains signal status information applicable when the +current video input is queried.</para> + + <para>The &VIDIOC-G-INPUT; and &VIDIOC-G-OUTPUT; ioctl return the +index of the current video input or output. To select a different +input or output applications call the &VIDIOC-S-INPUT; and +&VIDIOC-S-OUTPUT; ioctl. Drivers must implement all the input ioctls +when the device has one or more inputs, all the output ioctls when the +device has one or more outputs.</para> + + <!-- + <figure id=io-tree> + <title>Input and output enumeration is the root of most device properties.</title> + <mediaobject> + <imageobject> + <imagedata fileref="links.pdf" format="ps" /> + </imageobject> + <imageobject> + <imagedata fileref="links.gif" format="gif" /> + </imageobject> + <textobject> + <phrase>Links between various device property structures.</phrase> + </textobject> + </mediaobject> + </figure> + --> + + <example> + <title>Information about the current video input</title> + + <programlisting> +&v4l2-input; input; +int index; + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +memset (&input, 0, sizeof (input)); +input.index = index; + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUMINPUT"); + exit (EXIT_FAILURE); +} + +printf ("Current input: %s\n", input.name); + </programlisting> + </example> + + <example> + <title>Switching to the first video input</title> + + <programlisting> +int index; + +index = 0; + +if (-1 == ioctl (fd, &VIDIOC-S-INPUT;, &index)) { + perror ("VIDIOC_S_INPUT"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + </section> + + <section id="audio"> + <title>Audio Inputs and Outputs</title> + + <para>Audio inputs and outputs are physical connectors of a +device. Video capture devices have inputs, output devices have +outputs, zero or more each. Radio devices have no audio inputs or +outputs. They have exactly one tuner which in fact +<emphasis>is</emphasis> an audio source, but this API associates +tuners with video inputs or outputs only, and radio devices have +none of these.<footnote> + <para>Actually &v4l2-audio; ought to have a +<structfield>tuner</structfield> field like &v4l2-input;, not only +making the API more consistent but also permitting radio devices with +multiple tuners.</para> + </footnote> A connector on a TV card to loop back the received +audio signal to a sound card is not considered an audio output.</para> + + <para>Audio and video inputs and outputs are associated. Selecting +a video source also selects an audio source. This is most evident when +the video and audio source is a tuner. Further audio connectors can +combine with more than one video input or output. Assumed two +composite video inputs and two audio inputs exist, there may be up to +four valid combinations. The relation of video and audio connectors +is defined in the <structfield>audioset</structfield> field of the +respective &v4l2-input; or &v4l2-output;, where each bit represents +the index number, starting at zero, of one audio input or output.</para> + + <para>To learn about the number and attributes of the +available inputs and outputs applications can enumerate them with the +&VIDIOC-ENUMAUDIO; and &VIDIOC-ENUMAUDOUT; ioctl, respectively. The +&v4l2-audio; returned by the <constant>VIDIOC_ENUMAUDIO</constant> ioctl +also contains signal status information applicable when the current +audio input is queried.</para> + + <para>The &VIDIOC-G-AUDIO; and &VIDIOC-G-AUDOUT; ioctl report +the current audio input and output, respectively. Note that, unlike +&VIDIOC-G-INPUT; and &VIDIOC-G-OUTPUT; these ioctls return a structure +as <constant>VIDIOC_ENUMAUDIO</constant> and +<constant>VIDIOC_ENUMAUDOUT</constant> do, not just an index.</para> + + <para>To select an audio input and change its properties +applications call the &VIDIOC-S-AUDIO; ioctl. To select an audio +output (which presently has no changeable properties) applications +call the &VIDIOC-S-AUDOUT; ioctl.</para> + + <para>Drivers must implement all input ioctls when the device +has one or more inputs, all output ioctls when the device has one +or more outputs. When the device has any audio inputs or outputs the +driver must set the <constant>V4L2_CAP_AUDIO</constant> flag in the +&v4l2-capability; returned by the &VIDIOC-QUERYCAP; ioctl.</para> + + <example> + <title>Information about the current audio input</title> + + <programlisting> +&v4l2-audio; audio; + +memset (&audio, 0, sizeof (audio)); + +if (-1 == ioctl (fd, &VIDIOC-G-AUDIO;, &audio)) { + perror ("VIDIOC_G_AUDIO"); + exit (EXIT_FAILURE); +} + +printf ("Current input: %s\n", audio.name); + </programlisting> + </example> + + <example> + <title>Switching to the first audio input</title> + + <programlisting> +&v4l2-audio; audio; + +memset (&audio, 0, sizeof (audio)); /* clear audio.mode, audio.reserved */ + +audio.index = 0; + +if (-1 == ioctl (fd, &VIDIOC-S-AUDIO;, &audio)) { + perror ("VIDIOC_S_AUDIO"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + </section> + + <section id="tuner"> + <title>Tuners and Modulators</title> + + <section> + <title>Tuners</title> + + <para>Video input devices can have one or more tuners +demodulating a RF signal. Each tuner is associated with one or more +video inputs, depending on the number of RF connectors on the tuner. +The <structfield>type</structfield> field of the respective +&v4l2-input; returned by the &VIDIOC-ENUMINPUT; ioctl is set to +<constant>V4L2_INPUT_TYPE_TUNER</constant> and its +<structfield>tuner</structfield> field contains the index number of +the tuner.</para> + + <para>Radio devices have exactly one tuner with index zero, no +video inputs.</para> + + <para>To query and change tuner properties applications use the +&VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; ioctl, respectively. The +&v4l2-tuner; returned by <constant>VIDIOC_G_TUNER</constant> also +contains signal status information applicable when the tuner of the +current video input, or a radio tuner is queried. Note that +<constant>VIDIOC_S_TUNER</constant> does not switch the current tuner, +when there is more than one at all. The tuner is solely determined by +the current video input. Drivers must support both ioctls and set the +<constant>V4L2_CAP_TUNER</constant> flag in the &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl when the device has one or +more tuners.</para> + </section> + + <section> + <title>Modulators</title> + + <para>Video output devices can have one or more modulators, uh, +modulating a video signal for radiation or connection to the antenna +input of a TV set or video recorder. Each modulator is associated with +one or more video outputs, depending on the number of RF connectors on +the modulator. The <structfield>type</structfield> field of the +respective &v4l2-output; returned by the &VIDIOC-ENUMOUTPUT; ioctl is +set to <constant>V4L2_OUTPUT_TYPE_MODULATOR</constant> and its +<structfield>modulator</structfield> field contains the index number +of the modulator. This specification does not define radio output +devices.</para> + + <para>To query and change modulator properties applications use +the &VIDIOC-G-MODULATOR; and &VIDIOC-S-MODULATOR; ioctl. Note that +<constant>VIDIOC_S_MODULATOR</constant> does not switch the current +modulator, when there is more than one at all. The modulator is solely +determined by the current video output. Drivers must support both +ioctls and set the <constant>V4L2_CAP_MODULATOR</constant> flag in +the &v4l2-capability; returned by the &VIDIOC-QUERYCAP; ioctl when the +device has one or more modulators.</para> + </section> + + <section> + <title>Radio Frequency</title> + + <para>To get and set the tuner or modulator radio frequency +applications use the &VIDIOC-G-FREQUENCY; and &VIDIOC-S-FREQUENCY; +ioctl which both take a pointer to a &v4l2-frequency;. These ioctls +are used for TV and radio devices alike. Drivers must support both +ioctls when the tuner or modulator ioctls are supported, or +when the device is a radio device.</para> + </section> + + <section> + <title>Satellite Receivers</title> + + <para>To be discussed. See also <!-- private discussions of +Peter Schlaf, BD & MHS on 23 Jun 1999 ff., subject "v4l2 and satellit" and --> +proposals by Peter Schlaf, video4linux-list@redhat.com on 23 Oct 2002, +subject: "Re: [V4L] Re: v4l2 api".</para> + </section> + </section> + + <section id="standard"> + <title>Video Standards</title> + + <para>Video devices typically support one or more different video +standards or variations of standards. Each video input and output may +support another set of standards. This set is reported by the +<structfield>std</structfield> field of &v4l2-input; and +&v4l2-output; returned by the &VIDIOC-ENUMINPUT; and +&VIDIOC-ENUMOUTPUT; ioctl, respectively.</para> + + <para>V4L2 defines one bit for each analog video standard +currently in use worldwide, and sets aside bits for driver defined +standards, ⪚ hybrid standards to watch NTSC video tapes on PAL TVs +and vice versa. Applications can use the predefined bits to select a +particular standard, although presenting the user a menu of supported +standards is preferred. To enumerate and query the attributes of the +supported standards applications use the &VIDIOC-ENUMSTD; ioctl.</para> + + <para>Many of the defined standards are actually just variations +of a few major standards. The hardware may in fact not distinguish +between them, or do so internal and switch automatically. Therefore +enumerated standards also contain sets of one or more standard +bits.</para> + + <para>Assume a hypothetic tuner capable of demodulating B/PAL, +G/PAL and I/PAL signals. The first enumerated standard is a set of B +and G/PAL, switched automatically depending on the selected radio +frequency in UHF or VHF band. Enumeration gives a "PAL-B/G" or "PAL-I" +choice. Similar a Composite input may collapse standards, enumerating +"PAL-B/G/H/I", "NTSC-M" and "SECAM-D/K".<footnote> + <para>Some users are already confused by technical terms PAL, +NTSC and SECAM. There is no point asking them to distinguish between +B, G, D, or K when the software or hardware can do that +automatically.</para> + </footnote></para> + + <para>To query and select the standard used by the current video +input or output applications call the &VIDIOC-G-STD; and +&VIDIOC-S-STD; ioctl, respectively. The <emphasis>received</emphasis> +standard can be sensed with the &VIDIOC-QUERYSTD; ioctl. Note parameter of all these ioctls is a pointer to a &v4l2-std-id; type (a standard set), <emphasis>not</emphasis> an index into the standard enumeration.<footnote> + <para>An alternative to the current scheme is to use pointers +to indices as arguments of <constant>VIDIOC_G_STD</constant> and +<constant>VIDIOC_S_STD</constant>, the &v4l2-input; and +&v4l2-output; <structfield>std</structfield> field would be a set of +indices like <structfield>audioset</structfield>.</para> + <para>Indices are consistent with the rest of the API +and identify the standard unambiguously. In the present scheme of +things an enumerated standard is looked up by &v4l2-std-id;. Now the +standards supported by the inputs of a device can overlap. Just +assume the tuner and composite input in the example above both +exist on a device. An enumeration of "PAL-B/G", "PAL-H/I" suggests +a choice which does not exist. We cannot merge or omit sets, because +applications would be unable to find the standards reported by +<constant>VIDIOC_G_STD</constant>. That leaves separate enumerations +for each input. Also selecting a standard by &v4l2-std-id; can be +ambiguous. Advantage of this method is that applications need not +identify the standard indirectly, after enumerating.</para><para>So in +summary, the lookup itself is unavoidable. The difference is only +whether the lookup is necessary to find an enumerated standard or to +switch to a standard by &v4l2-std-id;.</para> + </footnote> Drivers must implement all video standard ioctls +when the device has one or more video inputs or outputs.</para> + + <para>Special rules apply to USB cameras where the notion of video +standards makes little sense. More generally any capture device, +output devices accordingly, which is <itemizedlist> + <listitem> + <para>incapable of capturing fields or frames at the nominal +rate of the video standard, or</para> + </listitem> + <listitem> + <para>where <link linkend="buffer">timestamps</link> refer +to the instant the field or frame was received by the driver, not the +capture time, or</para> + </listitem> + <listitem> + <para>where <link linkend="buffer">sequence numbers</link> +refer to the frames received by the driver, not the captured +frames.</para> + </listitem> + </itemizedlist> Here the driver shall set the +<structfield>std</structfield> field of &v4l2-input; and &v4l2-output; +to zero, the <constant>VIDIOC_G_STD</constant>, +<constant>VIDIOC_S_STD</constant>, +<constant>VIDIOC_QUERYSTD</constant> and +<constant>VIDIOC_ENUMSTD</constant> ioctls shall return the +&EINVAL;.<footnote> + <para>See <xref linkend="buffer" /> for a rationale. Probably +even USB cameras follow some well known video standard. It might have +been better to explicitly indicate elsewhere if a device cannot live +up to normal expectations, instead of this exception.</para> + </footnote></para> + + <example> + <title>Information about the current video standard</title> + + <programlisting> +&v4l2-std-id; std_id; +&v4l2-standard; standard; + +if (-1 == ioctl (fd, &VIDIOC-G-STD;, &std_id)) { + /* Note when VIDIOC_ENUMSTD always returns EINVAL this + is no video device or it falls under the USB exception, + and VIDIOC_G_STD returning EINVAL is no error. */ + + perror ("VIDIOC_G_STD"); + exit (EXIT_FAILURE); +} + +memset (&standard, 0, sizeof (standard)); +standard.index = 0; + +while (0 == ioctl (fd, &VIDIOC-ENUMSTD;, &standard)) { + if (standard.id & std_id) { + printf ("Current video standard: %s\n", standard.name); + exit (EXIT_SUCCESS); + } + + standard.index++; +} + +/* EINVAL indicates the end of the enumeration, which cannot be + empty unless this device falls under the USB exception. */ + +if (errno == EINVAL || standard.index == 0) { + perror ("VIDIOC_ENUMSTD"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <example> + <title>Listing the video standards supported by the current +input</title> + + <programlisting> +&v4l2-input; input; +&v4l2-standard; standard; + +memset (&input, 0, sizeof (input)); + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &input.index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUM_INPUT"); + exit (EXIT_FAILURE); +} + +printf ("Current input %s supports:\n", input.name); + +memset (&standard, 0, sizeof (standard)); +standard.index = 0; + +while (0 == ioctl (fd, &VIDIOC-ENUMSTD;, &standard)) { + if (standard.id & input.std) + printf ("%s\n", standard.name); + + standard.index++; +} + +/* EINVAL indicates the end of the enumeration, which cannot be + empty unless this device falls under the USB exception. */ + +if (errno != EINVAL || standard.index == 0) { + perror ("VIDIOC_ENUMSTD"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <example> + <title>Selecting a new video standard</title> + + <programlisting> +&v4l2-input; input; +&v4l2-std-id; std_id; + +memset (&input, 0, sizeof (input)); + +if (-1 == ioctl (fd, &VIDIOC-G-INPUT;, &input.index)) { + perror ("VIDIOC_G_INPUT"); + exit (EXIT_FAILURE); +} + +if (-1 == ioctl (fd, &VIDIOC-ENUMINPUT;, &input)) { + perror ("VIDIOC_ENUM_INPUT"); + exit (EXIT_FAILURE); +} + +if (0 == (input.std & V4L2_STD_PAL_BG)) { + fprintf (stderr, "Oops. B/G PAL is not supported.\n"); + exit (EXIT_FAILURE); +} + +/* Note this is also supposed to work when only B + <emphasis>or</emphasis> G/PAL is supported. */ + +std_id = V4L2_STD_PAL_BG; + +if (-1 == ioctl (fd, &VIDIOC-S-STD;, &std_id)) { + perror ("VIDIOC_S_STD"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + </section> + + &sub-controls; + + <section id="format"> + <title>Data Formats</title> + + <section> + <title>Data Format Negotiation</title> + + <para>Different devices exchange different kinds of data with +applications, for example video images, raw or sliced VBI data, RDS +datagrams. Even within one kind many different formats are possible, +in particular an abundance of image formats. Although drivers must +provide a default and the selection persists across closing and +reopening a device, applications should always negotiate a data format +before engaging in data exchange. Negotiation means the application +asks for a particular format and the driver selects and reports the +best the hardware can do to satisfy the request. Of course +applications can also just query the current selection.</para> + + <para>A single mechanism exists to negotiate all data formats +using the aggregate &v4l2-format; and the &VIDIOC-G-FMT; and +&VIDIOC-S-FMT; ioctls. Additionally the &VIDIOC-TRY-FMT; ioctl can be +used to examine what the hardware <emphasis>could</emphasis> do, +without actually selecting a new data format. The data formats +supported by the V4L2 API are covered in the respective device section +in <xref linkend="devices" />. For a closer look at image formats see +<xref linkend="pixfmt" />.</para> + + <para>The <constant>VIDIOC_S_FMT</constant> ioctl is a major +turning-point in the initialization sequence. Prior to this point +multiple panel applications can access the same device concurrently to +select the current input, change controls or modify other properties. +The first <constant>VIDIOC_S_FMT</constant> assigns a logical stream +(video data, VBI data etc.) exclusively to one file descriptor.</para> + + <para>Exclusive means no other application, more precisely no +other file descriptor, can grab this stream or change device +properties inconsistent with the negotiated parameters. A video +standard change for example, when the new standard uses a different +number of scan lines, can invalidate the selected image format. +Therefore only the file descriptor owning the stream can make +invalidating changes. Accordingly multiple file descriptors which +grabbed different logical streams prevent each other from interfering +with their settings. When for example video overlay is about to start +or already in progress, simultaneous video capturing may be restricted +to the same cropping and image size.</para> + + <para>When applications omit the +<constant>VIDIOC_S_FMT</constant> ioctl its locking side effects are +implied by the next step, the selection of an I/O method with the +&VIDIOC-REQBUFS; ioctl or implicit with the first &func-read; or +&func-write; call.</para> + + <para>Generally only one logical stream can be assigned to a +file descriptor, the exception being drivers permitting simultaneous +video capturing and overlay using the same file descriptor for +compatibility with V4L and earlier versions of V4L2. Switching the +logical stream or returning into "panel mode" is possible by closing +and reopening the device. Drivers <emphasis>may</emphasis> support a +switch using <constant>VIDIOC_S_FMT</constant>.</para> + + <para>All drivers exchanging data with +applications must support the <constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl. Implementation of the +<constant>VIDIOC_TRY_FMT</constant> is highly recommended but +optional.</para> + </section> + + <section> + <title>Image Format Enumeration</title> + + <para>Apart of the generic format negotiation functions +a special ioctl to enumerate all image formats supported by video +capture, overlay or output devices is available.<footnote> + <para>Enumerating formats an application has no a-priori +knowledge of (otherwise it could explicitely ask for them and need not +enumerate) seems useless, but there are applications serving as proxy +between drivers and the actual video applications for which this is +useful.</para> + </footnote></para> + + <para>The &VIDIOC-ENUM-FMT; ioctl must be supported +by all drivers exchanging image data with applications.</para> + + <important> + <para>Drivers are not supposed to convert image formats in +kernel space. They must enumerate only formats directly supported by +the hardware. If necessary driver writers should publish an example +conversion routine or library for integration into applications.</para> + </important> + </section> + </section> + + <section id="crop"> + <title>Image Cropping, Insertion and Scaling</title> + + <para>Some video capture devices can sample a subsection of the +picture and shrink or enlarge it to an image of arbitrary size. We +call these abilities cropping and scaling. Some video output devices +can scale an image up or down and insert it at an arbitrary scan line +and horizontal offset into a video signal.</para> + + <para>Applications can use the following API to select an area in +the video signal, query the default area and the hardware limits. +<emphasis>Despite their name, the &VIDIOC-CROPCAP;, &VIDIOC-G-CROP; +and &VIDIOC-S-CROP; ioctls apply to input as well as output +devices.</emphasis></para> + + <para>Scaling requires a source and a target. On a video capture +or overlay device the source is the video signal, and the cropping +ioctls determine the area actually sampled. The target are images +read by the application or overlaid onto the graphics screen. Their +size (and position for an overlay) is negotiated with the +&VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctls.</para> + + <para>On a video output device the source are the images passed in +by the application, and their size is again negotiated with the +<constant>VIDIOC_G/S_FMT</constant> ioctls, or may be encoded in a +compressed video stream. The target is the video signal, and the +cropping ioctls determine the area where the images are +inserted.</para> + + <para>Source and target rectangles are defined even if the device +does not support scaling or the <constant>VIDIOC_G/S_CROP</constant> +ioctls. Their size (and position where applicable) will be fixed in +this case. <emphasis>All capture and output device must support the +<constant>VIDIOC_CROPCAP</constant> ioctl such that applications can +determine if scaling takes place.</emphasis></para> + + <section> + <title>Cropping Structures</title> + + <figure id="crop-scale"> + <title>Image Cropping, Insertion and Scaling</title> + <mediaobject> + <imageobject> + <imagedata fileref="crop.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="crop.gif" format="GIF" /> + </imageobject> + <textobject> + <phrase>The cropping, insertion and scaling process</phrase> + </textobject> + </mediaobject> + </figure> + + <para>For capture devices the coordinates of the top left +corner, width and height of the area which can be sampled is given by +the <structfield>bounds</structfield> substructure of the +&v4l2-cropcap; returned by the <constant>VIDIOC_CROPCAP</constant> +ioctl. To support a wide range of hardware this specification does not +define an origin or units. However by convention drivers should +horizontally count unscaled samples relative to 0H (the leading edge +of the horizontal sync pulse, see <xref linkend="vbi-hsync" />). +Vertically ITU-R line +numbers of the first field (<xref linkend="vbi-525" />, <xref +linkend="vbi-625" />), multiplied by two if the driver can capture both +fields.</para> + + <para>The top left corner, width and height of the source +rectangle, that is the area actually sampled, is given by &v4l2-crop; +using the same coordinate system as &v4l2-cropcap;. Applications can +use the <constant>VIDIOC_G_CROP</constant> and +<constant>VIDIOC_S_CROP</constant> ioctls to get and set this +rectangle. It must lie completely within the capture boundaries and +the driver may further adjust the requested size and/or position +according to hardware limitations.</para> + + <para>Each capture device has a default source rectangle, given +by the <structfield>defrect</structfield> substructure of +&v4l2-cropcap;. The center of this rectangle shall align with the +center of the active picture area of the video signal, and cover what +the driver writer considers the complete picture. Drivers shall reset +the source rectangle to the default when the driver is first loaded, +but not later.</para> + + <para>For output devices these structures and ioctls are used +accordingly, defining the <emphasis>target</emphasis> rectangle where +the images will be inserted into the video signal.</para> + + </section> + + <section> + <title>Scaling Adjustments</title> + + <para>Video hardware can have various cropping, insertion and +scaling limitations. It may only scale up or down, support only +discrete scaling factors, or have different scaling abilities in +horizontal and vertical direction. Also it may not support scaling at +all. At the same time the &v4l2-crop; rectangle may have to be +aligned, and both the source and target rectangles may have arbitrary +upper and lower size limits. In particular the maximum +<structfield>width</structfield> and <structfield>height</structfield> +in &v4l2-crop; may be smaller than the +&v4l2-cropcap;.<structfield>bounds</structfield> area. Therefore, as +usual, drivers are expected to adjust the requested parameters and +return the actual values selected.</para> + + <para>Applications can change the source or the target rectangle +first, as they may prefer a particular image size or a certain area in +the video signal. If the driver has to adjust both to satisfy hardware +limitations, the last requested rectangle shall take priority, and the +driver should preferably adjust the opposite one. The &VIDIOC-TRY-FMT; +ioctl however shall not change the driver state and therefore only +adjust the requested rectangle.</para> + + <para>Suppose scaling on a video capture device is restricted to +a factor 1:1 or 2:1 in either direction and the target image size must +be a multiple of 16 × 16 pixels. The source cropping +rectangle is set to defaults, which are also the upper limit in this +example, of 640 × 400 pixels at offset 0, 0. An +application requests an image size of 300 × 225 +pixels, assuming video will be scaled down from the "full picture" +accordingly. The driver sets the image size to the closest possible +values 304 × 224, then chooses the cropping rectangle +closest to the requested size, that is 608 × 224 +(224 × 2:1 would exceed the limit 400). The offset +0, 0 is still valid, thus unmodified. Given the default cropping +rectangle reported by <constant>VIDIOC_CROPCAP</constant> the +application can easily propose another offset to center the cropping +rectangle.</para> + + <para>Now the application may insist on covering an area using a +picture aspect ratio closer to the original request, so it asks for a +cropping rectangle of 608 × 456 pixels. The present +scaling factors limit cropping to 640 × 384, so the +driver returns the cropping size 608 × 384 and adjusts +the image size to closest possible 304 × 192.</para> + + </section> + + <section> + <title>Examples</title> + + <para>Source and target rectangles shall remain unchanged across +closing and reopening a device, such that piping data into or out of a +device will work without special preparations. More advanced +applications should ensure the parameters are suitable before starting +I/O.</para> + + <example> + <title>Resetting the cropping parameters</title> + + <para>(A video capture device is assumed; change +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> for other +devices.)</para> + + <programlisting> +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); +crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +crop.c = cropcap.defrect; + +/* Ignore if cropping is not supported (EINVAL). */ + +if (-1 == ioctl (fd, &VIDIOC-S-CROP;, &crop) + && errno != EINVAL) { + perror ("VIDIOC_S_CROP"); + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <example> + <title>Simple downscaling</title> + + <para>(A video capture device is assumed.)</para> + + <programlisting> +&v4l2-cropcap; cropcap; +&v4l2-format; format; + +reset_cropping_parameters (); + +/* Scale down to 1/4 size of full picture. */ + +memset (&format, 0, sizeof (format)); /* defaults */ + +format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +format.fmt.pix.width = cropcap.defrect.width >> 1; +format.fmt.pix.height = cropcap.defrect.height >> 1; +format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; + +if (-1 == ioctl (fd, &VIDIOC-S-FMT;, &format)) { + perror ("VIDIOC_S_FORMAT"); + exit (EXIT_FAILURE); +} + +/* We could check the actual image size now, the actual scaling factor + or if the driver can scale at all. */ + </programlisting> + </example> + + <example> + <title>Selecting an output area</title> + + <programlisting> +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; + +if (-1 == ioctl (fd, VIDIOC_CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); + +crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT; +crop.c = cropcap.defrect; + +/* Scale the width and height to 50 % of their original size + and center the output. */ + +crop.c.width /= 2; +crop.c.height /= 2; +crop.c.left += crop.c.width / 2; +crop.c.top += crop.c.height / 2; + +/* Ignore if cropping is not supported (EINVAL). */ + +if (-1 == ioctl (fd, VIDIOC_S_CROP, &crop) + && errno != EINVAL) { + perror ("VIDIOC_S_CROP"); + exit (EXIT_FAILURE); +} +</programlisting> + </example> + + <example> + <title>Current scaling factor and pixel aspect</title> + + <para>(A video capture device is assumed.)</para> + + <programlisting> +&v4l2-cropcap; cropcap; +&v4l2-crop; crop; +&v4l2-format; format; +double hscale, vscale; +double aspect; +int dwidth, dheight; + +memset (&cropcap, 0, sizeof (cropcap)); +cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-CROPCAP;, &cropcap)) { + perror ("VIDIOC_CROPCAP"); + exit (EXIT_FAILURE); +} + +memset (&crop, 0, sizeof (crop)); +crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-G-CROP;, &crop)) { + if (errno != EINVAL) { + perror ("VIDIOC_G_CROP"); + exit (EXIT_FAILURE); + } + + /* Cropping not supported. */ + crop.c = cropcap.defrect; +} + +memset (&format, 0, sizeof (format)); +format.fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + +if (-1 == ioctl (fd, &VIDIOC-G-FMT;, &format)) { + perror ("VIDIOC_G_FMT"); + exit (EXIT_FAILURE); +} + +/* The scaling applied by the driver. */ + +hscale = format.fmt.pix.width / (double) crop.c.width; +vscale = format.fmt.pix.height / (double) crop.c.height; + +aspect = cropcap.pixelaspect.numerator / + (double) cropcap.pixelaspect.denominator; +aspect = aspect * hscale / vscale; + +/* Devices following ITU-R BT.601 do not capture + square pixels. For playback on a computer monitor + we should scale the images to this size. */ + +dwidth = format.fmt.pix.width / aspect; +dheight = format.fmt.pix.height; + </programlisting> + </example> + </section> + </section> + + <section id="streaming-par"> + <title>Streaming Parameters</title> + + <para>Streaming parameters are intended to optimize the video +capture process as well as I/O. Presently applications can request a +high quality capture mode with the &VIDIOC-S-PARM; ioctl.</para> + + <para>The current video standard determines a nominal number of +frames per second. If less than this number of frames is to be +captured or output, applications can request frame skipping or +duplicating on the driver side. This is especially useful when using +the &func-read; or &func-write;, which are not augmented by timestamps +or sequence counters, and to avoid unneccessary data copying.</para> + + <para>Finally these ioctls can be used to determine the number of +buffers used internally by a driver in read/write mode. For +implications see the section discussing the &func-read; +function.</para> + + <para>To get and set the streaming parameters applications call +the &VIDIOC-G-PARM; and &VIDIOC-S-PARM; ioctl, respectively. They take +a pointer to a &v4l2-streamparm;, which contains a union holding +separate parameters for input and output devices.</para> + + <para>These ioctls are optional, drivers need not implement +them. If so, they return the &EINVAL;.</para> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/compat.xml b/Documentation/DocBook/v4l/compat.xml new file mode 100644 index 0000000..4d1902a --- /dev/null +++ b/Documentation/DocBook/v4l/compat.xml @@ -0,0 +1,2457 @@ + <title>Changes</title> + + <para>The following chapters document the evolution of the V4L2 API, +errata or extensions. They are also intended to help application and +driver writers to port or update their code.</para> + + <section id="diff-v4l"> + <title>Differences between V4L and V4L2</title> + + <para>The Video For Linux API was first introduced in Linux 2.1 to +unify and replace various TV and radio device related interfaces, +developed independently by driver writers in prior years. Starting +with Linux 2.5 the much improved V4L2 API replaces the V4L API, +although existing drivers will continue to support V4L applications in +the future, either directly or through the V4L2 compatibility layer in +the <filename>videodev</filename> kernel module translating ioctls on +the fly. For a transition period not all drivers will support the V4L2 +API.</para> + + <section> + <title>Opening and Closing Devices</title> + + <para>For compatibility reasons the character device file names +recommended for V4L2 video capture, overlay, radio, teletext and raw +vbi capture devices did not change from those used by V4L. They are +listed in <xref linkend="devices" /> and below in <xref + linkend="v4l-dev" />.</para> + + <para>The V4L <filename>videodev</filename> module automatically +assigns minor numbers to drivers in load order, depending on the +registered device type. We recommend that V4L2 drivers by default +register devices with the same numbers, but the system administrator +can assign arbitrary minor numbers using driver module options. The +major device number remains 81.</para> + + <table id="v4l-dev"> + <title>V4L Device Types, Names and Numbers</title> + <tgroup cols="3"> + <thead> + <row> + <entry>Device Type</entry> + <entry>File Name</entry> + <entry>Minor Numbers</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry>Video capture and overlay</entry> + <entry><para><filename>/dev/video</filename> and +<filename>/dev/bttv0</filename><footnote> <para>According to +Documentation/devices.txt these should be symbolic links to +<filename>/dev/video0</filename>. Note the original bttv interface is +not compatible with V4L or V4L2.</para> </footnote>, +<filename>/dev/video0</filename> to +<filename>/dev/video63</filename></para></entry> + <entry>0-63</entry> + </row> + <row> + <entry>Radio receiver</entry> + <entry><para><filename>/dev/radio</filename><footnote> + <para>According to +<filename>Documentation/devices.txt</filename> a symbolic link to +<filename>/dev/radio0</filename>.</para> + </footnote>, <filename>/dev/radio0</filename> to +<filename>/dev/radio63</filename></para></entry> + <entry>64-127</entry> + </row> + <row> + <entry>Teletext decoder</entry> + <entry><para><filename>/dev/vtx</filename>, +<filename>/dev/vtx0</filename> to +<filename>/dev/vtx31</filename></para></entry> + <entry>192-223</entry> + </row> + <row> + <entry>Raw VBI capture</entry> + <entry><para><filename>/dev/vbi</filename>, +<filename>/dev/vbi0</filename> to +<filename>/dev/vbi31</filename></para></entry> + <entry>224-255</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>V4L prohibits (or used to prohibit) multiple opens of a +device file. V4L2 drivers <emphasis>may</emphasis> support multiple +opens, see <xref linkend="open" /> for details and consequences.</para> + + <para>V4L drivers respond to V4L2 ioctls with an &EINVAL;. The +compatibility layer in the V4L2 <filename>videodev</filename> module +can translate V4L ioctl requests to their V4L2 counterpart, however a +V4L2 driver usually needs more preparation to become fully V4L +compatible. This is covered in more detail in <xref + linkend="driver" />.</para> + </section> + + <section> + <title>Querying Capabilities</title> + + <para>The V4L <constant>VIDIOCGCAP</constant> ioctl is +equivalent to V4L2's &VIDIOC-QUERYCAP;.</para> + + <para>The <structfield>name</structfield> field in struct +<structname>video_capability</structname> became +<structfield>card</structfield> in &v4l2-capability;, +<structfield>type</structfield> was replaced by +<structfield>capabilities</structfield>. Note V4L2 does not +distinguish between device types like this, better think of basic +video input, video output and radio devices supporting a set of +related functions like video capturing, video overlay and VBI +capturing. See <xref linkend="open" /> for an +introduction.<informaltable> + <tgroup cols="3"> + <thead> + <row> + <entry>struct +<structname>video_capability</structname> +<structfield>type</structfield></entry> + <entry>&v4l2-capability; +<structfield>capabilities</structfield> flags</entry> + <entry>Purpose</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>VID_TYPE_CAPTURE</constant></entry> + <entry><constant>V4L2_CAP_VIDEO_CAPTURE</constant></entry> + <entry>The <link linkend="capture">video +capture</link> interface is supported.</entry> + </row> + <row> + <entry><constant>VID_TYPE_TUNER</constant></entry> + <entry><constant>V4L2_CAP_TUNER</constant></entry> + <entry>The device has a <link linkend="tuner">tuner or +modulator</link>.</entry> + </row> + <row> + <entry><constant>VID_TYPE_TELETEXT</constant></entry> + <entry><constant>V4L2_CAP_VBI_CAPTURE</constant></entry> + <entry>The <link linkend="raw-vbi">raw VBI +capture</link> interface is supported.</entry> + </row> + <row> + <entry><constant>VID_TYPE_OVERLAY</constant></entry> + <entry><constant>V4L2_CAP_VIDEO_OVERLAY</constant></entry> + <entry>The <link linkend="overlay">video +overlay</link> interface is supported.</entry> + </row> + <row> + <entry><constant>VID_TYPE_CHROMAKEY</constant></entry> + <entry><constant>V4L2_FBUF_CAP_CHROMAKEY</constant> in +field <structfield>capability</structfield> of +&v4l2-framebuffer;</entry> + <entry>Whether chromakey overlay is supported. For +more information on overlay see +<xref linkend="overlay" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_CLIPPING</constant></entry> + <entry><constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant> +and <constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant> in field +<structfield>capability</structfield> of &v4l2-framebuffer;</entry> + <entry>Whether clipping the overlaid image is +supported, see <xref linkend="overlay" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_FRAMERAM</constant></entry> + <entry><constant>V4L2_FBUF_CAP_EXTERNOVERLAY</constant> +<emphasis>not set</emphasis> in field +<structfield>capability</structfield> of &v4l2-framebuffer;</entry> + <entry>Whether overlay overwrites frame buffer memory, +see <xref linkend="overlay" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_SCALES</constant></entry> + <entry><constant>-</constant></entry> + <entry>This flag indicates if the hardware can scale +images. The V4L2 API implies the scale factor by setting the cropping +dimensions and image size with the &VIDIOC-S-CROP; and &VIDIOC-S-FMT; +ioctl, respectively. The driver returns the closest sizes possible. +For more information on cropping and scaling see <xref + linkend="crop" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MONOCHROME</constant></entry> + <entry><constant>-</constant></entry> + <entry>Applications can enumerate the supported image +formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device +supports grey scale capturing only. For more information on image +formats see <xref linkend="pixfmt" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_SUBCAPTURE</constant></entry> + <entry><constant>-</constant></entry> + <entry>Applications can call the &VIDIOC-G-CROP; ioctl +to determine if the device supports capturing a subsection of the full +picture ("cropping" in V4L2). If not, the ioctl returns the &EINVAL;. +For more information on cropping and scaling see <xref + linkend="crop" />.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MPEG_DECODER</constant></entry> + <entry><constant>-</constant></entry> + <entry>Applications can enumerate the supported image +formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device +supports MPEG streams.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MPEG_ENCODER</constant></entry> + <entry><constant>-</constant></entry> + <entry>See above.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MJPEG_DECODER</constant></entry> + <entry><constant>-</constant></entry> + <entry>See above.</entry> + </row> + <row> + <entry><constant>VID_TYPE_MJPEG_ENCODER</constant></entry> + <entry><constant>-</constant></entry> + <entry>See above.</entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>The <structfield>audios</structfield> field was replaced +by <structfield>capabilities</structfield> flag +<constant>V4L2_CAP_AUDIO</constant>, indicating +<emphasis>if</emphasis> the device has any audio inputs or outputs. To +determine their number applications can enumerate audio inputs with +the &VIDIOC-G-AUDIO; ioctl. The audio ioctls are described in <xref + linkend="audio" />.</para> + + <para>The <structfield>maxwidth</structfield>, +<structfield>maxheight</structfield>, +<structfield>minwidth</structfield> and +<structfield>minheight</structfield> fields were removed. Calling the +&VIDIOC-S-FMT; or &VIDIOC-TRY-FMT; ioctl with the desired dimensions +returns the closest size possible, taking into account the current +video standard, cropping and scaling limitations.</para> + </section> + + <section> + <title>Video Sources</title> + + <para>V4L provides the <constant>VIDIOCGCHAN</constant> and +<constant>VIDIOCSCHAN</constant> ioctl using struct +<structname>video_channel</structname> to enumerate +the video inputs of a V4L device. The equivalent V4L2 ioctls +are &VIDIOC-ENUMINPUT;, &VIDIOC-G-INPUT; and &VIDIOC-S-INPUT; +using &v4l2-input; as discussed in <xref linkend="video" />.</para> + + <para>The <structfield>channel</structfield> field counting +inputs was renamed to <structfield>index</structfield>, the video +input types were renamed as follows: <informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>struct <structname>video_channel</structname> +<structfield>type</structfield></entry> + <entry>&v4l2-input; +<structfield>type</structfield></entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>VIDEO_TYPE_TV</constant></entry> + <entry><constant>V4L2_INPUT_TYPE_TUNER</constant></entry> + </row> + <row> + <entry><constant>VIDEO_TYPE_CAMERA</constant></entry> + <entry><constant>V4L2_INPUT_TYPE_CAMERA</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>Unlike the <structfield>tuners</structfield> field +expressing the number of tuners of this input, V4L2 assumes each video +input is connected to at most one tuner. However a tuner can have more +than one input, &ie; RF connectors, and a device can have multiple +tuners. The index number of the tuner associated with the input, if +any, is stored in field <structfield>tuner</structfield> of +&v4l2-input;. Enumeration of tuners is discussed in <xref + linkend="tuner" />.</para> + + <para>The redundant <constant>VIDEO_VC_TUNER</constant> flag was +dropped. Video inputs associated with a tuner are of type +<constant>V4L2_INPUT_TYPE_TUNER</constant>. The +<constant>VIDEO_VC_AUDIO</constant> flag was replaced by the +<structfield>audioset</structfield> field. V4L2 considers devices with +up to 32 audio inputs. Each set bit in the +<structfield>audioset</structfield> field represents one audio input +this video input combines with. For information about audio inputs and +how to switch between them see <xref linkend="audio" />.</para> + + <para>The <structfield>norm</structfield> field describing the +supported video standards was replaced by +<structfield>std</structfield>. The V4L specification mentions a flag +<constant>VIDEO_VC_NORM</constant> indicating whether the standard can +be changed. This flag was a later addition together with the +<structfield>norm</structfield> field and has been removed in the +meantime. V4L2 has a similar, albeit more comprehensive approach +to video standards, see <xref linkend="standard" /> for more +information.</para> + </section> + + <section> + <title>Tuning</title> + + <para>The V4L <constant>VIDIOCGTUNER</constant> and +<constant>VIDIOCSTUNER</constant> ioctl and struct +<structname>video_tuner</structname> can be used to enumerate the +tuners of a V4L TV or radio device. The equivalent V4L2 ioctls are +&VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; using &v4l2-tuner;. Tuners are +covered in <xref linkend="tuner" />.</para> + + <para>The <structfield>tuner</structfield> field counting tuners +was renamed to <structfield>index</structfield>. The fields +<structfield>name</structfield>, <structfield>rangelow</structfield> +and <structfield>rangehigh</structfield> remained unchanged.</para> + + <para>The <constant>VIDEO_TUNER_PAL</constant>, +<constant>VIDEO_TUNER_NTSC</constant> and +<constant>VIDEO_TUNER_SECAM</constant> flags indicating the supported +video standards were dropped. This information is now contained in the +associated &v4l2-input;. No replacement exists for the +<constant>VIDEO_TUNER_NORM</constant> flag indicating whether the +video standard can be switched. The <structfield>mode</structfield> +field to select a different video standard was replaced by a whole new +set of ioctls and structures described in <xref linkend="standard" />. +Due to its ubiquity it should be mentioned the BTTV driver supports +several standards in addition to the regular +<constant>VIDEO_MODE_PAL</constant> (0), +<constant>VIDEO_MODE_NTSC</constant>, +<constant>VIDEO_MODE_SECAM</constant> and +<constant>VIDEO_MODE_AUTO</constant> (3). Namely N/PAL Argentina, +M/PAL, N/PAL, and NTSC Japan with numbers 3-6 (sic).</para> + + <para>The <constant>VIDEO_TUNER_STEREO_ON</constant> flag +indicating stereo reception became +<constant>V4L2_TUNER_SUB_STEREO</constant> in field +<structfield>rxsubchans</structfield>. This field also permits the +detection of monaural and bilingual audio, see the definition of +&v4l2-tuner; for details. Presently no replacement exists for the +<constant>VIDEO_TUNER_RDS_ON</constant> and +<constant>VIDEO_TUNER_MBS_ON</constant> flags.</para> + + <para> The <constant>VIDEO_TUNER_LOW</constant> flag was renamed +to <constant>V4L2_TUNER_CAP_LOW</constant> in the &v4l2-tuner; +<structfield>capability</structfield> field.</para> + + <para>The <constant>VIDIOCGFREQ</constant> and +<constant>VIDIOCSFREQ</constant> ioctl to change the tuner frequency +where renamed to &VIDIOC-G-FREQUENCY; and &VIDIOC-S-FREQUENCY;. They +take a pointer to a &v4l2-frequency; instead of an unsigned long +integer.</para> + </section> + + <section id="v4l-image-properties"> + <title>Image Properties</title> + + <para>V4L2 has no equivalent of the +<constant>VIDIOCGPICT</constant> and <constant>VIDIOCSPICT</constant> +ioctl and struct <structname>video_picture</structname>. The following +fields where replaced by V4L2 controls accessible with the +&VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls:<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>struct <structname>video_picture</structname></entry> + <entry>V4L2 Control ID</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><structfield>brightness</structfield></entry> + <entry><constant>V4L2_CID_BRIGHTNESS</constant></entry> + </row> + <row> + <entry><structfield>hue</structfield></entry> + <entry><constant>V4L2_CID_HUE</constant></entry> + </row> + <row> + <entry><structfield>colour</structfield></entry> + <entry><constant>V4L2_CID_SATURATION</constant></entry> + </row> + <row> + <entry><structfield>contrast</structfield></entry> + <entry><constant>V4L2_CID_CONTRAST</constant></entry> + </row> + <row> + <entry><structfield>whiteness</structfield></entry> + <entry><constant>V4L2_CID_WHITENESS</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>The V4L picture controls are assumed to range from 0 to +65535 with no particular reset value. The V4L2 API permits arbitrary +limits and defaults which can be queried with the &VIDIOC-QUERYCTRL; +ioctl. For general information about controls see <xref +linkend="control" />.</para> + + <para>The <structfield>depth</structfield> (average number of +bits per pixel) of a video image is implied by the selected image +format. V4L2 does not explicitely provide such information assuming +applications recognizing the format are aware of the image depth and +others need not know. The <structfield>palette</structfield> field +moved into the &v4l2-pix-format;:<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>struct <structname>video_picture</structname> +<structfield>palette</structfield></entry> + <entry>&v4l2-pix-format; +<structfield>pixfmt</structfield></entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>VIDEO_PALETTE_GREY</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-GREY"><constant>V4L2_PIX_FMT_GREY</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_HI240</constant></entry> + <entry><para><link +linkend="pixfmt-reserved"><constant>V4L2_PIX_FMT_HI240</constant></link><footnote> + <para>This is a custom format used by the BTTV +driver, not one of the V4L2 standard formats.</para> + </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RGB565</constant></entry> + <entry><para><link +linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_RGB565</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RGB555</constant></entry> + <entry><para><link +linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_RGB555</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RGB24</constant></entry> + <entry><para><link +linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_BGR24</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RGB32</constant></entry> + <entry><para><link +linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_BGR32</constant></link><footnote> + <para>Presumably all V4L RGB formats are +little-endian, although some drivers might interpret them according to machine endianess. V4L2 defines little-endian, big-endian and red/blue +swapped variants. For details see <xref linkend="pixfmt-rgb" />.</para> + </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV422</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link></para></entry> + </row> + <row> + <entry><para><constant>VIDEO_PALETTE_YUYV</constant><footnote> + <para><constant>VIDEO_PALETTE_YUV422</constant> +and <constant>VIDEO_PALETTE_YUYV</constant> are the same formats. Some +V4L drivers respond to one, some to the other.</para> + </footnote></para></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_UYVY</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-UYVY"><constant>V4L2_PIX_FMT_UYVY</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV420</constant></entry> + <entry>None</entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV411</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-Y41P"><constant>V4L2_PIX_FMT_Y41P</constant></link><footnote> + <para>Not to be confused with +<constant>V4L2_PIX_FMT_YUV411P</constant>, which is a planar +format.</para> </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_RAW</constant></entry> + <entry><para>None<footnote> <para>V4L explains this +as: "RAW capture (BT848)"</para> </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV422P</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YUV422P"><constant>V4L2_PIX_FMT_YUV422P</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV411P</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YUV411P"><constant>V4L2_PIX_FMT_YUV411P</constant></link><footnote> + <para>Not to be confused with +<constant>V4L2_PIX_FMT_Y41P</constant>, which is a packed +format.</para> </footnote></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV420P</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></link></para></entry> + </row> + <row> + <entry><constant>VIDEO_PALETTE_YUV410P</constant></entry> + <entry><para><link +linkend="V4L2-PIX-FMT-YVU410"><constant>V4L2_PIX_FMT_YVU410</constant></link></para></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>V4L2 image formats are defined in <xref +linkend="pixfmt" />. The image format can be selected with the +&VIDIOC-S-FMT; ioctl.</para> + </section> + + <section> + <title>Audio</title> + + <para>The <constant>VIDIOCGAUDIO</constant> and +<constant>VIDIOCSAUDIO</constant> ioctl and struct +<structname>video_audio</structname> are used to enumerate the +audio inputs of a V4L device. The equivalent V4L2 ioctls are +&VIDIOC-G-AUDIO; and &VIDIOC-S-AUDIO; using &v4l2-audio; as +discussed in <xref linkend="audio" />.</para> + + <para>The <structfield>audio</structfield> "channel number" +field counting audio inputs was renamed to +<structfield>index</structfield>.</para> + + <para>On <constant>VIDIOCSAUDIO</constant> the +<structfield>mode</structfield> field selects <emphasis>one</emphasis> +of the <constant>VIDEO_SOUND_MONO</constant>, +<constant>VIDEO_SOUND_STEREO</constant>, +<constant>VIDEO_SOUND_LANG1</constant> or +<constant>VIDEO_SOUND_LANG2</constant> audio demodulation modes. When +the current audio standard is BTSC +<constant>VIDEO_SOUND_LANG2</constant> refers to SAP and +<constant>VIDEO_SOUND_LANG1</constant> is meaningless. Also +undocumented in the V4L specification, there is no way to query the +selected mode. On <constant>VIDIOCGAUDIO</constant> the driver returns +the <emphasis>actually received</emphasis> audio programmes in this +field. In the V4L2 API this information is stored in the &v4l2-tuner; +<structfield>rxsubchans</structfield> and +<structfield>audmode</structfield> fields, respectively. See <xref +linkend="tuner" /> for more information on tuners. Related to audio +modes &v4l2-audio; also reports if this is a mono or stereo +input, regardless if the source is a tuner.</para> + + <para>The following fields where replaced by V4L2 controls +accessible with the &VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and +&VIDIOC-S-CTRL; ioctls:<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>struct +<structname>video_audio</structname></entry> + <entry>V4L2 Control ID</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><structfield>volume</structfield></entry> + <entry><constant>V4L2_CID_AUDIO_VOLUME</constant></entry> + </row> + <row> + <entry><structfield>bass</structfield></entry> + <entry><constant>V4L2_CID_AUDIO_BASS</constant></entry> + </row> + <row> + <entry><structfield>treble</structfield></entry> + <entry><constant>V4L2_CID_AUDIO_TREBLE</constant></entry> + </row> + <row> + <entry><structfield>balance</structfield></entry> + <entry><constant>V4L2_CID_AUDIO_BALANCE</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>To determine which of these controls are supported by a +driver V4L provides the <structfield>flags</structfield> +<constant>VIDEO_AUDIO_VOLUME</constant>, +<constant>VIDEO_AUDIO_BASS</constant>, +<constant>VIDEO_AUDIO_TREBLE</constant> and +<constant>VIDEO_AUDIO_BALANCE</constant>. In the V4L2 API the +&VIDIOC-QUERYCTRL; ioctl reports if the respective control is +supported. Accordingly the <constant>VIDEO_AUDIO_MUTABLE</constant> +and <constant>VIDEO_AUDIO_MUTE</constant> flags where replaced by the +boolean <constant>V4L2_CID_AUDIO_MUTE</constant> control.</para> + + <para>All V4L2 controls have a <structfield>step</structfield> +attribute replacing the struct <structname>video_audio</structname> +<structfield>step</structfield> field. The V4L audio controls are +assumed to range from 0 to 65535 with no particular reset value. The +V4L2 API permits arbitrary limits and defaults which can be queried +with the &VIDIOC-QUERYCTRL; ioctl. For general information about +controls see <xref linkend="control" />.</para> + </section> + + <section> + <title>Frame Buffer Overlay</title> + + <para>The V4L2 ioctls equivalent to +<constant>VIDIOCGFBUF</constant> and <constant>VIDIOCSFBUF</constant> +are &VIDIOC-G-FBUF; and &VIDIOC-S-FBUF;. The +<structfield>base</structfield> field of struct +<structname>video_buffer</structname> remained unchanged, except V4L2 +defines a flag to indicate non-destructive overlays instead of a +<constant>NULL</constant> pointer. All other fields moved into the +&v4l2-pix-format; <structfield>fmt</structfield> substructure of +&v4l2-framebuffer;. The <structfield>depth</structfield> field was +replaced by <structfield>pixelformat</structfield>. See <xref + linkend="pixfmt-rgb" /> for a list of RGB formats and their +respective color depths.</para> + + <para>Instead of the special ioctls +<constant>VIDIOCGWIN</constant> and <constant>VIDIOCSWIN</constant> +V4L2 uses the general-purpose data format negotiation ioctls +&VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a +&v4l2-format; as argument. Here the <structfield>win</structfield> +member of the <structfield>fmt</structfield> union is used, a +&v4l2-window;.</para> + + <para>The <structfield>x</structfield>, +<structfield>y</structfield>, <structfield>width</structfield> and +<structfield>height</structfield> fields of struct +<structname>video_window</structname> moved into &v4l2-rect; +substructure <structfield>w</structfield> of struct +<structname>v4l2_window</structname>. The +<structfield>chromakey</structfield>, +<structfield>clips</structfield>, and +<structfield>clipcount</structfield> fields remained unchanged. Struct +<structname>video_clip</structname> was renamed to &v4l2-clip;, also +containing a struct <structname>v4l2_rect</structname>, but the +semantics are still the same.</para> + + <para>The <constant>VIDEO_WINDOW_INTERLACE</constant> flag was +dropped. Instead applications must set the +<structfield>field</structfield> field to +<constant>V4L2_FIELD_ANY</constant> or +<constant>V4L2_FIELD_INTERLACED</constant>. The +<constant>VIDEO_WINDOW_CHROMAKEY</constant> flag moved into +&v4l2-framebuffer;, under the new name +<constant>V4L2_FBUF_FLAG_CHROMAKEY</constant>.</para> + + <para>In V4L, storing a bitmap pointer in +<structfield>clips</structfield> and setting +<structfield>clipcount</structfield> to +<constant>VIDEO_CLIP_BITMAP</constant> (-1) requests bitmap +clipping, using a fixed size bitmap of 1024 × 625 bits. Struct +<structname>v4l2_window</structname> has a separate +<structfield>bitmap</structfield> pointer field for this purpose and +the bitmap size is determined by <structfield>w.width</structfield> and +<structfield>w.height</structfield>.</para> + + <para>The <constant>VIDIOCCAPTURE</constant> ioctl to enable or +disable overlay was renamed to &VIDIOC-OVERLAY;.</para> + </section> + + <section> + <title>Cropping</title> + + <para>To capture only a subsection of the full picture V4L +defines the <constant>VIDIOCGCAPTURE</constant> and +<constant>VIDIOCSCAPTURE</constant> ioctls using struct +<structname>video_capture</structname>. The equivalent V4L2 ioctls are +&VIDIOC-G-CROP; and &VIDIOC-S-CROP; using &v4l2-crop;, and the related +&VIDIOC-CROPCAP; ioctl. This is a rather complex matter, see +<xref linkend="crop" /> for details.</para> + + <para>The <structfield>x</structfield>, +<structfield>y</structfield>, <structfield>width</structfield> and +<structfield>height</structfield> fields moved into &v4l2-rect; +substructure <structfield>c</structfield> of struct +<structname>v4l2_crop</structname>. The +<structfield>decimation</structfield> field was dropped. In the V4L2 +API the scaling factor is implied by the size of the cropping +rectangle and the size of the captured or overlaid image.</para> + + <para>The <constant>VIDEO_CAPTURE_ODD</constant> +and <constant>VIDEO_CAPTURE_EVEN</constant> flags to capture only the +odd or even field, respectively, were replaced by +<constant>V4L2_FIELD_TOP</constant> and +<constant>V4L2_FIELD_BOTTOM</constant> in the field named +<structfield>field</structfield> of &v4l2-pix-format; and +&v4l2-window;. These structures are used to select a capture or +overlay format with the &VIDIOC-S-FMT; ioctl.</para> + </section> + + <section> + <title>Reading Images, Memory Mapping</title> + + <section> + <title>Capturing using the read method</title> + + <para>There is no essential difference between reading images +from a V4L or V4L2 device using the &func-read; function, however V4L2 +drivers are not required to support this I/O method. Applications can +determine if the function is available with the &VIDIOC-QUERYCAP; +ioctl. All V4L2 devices exchanging data with applications must support +the &func-select; and &func-poll; functions.</para> + + <para>To select an image format and size, V4L provides the +<constant>VIDIOCSPICT</constant> and <constant>VIDIOCSWIN</constant> +ioctls. V4L2 uses the general-purpose data format negotiation ioctls +&VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a +&v4l2-format; as argument, here the &v4l2-pix-format; named +<structfield>pix</structfield> of its <structfield>fmt</structfield> +union is used.</para> + + <para>For more information about the V4L2 read interface see +<xref linkend="rw" />.</para> + </section> + <section> + <title>Capturing using memory mapping</title> + + <para>Applications can read from V4L devices by mapping +buffers in device memory, or more often just buffers allocated in +DMA-able system memory, into their address space. This avoids the data +copying overhead of the read method. V4L2 supports memory mapping as +well, with a few differences.</para> + + <informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>V4L</entry> + <entry>V4L2</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry></entry> + <entry>The image format must be selected before +buffers are allocated, with the &VIDIOC-S-FMT; ioctl. When no format +is selected the driver may use the last, possibly by another +application requested format.</entry> + </row> + <row> + <entry><para>Applications cannot change the number of +buffers. The it is built into the driver, unless it has a module +option to change the number when the driver module is +loaded.</para></entry> + <entry><para>The &VIDIOC-REQBUFS; ioctl allocates the +desired number of buffers, this is a required step in the initialization +sequence.</para></entry> + </row> + <row> + <entry><para>Drivers map all buffers as one contiguous +range of memory. The <constant>VIDIOCGMBUF</constant> ioctl is +available to query the number of buffers, the offset of each buffer +from the start of the virtual file, and the overall amount of memory +used, which can be used as arguments for the &func-mmap; +function.</para></entry> + <entry><para>Buffers are individually mapped. The +offset and size of each buffer can be determined with the +&VIDIOC-QUERYBUF; ioctl.</para></entry> + </row> + <row> + <entry><para>The <constant>VIDIOCMCAPTURE</constant> +ioctl prepares a buffer for capturing. It also determines the image +format for this buffer. The ioctl returns immediately, eventually with +an &EAGAIN; if no video signal had been detected. When the driver +supports more than one buffer applications can call the ioctl multiple +times and thus have multiple outstanding capture +requests.</para><para>The <constant>VIDIOCSYNC</constant> ioctl +suspends execution until a particular buffer has been +filled.</para></entry> + <entry><para>Drivers maintain an incoming and outgoing +queue. &VIDIOC-QBUF; enqueues any empty buffer into the incoming +queue. Filled buffers are dequeued from the outgoing queue with the +&VIDIOC-DQBUF; ioctl. To wait until filled buffers become available this +function, &func-select; or &func-poll; can be used. The +&VIDIOC-STREAMON; ioctl must be called once after enqueuing one or +more buffers to start capturing. Its counterpart +&VIDIOC-STREAMOFF; stops capturing and dequeues all buffers from both +queues. Applications can query the signal status, if known, with the +&VIDIOC-ENUMINPUT; ioctl.</para></entry> + </row> + </tbody> + </tgroup> + </informaltable> + + <para>For a more in-depth discussion of memory mapping and +examples, see <xref linkend="mmap" />.</para> + </section> + </section> + + <section> + <title>Reading Raw VBI Data</title> + + <para>Originally the V4L API did not specify a raw VBI capture +interface, only the device file <filename>/dev/vbi</filename> was +reserved for this purpose. The only driver supporting this interface +was the BTTV driver, de-facto defining the V4L VBI interface. Reading +from the device yields a raw VBI image with the following +parameters:<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>&v4l2-vbi-format;</entry> + <entry>V4L, BTTV driver</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry>sampling_rate</entry> + <entry>28636363 Hz NTSC (or any other 525-line +standard); 35468950 Hz PAL and SECAM (625-line standards)</entry> + </row> + <row> + <entry>offset</entry> + <entry>?</entry> + </row> + <row> + <entry>samples_per_line</entry> + <entry>2048</entry> + </row> + <row> + <entry>sample_format</entry> + <entry>V4L2_PIX_FMT_GREY. The last four bytes (a +machine endianess integer) contain a frame counter.</entry> + </row> + <row> + <entry>start[]</entry> + <entry>10, 273 NTSC; 22, 335 PAL and SECAM</entry> + </row> + <row> + <entry>count[]</entry> + <entry><para>16, 16<footnote><para>Old driver +versions used different values, eventually the custom +<constant>BTTV_VBISIZE</constant> ioctl was added to query the +correct values.</para></footnote></para></entry> + </row> + <row> + <entry>flags</entry> + <entry>0</entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>Undocumented in the V4L specification, in Linux 2.3 the +<constant>VIDIOCGVBIFMT</constant> and +<constant>VIDIOCSVBIFMT</constant> ioctls using struct +<structname>vbi_format</structname> were added to determine the VBI +image parameters. These ioctls are only partially compatible with the +V4L2 VBI interface specified in <xref linkend="raw-vbi" />.</para> + + <para>An <structfield>offset</structfield> field does not +exist, <structfield>sample_format</structfield> is supposed to be +<constant>VIDEO_PALETTE_RAW</constant>, equivalent to +<constant>V4L2_PIX_FMT_GREY</constant>. The remaining fields are +probably equivalent to &v4l2-vbi-format;.</para> + + <para>Apparently only the Zoran (ZR 36120) driver implements +these ioctls. The semantics differ from those specified for V4L2 in two +ways. The parameters are reset on &func-open; and +<constant>VIDIOCSVBIFMT</constant> always returns an &EINVAL; if the +parameters are invalid.</para> + </section> + + <section> + <title>Miscellaneous</title> + + <para>V4L2 has no equivalent of the +<constant>VIDIOCGUNIT</constant> ioctl. Applications can find the VBI +device associated with a video capture device (or vice versa) by +reopening the device and requesting VBI data. For details see +<xref linkend="open" />.</para> + + <para>No replacement exists for <constant>VIDIOCKEY</constant>, +and the V4L functions for microcode programming. A new interface for +MPEG compression and playback devices is documented in <xref + linkend="extended-controls" />.</para> + </section> + + </section> + + <section id="hist-v4l2"> + <title>Changes of the V4L2 API</title> + + <para>Soon after the V4L API was added to the kernel it was +criticised as too inflexible. In August 1998 Bill Dirks proposed a +number of improvements and began to work on documentation, example +drivers and applications. With the help of other volunteers this +eventually became the V4L2 API, not just an extension but a +replacement for the V4L API. However it took another four years and +two stable kernel releases until the new API was finally accepted for +inclusion into the kernel in its present form.</para> + + <section> + <title>Early Versions</title> + <para>1998-08-20: First version.</para> + + <para>1998-08-27: The &func-select; function was introduced.</para> + + <para>1998-09-10: New video standard interface.</para> + + <para>1998-09-18: The <constant>VIDIOC_NONCAP</constant> ioctl +was replaced by the otherwise meaningless <constant>O_TRUNC</constant> +&func-open; flag, and the aliases <constant>O_NONCAP</constant> and +<constant>O_NOIO</constant> were defined. Applications can set this +flag if they intend to access controls only, as opposed to capture +applications which need exclusive access. The +<constant>VIDEO_STD_XXX</constant> identifiers are now ordinals +instead of flags, and the <function>video_std_construct()</function> +helper function takes id and transmission arguments.</para> + + <para>1998-09-28: Revamped video standard. Made video controls +individually enumerable.</para> + + <para>1998-10-02: The <structfield>id</structfield> field was +removed from struct <structname>video_standard</structname> and the +color subcarrier fields were renamed. The &VIDIOC-QUERYSTD; ioctl was +renamed to &VIDIOC-ENUMSTD;, &VIDIOC-G-INPUT; to &VIDIOC-ENUMINPUT;. A +first draft of the Codec API was released.</para> + + <para>1998-11-08: Many minor changes. Most symbols have been +renamed. Some material changes to &v4l2-capability;.</para> + + <para>1998-11-12: The read/write directon of some ioctls was misdefined.</para> + + <para>1998-11-14: <constant>V4L2_PIX_FMT_RGB24</constant> +changed to <constant>V4L2_PIX_FMT_BGR24</constant>, and +<constant>V4L2_PIX_FMT_RGB32</constant> changed to +<constant>V4L2_PIX_FMT_BGR32</constant>. Audio controls are now +accessible with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls under +names starting with <constant>V4L2_CID_AUDIO</constant>. The +<constant>V4L2_MAJOR</constant> define was removed from +<filename>videodev.h</filename> since it was only used once in the +<filename>videodev</filename> kernel module. The +<constant>YUV422</constant> and <constant>YUV411</constant> planar +image formats were added.</para> + + <para>1998-11-28: A few ioctl symbols changed. Interfaces for codecs and +video output devices were added.</para> + + <para>1999-01-14: A raw VBI capture interface was added.</para> + + <para>1999-01-19: The <constant>VIDIOC_NEXTBUF</constant> ioctl + was removed.</para> + </section> + + <section> + <title>V4L2 Version 0.16 1999-01-31</title> + <para>1999-01-27: There is now one QBUF ioctl, VIDIOC_QWBUF and VIDIOC_QRBUF +are gone. VIDIOC_QBUF takes a v4l2_buffer as a parameter. Added +digital zoom (cropping) controls.</para> + </section> + + <!-- Where's 0.17? mhs couldn't find that videodev.h, perhaps Bill + forgot to bump the version number or never released it. --> + + <section> + <title>V4L2 Version 0.18 1999-03-16</title> + <para>Added a v4l to V4L2 ioctl compatibility layer to +videodev.c. Driver writers, this changes how you implement your ioctl +handler. See the Driver Writer's Guide. Added some more control id +codes.</para> + </section> + + <section> + <title>V4L2 Version 0.19 1999-06-05</title> + <para>1999-03-18: Fill in the category and catname fields of +v4l2_queryctrl objects before passing them to the driver. Required a +minor change to the VIDIOC_QUERYCTRL handlers in the sample +drivers.</para> + <para>1999-03-31: Better compatibility for v4l memory capture +ioctls. Requires changes to drivers to fully support new compatibility +features, see Driver Writer's Guide and v4l2cap.c. Added new control +IDs: V4L2_CID_HFLIP, _VFLIP. Changed V4L2_PIX_FMT_YUV422P to _YUV422P, +and _YUV411P to _YUV411P.</para> + <para>1999-04-04: Added a few more control IDs.</para> + <para>1999-04-07: Added the button control type.</para> + <para>1999-05-02: Fixed a typo in videodev.h, and added the +V4L2_CTRL_FLAG_GRAYED (later V4L2_CTRL_FLAG_GRABBED) flag.</para> + <para>1999-05-20: Definition of VIDIOC_G_CTRL was wrong causing +a malfunction of this ioctl.</para> + <para>1999-06-05: Changed the value of +V4L2_CID_WHITENESS.</para> + </section> + + <section> + <title>V4L2 Version 0.20 (1999-09-10)</title> + + <para>Version 0.20 introduced a number of changes which were +<emphasis>not backward compatible</emphasis> with 0.19 and earlier +versions. Purpose of these changes was to simplify the API, while +making it more extensible and following common Linux driver API +conventions.</para> + + <orderedlist> + <listitem> + <para>Some typos in <constant>V4L2_FMT_FLAG</constant> +symbols were fixed. &v4l2-clip; was changed for compatibility with +v4l. (1999-08-30)</para> + </listitem> + + <listitem> + <para><constant>V4L2_TUNER_SUB_LANG1</constant> was added. +(1999-09-05)</para> + </listitem> + + <listitem> + <para>All ioctl() commands that used an integer argument now +take a pointer to an integer. Where it makes sense, ioctls will return +the actual new value in the integer pointed to by the argument, a +common convention in the V4L2 API. The affected ioctls are: +VIDIOC_PREVIEW, VIDIOC_STREAMON, VIDIOC_STREAMOFF, VIDIOC_S_FREQ, +VIDIOC_S_INPUT, VIDIOC_S_OUTPUT, VIDIOC_S_EFFECT. For example +<programlisting> +err = ioctl (fd, VIDIOC_XXX, V4L2_XXX); +</programlisting> becomes <programlisting> +int a = V4L2_XXX; err = ioctl(fd, VIDIOC_XXX, &a); +</programlisting> + </para> + </listitem> + + <listitem> + <para>All the different get- and set-format commands were +swept into one &VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctl taking a union +and a type field selecting the union member as parameter. Purpose is to +simplify the API by eliminating several ioctls and to allow new and +driver private data streams without adding new ioctls.</para> + + <para>This change obsoletes the following ioctls: +<constant>VIDIOC_S_INFMT</constant>, +<constant>VIDIOC_G_INFMT</constant>, +<constant>VIDIOC_S_OUTFMT</constant>, +<constant>VIDIOC_G_OUTFMT</constant>, +<constant>VIDIOC_S_VBIFMT</constant> and +<constant>VIDIOC_G_VBIFMT</constant>. The image format structure +<structname>v4l2_format</structname> was renamed to &v4l2-pix-format;, +while &v4l2-format; is now the envelopping structure for all format +negotiations.</para> + </listitem> + + <listitem> + <para>Similar to the changes above, the +<constant>VIDIOC_G_PARM</constant> and +<constant>VIDIOC_S_PARM</constant> ioctls were merged with +<constant>VIDIOC_G_OUTPARM</constant> and +<constant>VIDIOC_S_OUTPARM</constant>. A +<structfield>type</structfield> field in the new &v4l2-streamparm; +selects the respective union member.</para> + + <para>This change obsoletes the +<constant>VIDIOC_G_OUTPARM</constant> and +<constant>VIDIOC_S_OUTPARM</constant> ioctls.</para> + </listitem> + + <listitem> + <para>Control enumeration was simplified, and two new +control flags were introduced and one dropped. The +<structfield>catname</structfield> field was replaced by a +<structfield>group</structfield> field.</para> + + <para>Drivers can now flag unsupported and temporarily +unavailable controls with <constant>V4L2_CTRL_FLAG_DISABLED</constant> +and <constant>V4L2_CTRL_FLAG_GRABBED</constant> respectively. The +<structfield>group</structfield> name indicates a possibly narrower +classification than the <structfield>category</structfield>. In other +words, there may be multiple groups within a category. Controls within +a group would typically be drawn within a group box. Controls in +different categories might have a greater separation, or may even +appear in separate windows.</para> + </listitem> + + <listitem> + <para>The &v4l2-buffer; <structfield>timestamp</structfield> +was changed to a 64 bit integer, containing the sampling or output +time of the frame in nanoseconds. Additionally timestamps will be in +absolute system time, not starting from zero at the beginning of a +stream. The data type name for timestamps is stamp_t, defined as a +signed 64-bit integer. Output devices should not send a buffer out +until the time in the timestamp field has arrived. I would like to +follow SGI's lead, and adopt a multimedia timestamping system like +their UST (Unadjusted System Time). See +http://reality.sgi.com/cpirazzi_engr/lg/time/intro.html. [This link is +no longer valid.] UST uses timestamps that are 64-bit signed integers +(not struct timeval's) and given in nanosecond units. The UST clock +starts at zero when the system is booted and runs continuously and +uniformly. It takes a little over 292 years for UST to overflow. There +is no way to set the UST clock. The regular Linux time-of-day clock +can be changed periodically, which would cause errors if it were being +used for timestamping a multimedia stream. A real UST style clock will +require some support in the kernel that is not there yet. But in +anticipation, I will change the timestamp field to a 64-bit integer, +and I will change the v4l2_masterclock_gettime() function (used only +by drivers) to return a 64-bit integer.</para> + </listitem> + + <listitem> + <para>A <structfield>sequence</structfield> field was added +to &v4l2-buffer;. The <structfield>sequence</structfield> field counts +captured frames, it is ignored by output devices. When a capture +driver drops a frame, the sequence number of that frame is +skipped.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 Version 0.20 incremental changes</title> + <!-- Version number didn't change anymore, reason unknown. --> + + <para>1999-12-23: In &v4l2-vbi-format; the +<structfield>reserved1</structfield> field became +<structfield>offset</structfield>. Previously drivers were required to +clear the <structfield>reserved1</structfield> field.</para> + + <para>2000-01-13: The + <constant>V4L2_FMT_FLAG_NOT_INTERLACED</constant> flag was added.</para> + + <para>2000-07-31: The <filename>linux/poll.h</filename> header +is now included by <filename>videodev.h</filename> for compatibility +with the original <filename>videodev.h</filename> file.</para> + + <para>2000-11-20: <constant>V4L2_TYPE_VBI_OUTPUT</constant> and +<constant>V4L2_PIX_FMT_Y41P</constant> were added.</para> + + <para>2000-11-25: <constant>V4L2_TYPE_VBI_INPUT</constant> was +added.</para> + + <para>2000-12-04: A couple typos in symbol names were fixed.</para> + + <para>2001-01-18: To avoid namespace conflicts the +<constant>fourcc</constant> macro defined in the +<filename>videodev.h</filename> header file was renamed to +<constant>v4l2_fourcc</constant>.</para> + + <para>2001-01-25: A possible driver-level compatibility problem +between the <filename>videodev.h</filename> file in Linux 2.4.0 and +the <filename>videodev.h</filename> file included in the +<filename>videodevX</filename> patch was fixed. Users of an earlier +version of <filename>videodevX</filename> on Linux 2.4.0 should +recompile their V4L and V4L2 drivers.</para> + + <para>2001-01-26: A possible kernel-level incompatibility +between the <filename>videodev.h</filename> file in the +<filename>videodevX</filename> patch and the +<filename>videodev.h</filename> file in Linux 2.2.x with devfs patches +applied was fixed.</para> + + <para>2001-03-02: Certain V4L ioctls which pass data in both +direction although they are defined with read-only parameter, did not +work correctly through the backward compatibility layer. +[Solution?]</para> + + <para>2001-04-13: Big endian 16-bit RGB formats were added.</para> + + <para>2001-09-17: New YUV formats and the &VIDIOC-G-FREQUENCY; and +&VIDIOC-S-FREQUENCY; ioctls were added. (The old +<constant>VIDIOC_G_FREQ</constant> and +<constant>VIDIOC_S_FREQ</constant> ioctls did not take multiple tuners +into account.)</para> + + <para>2000-09-18: <constant>V4L2_BUF_TYPE_VBI</constant> was +added. This may <emphasis>break compatibility</emphasis> as the +&VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctls may fail now if the struct +<structname>v4l2_fmt</structname> <structfield>type</structfield> +field does not contain <constant>V4L2_BUF_TYPE_VBI</constant>. In the +documentation of the &v4l2-vbi-format; +<structfield>offset</structfield> field the ambiguous phrase "rising +edge" was changed to "leading edge".</para> + </section> + + <section> + <title>V4L2 Version 0.20 2000-11-23</title> + + <para>A number of changes were made to the raw VBI +interface.</para> + + <orderedlist> + <listitem> + <para>Figures clarifying the line numbering scheme were +added to the V4L2 API specification. The +<structfield>start</structfield>[0] and +<structfield>start</structfield>[1] fields no longer count line +numbers beginning at zero. Rationale: a) The previous definition was +unclear. b) The <structfield>start</structfield>[] values are ordinal +numbers. c) There is no point in inventing a new line numbering +scheme. We now use line number as defined by ITU-R, period. +Compatibility: Add one to the start values. Applications depending on +the previous semantics may not function correctly.</para> + </listitem> + + <listitem> + <para>The restriction "count[0] > 0 and count[1] > 0" +has been relaxed to "(count[0] + count[1]) > 0". Rationale: +Drivers may allocate resources at scan line granularity and some data +services are transmitted only on the first field. The comment that +both <structfield>count</structfield> values will usually be equal is +misleading and pointless and has been removed. This change +<emphasis>breaks compatibility</emphasis> with earlier versions: +Drivers may return EINVAL, applications may not function +correctly.</para> + </listitem> + + <listitem> + <para>Drivers are again permitted to return negative +(unknown) start values as proposed earlier. Why this feature was +dropped is unclear. This change may <emphasis>break +compatibility</emphasis> with applications depending on the start +values being positive. The use of <constant>EBUSY</constant> and +<constant>EINVAL</constant> error codes with the &VIDIOC-S-FMT; ioctl +was clarified. The &EBUSY; was finally documented, and the +<structfield>reserved2</structfield> field which was previously +mentioned only in the <filename>videodev.h</filename> header +file.</para> + </listitem> + + <listitem> + <para>New buffer types +<constant>V4L2_TYPE_VBI_INPUT</constant> and +<constant>V4L2_TYPE_VBI_OUTPUT</constant> were added. The former is an +alias for the old <constant>V4L2_TYPE_VBI</constant>, the latter was +missing in the <filename>videodev.h</filename> file.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 Version 0.20 2002-07-25</title> + <para>Added sliced VBI interface proposal.</para> + </section> + + <section> + <title>V4L2 in Linux 2.5.46, 2002-10</title> + + <para>Around October-November 2002, prior to an announced +feature freeze of Linux 2.5, the API was revised, drawing from +experience with V4L2 0.20. This unnamed version was finally merged +into Linux 2.5.46.</para> + + <orderedlist> + <listitem> + <para>As specified in <xref linkend="related" />, drivers +must make related device functions available under all minor device +numbers.</para> + </listitem> + + <listitem> + <para>The &func-open; function requires access mode +<constant>O_RDWR</constant> regardless of the device type. All V4L2 +drivers exchanging data with applications must support the +<constant>O_NONBLOCK</constant> flag. The <constant>O_NOIO</constant> +flag, a V4L2 symbol which aliased the meaningless +<constant>O_TRUNC</constant> to indicate accesses without data +exchange (panel applications) was dropped. Drivers must stay in "panel +mode" until the application attempts to initiate a data exchange, see +<xref linkend="open" />.</para> + </listitem> + + <listitem> + <para>The &v4l2-capability; changed dramatically. Note that +also the size of the structure changed, which is encoded in the ioctl +request code, thus older V4L2 devices will respond with an &EINVAL; to +the new &VIDIOC-QUERYCAP; ioctl.</para> + + <para>There are new fields to identify the driver, a new RDS +device function <constant>V4L2_CAP_RDS_CAPTURE</constant>, the +<constant>V4L2_CAP_AUDIO</constant> flag indicates if the device has +any audio connectors, another I/O capability +<constant>V4L2_CAP_ASYNCIO</constant> can be flagged. In response to +these changes the <structfield>type</structfield> field became a bit +set and was merged into the <structfield>flags</structfield> field. +<constant>V4L2_FLAG_TUNER</constant> was renamed to +<constant>V4L2_CAP_TUNER</constant>, +<constant>V4L2_CAP_VIDEO_OVERLAY</constant> replaced +<constant>V4L2_FLAG_PREVIEW</constant> and +<constant>V4L2_CAP_VBI_CAPTURE</constant> and +<constant>V4L2_CAP_VBI_OUTPUT</constant> replaced +<constant>V4L2_FLAG_DATA_SERVICE</constant>. +<constant>V4L2_FLAG_READ</constant> and +<constant>V4L2_FLAG_WRITE</constant> were merged into +<constant>V4L2_CAP_READWRITE</constant>.</para> + + <para>The redundant fields +<structfield>inputs</structfield>, <structfield>outputs</structfield> +and <structfield>audios</structfield> were removed. These properties +can be determined as described in <xref linkend="video" /> and <xref +linkend="audio" />.</para> + + <para>The somewhat volatile and therefore barely useful +fields <structfield>maxwidth</structfield>, +<structfield>maxheight</structfield>, +<structfield>minwidth</structfield>, +<structfield>minheight</structfield>, +<structfield>maxframerate</structfield> were removed. This information +is available as described in <xref linkend="format" /> and +<xref linkend="standard" />.</para> + + <para><constant>V4L2_FLAG_SELECT</constant> was removed. We +believe the select() function is important enough to require support +of it in all V4L2 drivers exchanging data with applications. The +redundant <constant>V4L2_FLAG_MONOCHROME</constant> flag was removed, +this information is available as described in <xref + linkend="format" />.</para> + </listitem> + + <listitem> + <para>In &v4l2-input; the +<structfield>assoc_audio</structfield> field and the +<structfield>capability</structfield> field and its only flag +<constant>V4L2_INPUT_CAP_AUDIO</constant> was replaced by the new +<structfield>audioset</structfield> field. Instead of linking one +video input to one audio input this field reports all audio inputs +this video input combines with.</para> + + <para>New fields are <structfield>tuner</structfield> +(reversing the former link from tuners to video inputs), +<structfield>std</structfield> and +<structfield>status</structfield>.</para> + + <para>Accordingly &v4l2-output; lost its +<structfield>capability</structfield> and +<structfield>assoc_audio</structfield> fields. +<structfield>audioset</structfield>, +<structfield>modulator</structfield> and +<structfield>std</structfield> where added instead.</para> + </listitem> + + <listitem> + <para>The &v4l2-audio; field +<structfield>audio</structfield> was renamed to +<structfield>index</structfield>, for consistency with other +structures. A new capability flag +<constant>V4L2_AUDCAP_STEREO</constant> was added to indicated if the +audio input in question supports stereo sound. +<constant>V4L2_AUDCAP_EFFECTS</constant> and the corresponding +<constant>V4L2_AUDMODE</constant> flags where removed. This can be +easily implemented using controls. (However the same applies to AVL +which is still there.)</para> + + <para>Again for consistency the &v4l2-audioout; field +<structfield>audio</structfield> was renamed to +<structfield>index</structfield>.</para> + </listitem> + + <listitem> + <para>The &v4l2-tuner; +<structfield>input</structfield> field was replaced by an +<structfield>index</structfield> field, permitting devices with +multiple tuners. The link between video inputs and tuners is now +reversed, inputs point to their tuner. The +<structfield>std</structfield> substructure became a +simple set (more about this below) and moved into &v4l2-input;. A +<structfield>type</structfield> field was added.</para> + + <para>Accordingly in &v4l2-modulator; the +<structfield>output</structfield> was replaced by an +<structfield>index</structfield> field.</para> + + <para>In &v4l2-frequency; the +<structfield>port</structfield> field was replaced by a +<structfield>tuner</structfield> field containing the respective tuner +or modulator index number. A tuner <structfield>type</structfield> +field was added and the <structfield>reserved</structfield> field +became larger for future extensions (satellite tuners in +particular).</para> + </listitem> + + <listitem> + <para>The idea of completely transparent video standards was +dropped. Experience showed that applications must be able to work with +video standards beyond presenting the user a menu. Instead of +enumerating supported standards with an ioctl applications can now +refer to standards by &v4l2-std-id; and symbols defined in the +<filename>videodev2.h</filename> header file. For details see <xref + linkend="standard" />. The &VIDIOC-G-STD; and +&VIDIOC-S-STD; now take a pointer to this type as argument. +&VIDIOC-QUERYSTD; was added to autodetect the received standard, if +the hardware has this capability. In &v4l2-standard; an +<structfield>index</structfield> field was added for &VIDIOC-ENUMSTD;. +A &v4l2-std-id; field named <structfield>id</structfield> was added as +machine readable identifier, also replacing the +<structfield>transmission</structfield> field. The misleading +<structfield>framerate</structfield> field was renamed +to <structfield>frameperiod</structfield>. The now obsolete +<structfield>colorstandard</structfield> information, originally +needed to distguish between variations of standards, were +removed.</para> + + <para>Struct <structname>v4l2_enumstd</structname> ceased to +be. &VIDIOC-ENUMSTD; now takes a pointer to a &v4l2-standard; +directly. The information which standards are supported by a +particular video input or output moved into &v4l2-input; and +&v4l2-output; fields named <structfield>std</structfield>, +respectively.</para> + </listitem> + + <listitem> + <para>The &v4l2-queryctrl; fields +<structfield>category</structfield> and +<structfield>group</structfield> did not catch on and/or were not +implemented as expected and therefore removed.</para> + </listitem> + + <listitem> + <para>The &VIDIOC-TRY-FMT; ioctl was added to negotiate data +formats as with &VIDIOC-S-FMT;, but without the overhead of +programming the hardware and regardless of I/O in progress.</para> + + <para>In &v4l2-format; the <structfield>fmt</structfield> +union was extended to contain &v4l2-window;. All image format +negotiations are now possible with <constant>VIDIOC_G_FMT</constant>, +<constant>VIDIOC_S_FMT</constant> and +<constant>VIDIOC_TRY_FMT</constant>; ioctl. The +<constant>VIDIOC_G_WIN</constant> and +<constant>VIDIOC_S_WIN</constant> ioctls to prepare for a video +overlay were removed. The <structfield>type</structfield> field +changed to type &v4l2-buf-type; and the buffer type names changed as +follows.<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>Old defines</entry> + <entry>&v4l2-buf-type;</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_BUF_TYPE_CAPTURE</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant></entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_CODECIN</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_CODECOUT</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_EFFECTSIN</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_EFFECTSIN2</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_EFFECTSOUT</constant></entry> + <entry>Omitted for now</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEOOUT</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VBI_CAPTURE</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant></entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_PRIVATE_BASE</constant></entry> + <entry><constant>V4L2_BUF_TYPE_PRIVATE</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + </listitem> + + <listitem> + <para>In &v4l2-fmtdesc; a &v4l2-buf-type; field named +<structfield>type</structfield> was added as in &v4l2-format;. The +<constant>VIDIOC_ENUM_FBUFFMT</constant> ioctl is no longer needed and +was removed. These calls can be replaced by &VIDIOC-ENUM-FMT; with +type <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para> + </listitem> + + <listitem> + <para>In &v4l2-pix-format; the +<structfield>depth</structfield> field was removed, assuming +applications which recognize the format by its four-character-code +already know the color depth, and others do not care about it. The +same rationale lead to the removal of the +<constant>V4L2_FMT_FLAG_COMPRESSED</constant> flag. The +<constant>V4L2_FMT_FLAG_SWCONVECOMPRESSED</constant> flag was removed +because drivers are not supposed to convert images in kernel space. A +user library of conversion functions should be provided instead. The +<constant>V4L2_FMT_FLAG_BYTESPERLINE</constant> flag was redundant. +Applications can set the <structfield>bytesperline</structfield> field +to zero to get a reasonable default. Since the remaining flags were +replaced as well, the <structfield>flags</structfield> field itself +was removed.</para> + <para>The interlace flags were replaced by a &v4l2-field; +value in a newly added <structfield>field</structfield> +field.<informaltable> + <tgroup cols="2"> + <thead> + <row> + <entry>Old flag</entry> + <entry>&v4l2-field;</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_FMT_FLAG_NOT_INTERLACED</constant></entry> + <entry>?</entry> + </row> + <row> + <entry><constant>V4L2_FMT_FLAG_INTERLACED</constant> += <constant>V4L2_FMT_FLAG_COMBINED</constant></entry> + <entry><constant>V4L2_FIELD_INTERLACED</constant></entry> + </row> + <row> + <entry><constant>V4L2_FMT_FLAG_TOPFIELD</constant> += <constant>V4L2_FMT_FLAG_ODDFIELD</constant></entry> + <entry><constant>V4L2_FIELD_TOP</constant></entry> + </row> + <row> + <entry><constant>V4L2_FMT_FLAG_BOTFIELD</constant> += <constant>V4L2_FMT_FLAG_EVENFIELD</constant></entry> + <entry><constant>V4L2_FIELD_BOTTOM</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_FIELD_SEQ_TB</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_FIELD_SEQ_BT</constant></entry> + </row> + <row> + <entry><constant>-</constant></entry> + <entry><constant>V4L2_FIELD_ALTERNATE</constant></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + + <para>The color space flags were replaced by a +&v4l2-colorspace; value in a newly added +<structfield>colorspace</structfield> field, where one of +<constant>V4L2_COLORSPACE_SMPTE170M</constant>, +<constant>V4L2_COLORSPACE_BT878</constant>, +<constant>V4L2_COLORSPACE_470_SYSTEM_M</constant> or +<constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant> replaces +<constant>V4L2_FMT_CS_601YUV</constant>.</para> + </listitem> + + <listitem> + <para>In &v4l2-requestbuffers; the +<structfield>type</structfield> field was properly defined as +&v4l2-buf-type;. Buffer types changed as mentioned above. A new +<structfield>memory</structfield> field of type &v4l2-memory; was +added to distinguish between I/O methods using buffers allocated +by the driver or the application. See <xref linkend="io" /> for +details.</para> + </listitem> + + <listitem> + <para>In &v4l2-buffer; the <structfield>type</structfield> +field was properly defined as &v4l2-buf-type;. Buffer types changed as +mentioned above. A <structfield>field</structfield> field of type +&v4l2-field; was added to indicate if a buffer contains a top or +bottom field. The old field flags were removed. Since no unadjusted +system time clock was added to the kernel as planned, the +<structfield>timestamp</structfield> field changed back from type +stamp_t, an unsigned 64 bit integer expressing the sample time in +nanoseconds, to struct <structname>timeval</structname>. With the +addition of a second memory mapping method the +<structfield>offset</structfield> field moved into union +<structfield>m</structfield>, and a new +<structfield>memory</structfield> field of type &v4l2-memory; was +added to distinguish between I/O methods. See <xref linkend="io" /> +for details.</para> + + <para>The <constant>V4L2_BUF_REQ_CONTIG</constant> +flag was used by the V4L compatibility layer, after changes to this +code it was no longer needed. The +<constant>V4L2_BUF_ATTR_DEVICEMEM</constant> flag would indicate if +the buffer was indeed allocated in device memory rather than DMA-able +system memory. It was barely useful and so was removed.</para> + </listitem> + + <listitem> + <para>In &v4l2-framebuffer; the +<structfield>base[3]</structfield> array anticipating double- and +triple-buffering in off-screen video memory, however without defining +a synchronization mechanism, was replaced by a single pointer. The +<constant>V4L2_FBUF_CAP_SCALEUP</constant> and +<constant>V4L2_FBUF_CAP_SCALEDOWN</constant> flags were removed. +Applications can determine this capability more accurately using the +new cropping and scaling interface. The +<constant>V4L2_FBUF_CAP_CLIPPING</constant> flag was replaced by +<constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant> and +<constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant>.</para> + </listitem> + + <listitem> + <para>In &v4l2-clip; the <structfield>x</structfield>, +<structfield>y</structfield>, <structfield>width</structfield> and +<structfield>height</structfield> field moved into a +<structfield>c</structfield> substructure of type &v4l2-rect;. The +<structfield>x</structfield> and <structfield>y</structfield> fields +were renamed to <structfield>left</structfield> and +<structfield>top</structfield>, &ie; offsets to a context dependent +origin.</para> + </listitem> + + <listitem> + <para>In &v4l2-window; the <structfield>x</structfield>, +<structfield>y</structfield>, <structfield>width</structfield> and +<structfield>height</structfield> field moved into a +<structfield>w</structfield> substructure as above. A +<structfield>field</structfield> field of type %v4l2-field; was added +to distinguish between field and frame (interlaced) overlay.</para> + </listitem> + + <listitem> + <para>The digital zoom interface, including struct +<structname>v4l2_zoomcap</structname>, struct +<structname>v4l2_zoom</structname>, +<constant>V4L2_ZOOM_NONCAP</constant> and +<constant>V4L2_ZOOM_WHILESTREAMING</constant> was replaced by a new +cropping and scaling interface. The previously unused struct +<structname>v4l2_cropcap</structname> and +<structname>v4l2_crop</structname> where redefined for this purpose. +See <xref linkend="crop" /> for details.</para> + </listitem> + + <listitem> + <para>In &v4l2-vbi-format; the +<structfield>SAMPLE_FORMAT</structfield> field now contains a +four-character-code as used to identify video image formats and +<constant>V4L2_PIX_FMT_GREY</constant> replaces the +<constant>V4L2_VBI_SF_UBYTE</constant> define. The +<structfield>reserved</structfield> field was extended.</para> + </listitem> + + <listitem> + <para>In &v4l2-captureparm; the type of the +<structfield>timeperframe</structfield> field changed from unsigned +long to &v4l2-fract;. This allows the accurate expression of multiples +of the NTSC-M frame rate 30000 / 1001. A new field +<structfield>readbuffers</structfield> was added to control the driver +behaviour in read I/O mode.</para> + + <para>Similar changes were made to &v4l2-outputparm;.</para> + </listitem> + + <listitem> + <para>The struct <structname>v4l2_performance</structname> +and <constant>VIDIOC_G_PERF</constant> ioctl were dropped. Except when +using the <link linkend="rw">read/write I/O method</link>, which is +limited anyway, this information is already available to +applications.</para> + </listitem> + + <listitem> + <para>The example transformation from RGB to YCbCr color +space in the old V4L2 documentation was inaccurate, this has been +corrected in <xref linkend="pixfmt" />.<!-- 0.5670G should be +0.587, and 127/112 != 255/224 --></para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 2003-06-19</title> + + <orderedlist> + <listitem> + <para>A new capability flag +<constant>V4L2_CAP_RADIO</constant> was added for radio devices. Prior +to this change radio devices would identify solely by having exactly one +tuner whose type field reads <constant>V4L2_TUNER_RADIO</constant>.</para> + </listitem> + + <listitem> + <para>An optional driver access priority mechanism was +added, see <xref linkend="app-pri" /> for details.</para> + </listitem> + + <listitem> + <para>The audio input and output interface was found to be +incomplete.</para> + <para>Previously the &VIDIOC-G-AUDIO; +ioctl would enumerate the available audio inputs. An ioctl to +determine the current audio input, if more than one combines with the +current video input, did not exist. So +<constant>VIDIOC_G_AUDIO</constant> was renamed to +<constant>VIDIOC_G_AUDIO_OLD</constant>, this ioctl will be removed in +the future. The &VIDIOC-ENUMAUDIO; ioctl was added to enumerate +audio inputs, while &VIDIOC-G-AUDIO; now reports the current audio +input.</para> + <para>The same changes were made to &VIDIOC-G-AUDOUT; and +&VIDIOC-ENUMAUDOUT;.</para> + <para>Until further the "videodev" module will automatically +translate between the old and new ioctls, but drivers and applications +must be updated to successfully compile again.</para> + </listitem> + + <listitem> + <para>The &VIDIOC-OVERLAY; ioctl was incorrectly defined with +write-read parameter. It was changed to write-only, while the write-read +version was renamed to <constant>VIDIOC_OVERLAY_OLD</constant>. The old +ioctl will be removed in the future. Until further the "videodev" +kernel module will automatically translate to the new version, so drivers +must be recompiled, but not applications.</para> + </listitem> + + <listitem> + <para><xref linkend="overlay" /> incorrectly stated that +clipping rectangles define regions where the video can be seen. +Correct is that clipping rectangles define regions where +<emphasis>no</emphasis> video shall be displayed and so the graphics +surface can be seen.</para> + </listitem> + + <listitem> + <para>The &VIDIOC-S-PARM; and &VIDIOC-S-CTRL; ioctls were +defined with write-only parameter, inconsistent with other ioctls +modifying their argument. They were changed to write-read, while a +<constant>_OLD</constant> suffix was added to the write-only versions. +The old ioctls will be removed in the future. Drivers and +applications assuming a constant parameter need an update.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 2003-11-05</title> + <orderedlist> + <listitem> + <para>In <xref linkend="pixfmt-rgb" /> the following pixel +formats were incorrectly transferred from Bill Dirks' V4L2 +specification. Descriptions below refer to bytes in memory, in +ascending address order.<informaltable> + <tgroup cols="3"> + <thead> + <row> + <entry>Symbol</entry> + <entry>In this document prior to revision +0.5</entry> + <entry>Corrected</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_PIX_FMT_RGB24</constant></entry> + <entry>B, G, R</entry> + <entry>R, G, B</entry> + </row> + <row> + <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry> + <entry>R, G, B</entry> + <entry>B, G, R</entry> + </row> + <row> + <entry><constant>V4L2_PIX_FMT_RGB32</constant></entry> + <entry>B, G, R, X</entry> + <entry>R, G, B, X</entry> + </row> + <row> + <entry><constant>V4L2_PIX_FMT_BGR32</constant></entry> + <entry>R, G, B, X</entry> + <entry>B, G, R, X</entry> + </row> + </tbody> + </tgroup> + </informaltable> The +<constant>V4L2_PIX_FMT_BGR24</constant> example was always +correct.</para> + <para>In <xref linkend="v4l-image-properties" /> the mapping +of the V4L <constant>VIDEO_PALETTE_RGB24</constant> and +<constant>VIDEO_PALETTE_RGB32</constant> formats to V4L2 pixel formats +was accordingly corrected.</para> + </listitem> + + <listitem> + <para>Unrelated to the fixes above, drivers may still +interpret some V4L2 RGB pixel formats differently. These issues have +yet to be addressed, for details see <xref + linkend="pixfmt-rgb" />.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.6, 2004-05-09</title> + <orderedlist> + <listitem> + <para>The &VIDIOC-CROPCAP; ioctl was incorrectly defined +with read-only parameter. It is now defined as write-read ioctl, while +the read-only version was renamed to +<constant>VIDIOC_CROPCAP_OLD</constant>. The old ioctl will be removed +in the future.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.8</title> + <orderedlist> + <listitem> + <para>A new field <structfield>input</structfield> (former +<structfield>reserved[0]</structfield>) was added to the &v4l2-buffer; +structure. Purpose of this field is to alternate between video inputs +(⪚ cameras) in step with the video capturing process. This function +must be enabled with the new <constant>V4L2_BUF_FLAG_INPUT</constant> +flag. The <structfield>flags</structfield> field is no longer +read-only.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2004-08-01</title> + + <orderedlist> + <listitem> + <para>The return value of the +<xref linkend="func-open" /> function was incorrectly documented.</para> + </listitem> + + <listitem> + <para>Audio output ioctls end in -AUDOUT, not -AUDIOOUT.</para> + </listitem> + + <listitem> + <para>In the Current Audio Input example the +<constant>VIDIOC_G_AUDIO</constant> ioctl took the wrong +argument.</para> + </listitem> + + <listitem> + <para>The documentation of the &VIDIOC-QBUF; and +&VIDIOC-DQBUF; ioctls did not mention the &v4l2-buffer; +<structfield>memory</structfield> field. It was also missing from +examples. Also on the <constant>VIDIOC_DQBUF</constant> page the &EIO; +was not documented.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.14</title> + <orderedlist> + <listitem> + <para>A new sliced VBI interface was added. It is documented +in <xref linkend="sliced" /> and replaces the interface first +proposed in V4L2 specification 0.8.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.15</title> + <orderedlist> + <listitem> + <para>The &VIDIOC-LOG-STATUS; ioctl was added.</para> + </listitem> + + <listitem> + <para>New video standards +<constant>V4L2_STD_NTSC_443</constant>, +<constant>V4L2_STD_SECAM_LC</constant>, +<constant>V4L2_STD_SECAM_DK</constant> (a set of SECAM D, K and K1), +and <constant>V4L2_STD_ATSC</constant> (a set of +<constant>V4L2_STD_ATSC_8_VSB</constant> and +<constant>V4L2_STD_ATSC_16_VSB</constant>) were defined. Note the +<constant>V4L2_STD_525_60</constant> set now includes +<constant>V4L2_STD_NTSC_443</constant>. See also <xref + linkend="v4l2-std-id" />.</para> + </listitem> + + <listitem> + <para>The <constant>VIDIOC_G_COMP</constant> and +<constant>VIDIOC_S_COMP</constant> ioctl were renamed to +<constant>VIDIOC_G_MPEGCOMP</constant> and +<constant>VIDIOC_S_MPEGCOMP</constant> respectively. Their argument +was replaced by a struct +<structname>v4l2_mpeg_compression</structname> pointer. (The +<constant>VIDIOC_G_MPEGCOMP</constant> and +<constant>VIDIOC_S_MPEGCOMP</constant> ioctls where removed in Linux +2.6.25.)</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2005-11-27</title> + <para>The capture example in <xref linkend="capture-example" /> +called the &VIDIOC-S-CROP; ioctl without checking if cropping is +supported. In the video standard selection example in +<xref linkend="standard" /> the &VIDIOC-S-STD; call used the wrong +argument type.</para> + </section> + + <section> + <title>V4L2 spec erratum 2006-01-10</title> + <orderedlist> + <listitem> + <para>The <constant>V4L2_IN_ST_COLOR_KILL</constant> flag in +&v4l2-input; not only indicates if the color killer is enabled, but +also if it is active. (The color killer disables color decoding when +it detects no color in the video signal to improve the image +quality.)</para> + </listitem> + + <listitem> + <para>&VIDIOC-S-PARM; is a write-read ioctl, not write-only as +stated on its reference page. The ioctl changed in 2003 as noted above.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2006-02-03</title> + <orderedlist> + <listitem> + <para>In &v4l2-captureparm; and &v4l2-outputparm; the +<structfield>timeperframe</structfield> field gives the time in +seconds, not microseconds.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2006-02-04</title> + <orderedlist> + <listitem> + <para>The <structfield>clips</structfield> field in +&v4l2-window; must point to an array of &v4l2-clip;, not a linked +list, because drivers ignore the struct +<structname>v4l2_clip</structname>.<structfield>next</structfield> +pointer.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.17</title> + <orderedlist> + <listitem> + <para>New video standard macros were added: +<constant>V4L2_STD_NTSC_M_KR</constant> (NTSC M South Korea), and the +sets <constant>V4L2_STD_MN</constant>, +<constant>V4L2_STD_B</constant>, <constant>V4L2_STD_GH</constant> and +<constant>V4L2_STD_DK</constant>. The +<constant>V4L2_STD_NTSC</constant> and +<constant>V4L2_STD_SECAM</constant> sets now include +<constant>V4L2_STD_NTSC_M_KR</constant> and +<constant>V4L2_STD_SECAM_LC</constant> respectively.</para> + </listitem> + + <listitem> + <para>A new <constant>V4L2_TUNER_MODE_LANG1_LANG2</constant> +was defined to record both languages of a bilingual program. The +use of <constant>V4L2_TUNER_MODE_STEREO</constant> for this purpose +is deprecated now. See the &VIDIOC-G-TUNER; section for +details.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2006-09-23 (Draft 0.15)</title> + <orderedlist> + <listitem> + <para>In various places +<constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> and +<constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant> of the sliced VBI +interface were not mentioned along with other buffer types.</para> + </listitem> + + <listitem> + <para>In <xref linkend="vidioc-g-audio" /> it was clarified +that the &v4l2-audio; <structfield>mode</structfield> field is a flags +field.</para> + </listitem> + + <listitem> + <para><xref linkend="vidioc-querycap" /> did not mention the +sliced VBI and radio capability flags.</para> + </listitem> + + <listitem> + <para>In <xref linkend="vidioc-g-frequency" /> it was +clarified that applications must initialize the tuner +<structfield>type</structfield> field of &v4l2-frequency; before +calling &VIDIOC-S-FREQUENCY;.</para> + </listitem> + + <listitem> + <para>The <structfield>reserved</structfield> array +in &v4l2-requestbuffers; has 2 elements, not 32.</para> + </listitem> + + <listitem> + <para>In <xref linkend="output" /> and <xref + linkend="raw-vbi" /> the device file names +<filename>/dev/vout</filename> which never caught on were replaced +by <filename>/dev/video</filename>.</para> + </listitem> + + <listitem> + <para>With Linux 2.6.15 the possible range for VBI device minor +numbers was extended from 224-239 to 224-255. Accordingly device file names +<filename>/dev/vbi0</filename> to <filename>/dev/vbi31</filename> are +possible now.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.18</title> + <orderedlist> + <listitem> + <para>New ioctls &VIDIOC-G-EXT-CTRLS;, &VIDIOC-S-EXT-CTRLS; +and &VIDIOC-TRY-EXT-CTRLS; were added, a flag to skip unsupported +controls with &VIDIOC-QUERYCTRL;, new control types +<constant>V4L2_CTRL_TYPE_INTEGER64</constant> and +<constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant> (<xref + linkend="v4l2-ctrl-type" />), and new control flags +<constant>V4L2_CTRL_FLAG_READ_ONLY</constant>, +<constant>V4L2_CTRL_FLAG_UPDATE</constant>, +<constant>V4L2_CTRL_FLAG_INACTIVE</constant> and +<constant>V4L2_CTRL_FLAG_SLIDER</constant> (<xref + linkend="control-flags" />). See <xref + linkend="extended-controls" /> for details.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.19</title> + <orderedlist> + <listitem> + <para>In &v4l2-sliced-vbi-cap; a buffer type field was added +replacing a reserved field. Note on architectures where the size of +enum types differs from int types the size of the structure changed. +The &VIDIOC-G-SLICED-VBI-CAP; ioctl was redefined from being read-only +to write-read. Applications must initialize the type field and clear +the reserved fields now. These changes may <emphasis>break the +compatibility</emphasis> with older drivers and applications.</para> + </listitem> + + <listitem> + <para>The ioctls &VIDIOC-ENUM-FRAMESIZES; and +&VIDIOC-ENUM-FRAMEINTERVALS; were added.</para> + </listitem> + + <listitem> + <para>A new pixel format <constant>V4L2_PIX_FMT_RGB444</constant> (<xref +linkend="rgb-formats" />) was added.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 spec erratum 2006-10-12 (Draft 0.17)</title> + <orderedlist> + <listitem> + <para><constant>V4L2_PIX_FMT_HM12</constant> (<xref +linkend="reserved-formats" />) is a YUV 4:2:0, not 4:2:2 format.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.21</title> + <orderedlist> + <listitem> + <para>The <filename>videodev2.h</filename> header file is +now dual licensed under GNU General Public License version two or +later, and under a 3-clause BSD-style license.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.22</title> + <orderedlist> + <listitem> + <para>Two new field orders + <constant>V4L2_FIELD_INTERLACED_TB</constant> and + <constant>V4L2_FIELD_INTERLACED_BT</constant> were + added. See <xref linkend="v4l2-field" /> for details.</para> + </listitem> + + <listitem> + <para>Three new clipping/blending methods with a global or +straight or inverted local alpha value were added to the video overlay +interface. See the description of the &VIDIOC-G-FBUF; and +&VIDIOC-S-FBUF; ioctls for details.</para> + <para>A new <structfield>global_alpha</structfield> field +was added to <link +linkend="v4l2-window"><structname>v4l2_window</structname></link>, +extending the structure. This may <emphasis>break +compatibility</emphasis> with applications using a struct +<structname>v4l2_window</structname> directly. However the <link +linkend="vidioc-g-fmt">VIDIOC_G/S/TRY_FMT</link> ioctls, which take a +pointer to a <link linkend="v4l2-format">v4l2_format</link> parent +structure with padding bytes at the end, are not affected.</para> + </listitem> + + <listitem> + <para>The format of the <structfield>chromakey</structfield> +field in &v4l2-window; changed from "host order RGB32" to a pixel +value in the same format as the framebuffer. This may <emphasis>break +compatibility</emphasis> with existing applications. Drivers +supporting the "host order RGB32" format are not known.</para> + </listitem> + + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.24</title> + <orderedlist> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_PAL8</constant>, +<constant>V4L2_PIX_FMT_YUV444</constant>, +<constant>V4L2_PIX_FMT_YUV555</constant>, +<constant>V4L2_PIX_FMT_YUV565</constant> and +<constant>V4L2_PIX_FMT_YUV32</constant> were added.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.25</title> + <orderedlist> + <listitem> + <para>The pixel formats <link linkend="V4L2-PIX-FMT-Y16"> +<constant>V4L2_PIX_FMT_Y16</constant></link> and <link +linkend="V4L2-PIX-FMT-SBGGR16"> +<constant>V4L2_PIX_FMT_SBGGR16</constant></link> were added.</para> + </listitem> + <listitem> + <para>New <link linkend="control">controls</link> +<constant>V4L2_CID_POWER_LINE_FREQUENCY</constant>, +<constant>V4L2_CID_HUE_AUTO</constant>, +<constant>V4L2_CID_WHITE_BALANCE_TEMPERATURE</constant>, +<constant>V4L2_CID_SHARPNESS</constant> and +<constant>V4L2_CID_BACKLIGHT_COMPENSATION</constant> were added. The +controls <constant>V4L2_CID_BLACK_LEVEL</constant>, +<constant>V4L2_CID_WHITENESS</constant>, +<constant>V4L2_CID_HCENTER</constant> and +<constant>V4L2_CID_VCENTER</constant> were deprecated. +</para> + </listitem> + <listitem> + <para>A <link linkend="camera-controls">Camera controls +class</link> was added, with the new controls +<constant>V4L2_CID_EXPOSURE_AUTO</constant>, +<constant>V4L2_CID_EXPOSURE_ABSOLUTE</constant>, +<constant>V4L2_CID_EXPOSURE_AUTO_PRIORITY</constant>, +<constant>V4L2_CID_PAN_RELATIVE</constant>, +<constant>V4L2_CID_TILT_RELATIVE</constant>, +<constant>V4L2_CID_PAN_RESET</constant>, +<constant>V4L2_CID_TILT_RESET</constant>, +<constant>V4L2_CID_PAN_ABSOLUTE</constant>, +<constant>V4L2_CID_TILT_ABSOLUTE</constant>, +<constant>V4L2_CID_FOCUS_ABSOLUTE</constant>, +<constant>V4L2_CID_FOCUS_RELATIVE</constant> and +<constant>V4L2_CID_FOCUS_AUTO</constant>.</para> + </listitem> + <listitem> + <para>The <constant>VIDIOC_G_MPEGCOMP</constant> and +<constant>VIDIOC_S_MPEGCOMP</constant> ioctls, which were superseded +by the <link linkend="extended-controls">extended controls</link> +interface in Linux 2.6.18, where finally removed from the +<filename>videodev2.h</filename> header file.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.26</title> + <orderedlist> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_Y16</constant> and +<constant>V4L2_PIX_FMT_SBGGR16</constant> were added.</para> + </listitem> + <listitem> + <para>Added user controls +<constant>V4L2_CID_CHROMA_AGC</constant> and +<constant>V4L2_CID_COLOR_KILLER</constant>.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.27</title> + <orderedlist> + <listitem> + <para>The &VIDIOC-S-HW-FREQ-SEEK; ioctl and the +<constant>V4L2_CAP_HW_FREQ_SEEK</constant> capability were added.</para> + </listitem> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_YVYU</constant>, +<constant>V4L2_PIX_FMT_PCA501</constant>, +<constant>V4L2_PIX_FMT_PCA505</constant>, +<constant>V4L2_PIX_FMT_PCA508</constant>, +<constant>V4L2_PIX_FMT_PCA561</constant>, +<constant>V4L2_PIX_FMT_SGBRG8</constant>, +<constant>V4L2_PIX_FMT_PAC207</constant> and +<constant>V4L2_PIX_FMT_PJPG</constant> were added.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.28</title> + <orderedlist> + <listitem> + <para>Added <constant>V4L2_MPEG_AUDIO_ENCODING_AAC</constant> and +<constant>V4L2_MPEG_AUDIO_ENCODING_AC3</constant> MPEG audio encodings.</para> + </listitem> + <listitem> + <para>Added <constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC</constant> MPEG +video encoding.</para> + </listitem> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_SGRBG10</constant> and +<constant>V4L2_PIX_FMT_SGRBG10DPCM8</constant> were added.</para> + </listitem> + </orderedlist> + </section> + + <section> + <title>V4L2 in Linux 2.6.29</title> + <orderedlist> + <listitem> + <para>The <constant>VIDIOC_G_CHIP_IDENT</constant> ioctl was renamed +to <constant>VIDIOC_G_CHIP_IDENT_OLD</constant> and &VIDIOC-DBG-G-CHIP-IDENT; +was introduced in its place. The old struct <structname>v4l2_chip_ident</structname> +was renamed to <structname id="v4l2-chip-ident-old">v4l2_chip_ident_old</structname>.</para> + </listitem> + <listitem> + <para>The pixel formats +<constant>V4L2_PIX_FMT_VYUY</constant>, +<constant>V4L2_PIX_FMT_NV16</constant> and +<constant>V4L2_PIX_FMT_NV61</constant> were added.</para> + </listitem> + <listitem> + <para>Added camera controls +<constant>V4L2_CID_ZOOM_ABSOLUTE</constant>, +<constant>V4L2_CID_ZOOM_RELATIVE</constant>, +<constant>V4L2_CID_ZOOM_CONTINUOUS</constant> and +<constant>V4L2_CID_PRIVACY</constant>.</para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 2.6.30</title> + <orderedlist> + <listitem> + <para>New control flag <constant>V4L2_CTRL_FLAG_WRITE_ONLY</constant> was added.</para> + </listitem> + <listitem> + <para>New control <constant>V4L2_CID_COLORFX</constant> was added.</para> + </listitem> + </orderedlist> + </section> + <section> + <title>V4L2 in Linux 2.6.32</title> + <orderedlist> + <listitem> + <para>In order to be easier to compare a V4L2 API and a kernel +version, now V4L2 API is numbered using the Linux Kernel version numeration.</para> + </listitem> + <listitem> + <para>Finalized the RDS capture API. See <xref linkend="rds" /> for +more information.</para> + </listitem> + <listitem> + <para>Added new capabilities for modulators and RDS encoders.</para> + </listitem> + <listitem> + <para>Add description for libv4l API.</para> + </listitem> + <listitem> + <para>Added support for string controls via new type <constant>V4L2_CTRL_TYPE_STRING</constant>.</para> + </listitem> + <listitem> + <para>Added <constant>V4L2_CID_BAND_STOP_FILTER</constant> documentation.</para> + </listitem> + <listitem> + <para>Added FM Modulator (FM TX) Extended Control Class: <constant>V4L2_CTRL_CLASS_FM_TX</constant> and their Control IDs.</para> + </listitem> + <listitem> + <para>Added Remote Controller chapter, describing the default Remote Controller mapping for media devices.</para> + </listitem> + </orderedlist> + </section> + </section> + + <section id="other"> + <title>Relation of V4L2 to other Linux multimedia APIs</title> + + <section id="xvideo"> + <title>X Video Extension</title> + + <para>The X Video Extension (abbreviated XVideo or just Xv) is +an extension of the X Window system, implemented for example by the +XFree86 project. Its scope is similar to V4L2, an API to video capture +and output devices for X clients. Xv allows applications to display +live video in a window, send window contents to a TV output, and +capture or output still images in XPixmaps<footnote> + <para>This is not implemented in XFree86.</para> + </footnote>. With their implementation XFree86 makes the +extension available across many operating systems and +architectures.</para> + + <para>Because the driver is embedded into the X server Xv has a +number of advantages over the V4L2 <link linkend="overlay">video +overlay interface</link>. The driver can easily determine the overlay +target, &ie; visible graphics memory or off-screen buffers for a +destructive overlay. It can program the RAMDAC for a non-destructive +overlay, scaling or color-keying, or the clipping functions of the +video capture hardware, always in sync with drawing operations or +windows moving or changing their stacking order.</para> + + <para>To combine the advantages of Xv and V4L a special Xv +driver exists in XFree86 and XOrg, just programming any overlay capable +Video4Linux device it finds. To enable it +<filename>/etc/X11/XF86Config</filename> must contain these lines:</para> + <para><screen> +Section "Module" + Load "v4l" +EndSection</screen></para> + + <para>As of XFree86 4.2 this driver still supports only V4L +ioctls, however it should work just fine with all V4L2 devices through +the V4L2 backward-compatibility layer. Since V4L2 permits multiple +opens it is possible (if supported by the V4L2 driver) to capture +video while an X client requested video overlay. Restrictions of +simultaneous capturing and overlay are discussed in <xref + linkend="overlay" /> apply.</para> + + <para>Only marginally related to V4L2, XFree86 extended Xv to +support hardware YUV to RGB conversion and scaling for faster video +playback, and added an interface to MPEG-2 decoding hardware. This API +is useful to display images captured with V4L2 devices.</para> + </section> + + <section> + <title>Digital Video</title> + + <para>V4L2 does not support digital terrestrial, cable or +satellite broadcast. A separate project aiming at digital receivers +exists. You can find its homepage at <ulink +url="http://linuxtv.org">http://linuxtv.org</ulink>. The Linux DVB API +has no connection to the V4L2 API except that drivers for hybrid +hardware may support both.</para> + </section> + + <section> + <title>Audio Interfaces</title> + + <para>[to do - OSS/ALSA]</para> + </section> + </section> + + <section id="experimental"> + <title>Experimental API Elements</title> + + <para>The following V4L2 API elements are currently experimental +and may change in the future.</para> + + <itemizedlist> + <listitem> + <para>Video Output Overlay (OSD) Interface, <xref + linkend="osd" />.</para> + </listitem> + <listitem> + <para><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY</constant>, + &v4l2-buf-type;, <xref linkend="v4l2-buf-type" />.</para> + </listitem> + <listitem> + <para><constant>V4L2_CAP_VIDEO_OUTPUT_OVERLAY</constant>, +&VIDIOC-QUERYCAP; ioctl, <xref linkend="device-capabilities" />.</para> + </listitem> + <listitem> + <para>&VIDIOC-ENUM-FRAMESIZES; and +&VIDIOC-ENUM-FRAMEINTERVALS; ioctls.</para> + </listitem> + <listitem> + <para>&VIDIOC-G-ENC-INDEX; ioctl.</para> + </listitem> + <listitem> + <para>&VIDIOC-ENCODER-CMD; and &VIDIOC-TRY-ENCODER-CMD; +ioctls.</para> + </listitem> + <listitem> + <para>&VIDIOC-DBG-G-REGISTER; and &VIDIOC-DBG-S-REGISTER; +ioctls.</para> + </listitem> + <listitem> + <para>&VIDIOC-DBG-G-CHIP-IDENT; ioctl.</para> + </listitem> + </itemizedlist> + </section> + + <section id="obsolete"> + <title>Obsolete API Elements</title> + + <para>The following V4L2 API elements were superseded by new +interfaces and should not be implemented in new drivers.</para> + + <itemizedlist> + <listitem> + <para><constant>VIDIOC_G_MPEGCOMP</constant> and +<constant>VIDIOC_S_MPEGCOMP</constant> ioctls. Use Extended Controls, +<xref linkend="extended-controls" />.</para> + </listitem> + </itemizedlist> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/controls.xml b/Documentation/DocBook/v4l/controls.xml new file mode 100644 index 0000000..f492acc --- /dev/null +++ b/Documentation/DocBook/v4l/controls.xml @@ -0,0 +1,2049 @@ + <section id="control"> + <title>User Controls</title> + + <para>Devices typically have a number of user-settable controls +such as brightness, saturation and so on, which would be presented to +the user on a graphical user interface. But, different devices +will have different controls available, and furthermore, the range of +possible values, and the default value will vary from device to +device. The control ioctls provide the information and a mechanism to +create a nice user interface for these controls that will work +correctly with any device.</para> + + <para>All controls are accessed using an ID value. V4L2 defines +several IDs for specific purposes. Drivers can also implement their +own custom controls using <constant>V4L2_CID_PRIVATE_BASE</constant> +and higher values. The pre-defined control IDs have the prefix +<constant>V4L2_CID_</constant>, and are listed in <xref +linkend="control-id" />. The ID is used when querying the attributes of +a control, and when getting or setting the current value.</para> + + <para>Generally applications should present controls to the user +without assumptions about their purpose. Each control comes with a +name string the user is supposed to understand. When the purpose is +non-intuitive the driver writer should provide a user manual, a user +interface plug-in or a driver specific panel application. Predefined +IDs were introduced to change a few controls programmatically, for +example to mute a device during a channel switch.</para> + + <para>Drivers may enumerate different controls after switching +the current video input or output, tuner or modulator, or audio input +or output. Different in the sense of other bounds, another default and +current value, step size or other menu items. A control with a certain +<emphasis>custom</emphasis> ID can also change name and +type.<footnote> + <para>It will be more convenient for applications if drivers +make use of the <constant>V4L2_CTRL_FLAG_DISABLED</constant> flag, but +that was never required.</para> + </footnote> Control values are stored globally, they do not +change when switching except to stay within the reported bounds. They +also do not change ⪚ when the device is opened or closed, when the +tuner radio frequency is changed or generally never without +application request. Since V4L2 specifies no event mechanism, panel +applications intended to cooperate with other panel applications (be +they built into a larger application, as a TV viewer) may need to +regularly poll control values to update their user +interface.<footnote> + <para>Applications could call an ioctl to request events. +After another process called &VIDIOC-S-CTRL; or another ioctl changing +shared properties the &func-select; function would indicate +readability until any ioctl (querying the properties) is +called.</para> + </footnote></para> + + <table pgwide="1" frame="none" id="control-id"> + <title>Control IDs</title> + <tgroup cols="3"> + &cs-def; + <thead> + <row> + <entry>ID</entry> + <entry>Type</entry> + <entry>Description</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_CID_BASE</constant></entry> + <entry></entry> + <entry>First predefined ID, equal to +<constant>V4L2_CID_BRIGHTNESS</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_CID_USER_BASE</constant></entry> + <entry></entry> + <entry>Synonym of <constant>V4L2_CID_BASE</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_CID_BRIGHTNESS</constant></entry> + <entry>integer</entry> + <entry>Picture brightness, or more precisely, the black +level.</entry> + </row> + <row> + <entry><constant>V4L2_CID_CONTRAST</constant></entry> + <entry>integer</entry> + <entry>Picture contrast or luma gain.</entry> + </row> + <row> + <entry><constant>V4L2_CID_SATURATION</constant></entry> + <entry>integer</entry> + <entry>Picture color saturation or chroma gain.</entry> + </row> + <row> + <entry><constant>V4L2_CID_HUE</constant></entry> + <entry>integer</entry> + <entry>Hue or color balance.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_VOLUME</constant></entry> + <entry>integer</entry> + <entry>Overall audio volume. Note some drivers also +provide an OSS or ALSA mixer interface.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_BALANCE</constant></entry> + <entry>integer</entry> + <entry>Audio stereo balance. Minimum corresponds to all +the way left, maximum to right.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_BASS</constant></entry> + <entry>integer</entry> + <entry>Audio bass adjustment.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_TREBLE</constant></entry> + <entry>integer</entry> + <entry>Audio treble adjustment.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_MUTE</constant></entry> + <entry>boolean</entry> + <entry>Mute audio, &ie; set the volume to zero, however +without affecting <constant>V4L2_CID_AUDIO_VOLUME</constant>. Like +ALSA drivers, V4L2 drivers must mute at load time to avoid excessive +noise. Actually the entire device should be reset to a low power +consumption state.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUDIO_LOUDNESS</constant></entry> + <entry>boolean</entry> + <entry>Loudness mode (bass boost).</entry> + </row> + <row> + <entry><constant>V4L2_CID_BLACK_LEVEL</constant></entry> + <entry>integer</entry> + <entry>Another name for brightness (not a synonym of +<constant>V4L2_CID_BRIGHTNESS</constant>). This control is deprecated +and should not be used in new drivers and applications.</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUTO_WHITE_BALANCE</constant></entry> + <entry>boolean</entry> + <entry>Automatic white balance (cameras).</entry> + </row> + <row> + <entry><constant>V4L2_CID_DO_WHITE_BALANCE</constant></entry> + <entry>button</entry> + <entry>This is an action control. When set (the value is +ignored), the device will do a white balance and then hold the current +setting. Contrast this with the boolean +<constant>V4L2_CID_AUTO_WHITE_BALANCE</constant>, which, when +activated, keeps adjusting the white balance.</entry> + </row> + <row> + <entry><constant>V4L2_CID_RED_BALANCE</constant></entry> + <entry>integer</entry> + <entry>Red chroma balance.</entry> + </row> + <row> + <entry><constant>V4L2_CID_BLUE_BALANCE</constant></entry> + <entry>integer</entry> + <entry>Blue chroma balance.</entry> + </row> + <row> + <entry><constant>V4L2_CID_GAMMA</constant></entry> + <entry>integer</entry> + <entry>Gamma adjust.</entry> + </row> + <row> + <entry><constant>V4L2_CID_WHITENESS</constant></entry> + <entry>integer</entry> + <entry>Whiteness for grey-scale devices. This is a synonym +for <constant>V4L2_CID_GAMMA</constant>. This control is deprecated +and should not be used in new drivers and applications.</entry> + </row> + <row> + <entry><constant>V4L2_CID_EXPOSURE</constant></entry> + <entry>integer</entry> + <entry>Exposure (cameras). [Unit?]</entry> + </row> + <row> + <entry><constant>V4L2_CID_AUTOGAIN</constant></entry> + <entry>boolean</entry> + <entry>Automatic gain/exposure control.</entry> + </row> + <row> + <entry><constant>V4L2_CID_GAIN</constant></entry> + <entry>integer</entry> + <entry>Gain control.</entry> + </row> + <row> + <entry><constant>V4L2_CID_HFLIP</constant></entry> + <entry>boolean</entry> + <entry>Mirror the picture horizontally.</entry> + </row> + <row> + <entry><constant>V4L2_CID_VFLIP</constant></entry> + <entry>boolean</entry> + <entry>Mirror the picture vertically.</entry> + </row> + <row> + <entry><constant>V4L2_CID_HCENTER_DEPRECATED</constant> (formerly <constant>V4L2_CID_HCENTER</constant>)</entry> + <entry>integer</entry> + <entry>Horizontal image centering. This control is +deprecated. New drivers and applications should use the <link +linkend="camera-controls">Camera class controls</link> +<constant>V4L2_CID_PAN_ABSOLUTE</constant>, +<constant>V4L2_CID_PAN_RELATIVE</constant> and +<constant>V4L2_CID_PAN_RESET</constant> instead.</entry> + </row> + <row> + <entry><constant>V4L2_CID_VCENTER_DEPRECATED</constant> + (formerly <constant>V4L2_CID_VCENTER</constant>)</entry> + <entry>integer</entry> + <entry>Vertical image centering. Centering is intended to +<emphasis>physically</emphasis> adjust cameras. For image cropping see +<xref linkend="crop" />, for clipping <xref linkend="overlay" />. This +control is deprecated. New drivers and applications should use the +<link linkend="camera-controls">Camera class controls</link> +<constant>V4L2_CID_TILT_ABSOLUTE</constant>, +<constant>V4L2_CID_TILT_RELATIVE</constant> and +<constant>V4L2_CID_TILT_RESET</constant> instead.</entry> + </row> + <row id="v4l2-power-line-frequency"> + <entry><constant>V4L2_CID_POWER_LINE_FREQUENCY</constant></entry> + <entry>enum</entry> + <entry>Enables a power line frequency filter to avoid +flicker. Possible values for <constant>enum v4l2_power_line_frequency</constant> are: +<constant>V4L2_CID_POWER_LINE_FREQUENCY_DISABLED</constant> (0), +<constant>V4L2_CID_POWER_LINE_FREQUENCY_50HZ</constant> (1) and +<constant>V4L2_CID_POWER_LINE_FREQUENCY_60HZ</constant> (2).</entry> + </row> + <row> + <entry><constant>V4L2_CID_HUE_AUTO</constant></entry> + <entry>boolean</entry> + <entry>Enables automatic hue control by the device. The +effect of setting <constant>V4L2_CID_HUE</constant> while automatic +hue control is enabled is undefined, drivers should ignore such +request.</entry> + </row> + <row> + <entry><constant>V4L2_CID_WHITE_BALANCE_TEMPERATURE</constant></entry> + <entry>integer</entry> + <entry>This control specifies the white balance settings +as a color temperature in Kelvin. A driver should have a minimum of +2800 (incandescent) to 6500 (daylight). For more information about +color temperature see <ulink +url="http://en.wikipedia.org/wiki/Color_temperature">Wikipedia</ulink>.</entry> + </row> + <row> + <entry><constant>V4L2_CID_SHARPNESS</constant></entry> + <entry>integer</entry> + <entry>Adjusts the sharpness filters in a camera. The +minimum value disables the filters, higher values give a sharper +picture.</entry> + </row> + <row> + <entry><constant>V4L2_CID_BACKLIGHT_COMPENSATION</constant></entry> + <entry>integer</entry> + <entry>Adjusts the backlight compensation in a camera. The +minimum value disables backlight compensation.</entry> + </row> + <row> + <entry><constant>V4L2_CID_CHROMA_AGC</constant></entry> + <entry>boolean</entry> + <entry>Chroma automatic gain control.</entry> + </row> + <row> + <entry><constant>V4L2_CID_COLOR_KILLER</constant></entry> + <entry>boolean</entry> + <entry>Enable the color killer (&ie; force a black & white image in case of a weak video signal).</entry> + </row> + <row id="v4l2-colorfx"> + <entry><constant>V4L2_CID_COLORFX</constant></entry> + <entry>enum</entry> + <entry>Selects a color effect. Possible values for +<constant>enum v4l2_colorfx</constant> are: +<constant>V4L2_COLORFX_NONE</constant> (0), +<constant>V4L2_COLORFX_BW</constant> (1) and +<constant>V4L2_COLORFX_SEPIA</constant> (2).</entry> + </row> + <row> + <entry><constant>V4L2_CID_LASTP1</constant></entry> + <entry></entry> + <entry>End of the predefined control IDs (currently +<constant>V4L2_CID_COLORFX</constant> + 1).</entry> + </row> + <row> + <entry><constant>V4L2_CID_PRIVATE_BASE</constant></entry> + <entry></entry> + <entry>ID of the first custom (driver specific) control. +Applications depending on particular custom controls should check the +driver name and version, see <xref linkend="querycap" />.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Applications can enumerate the available controls with the +&VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls, get and set a +control value with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls. +Drivers must implement <constant>VIDIOC_QUERYCTRL</constant>, +<constant>VIDIOC_G_CTRL</constant> and +<constant>VIDIOC_S_CTRL</constant> when the device has one or more +controls, <constant>VIDIOC_QUERYMENU</constant> when it has one or +more menu type controls.</para> + + <example> + <title>Enumerating all controls</title> + + <programlisting> +&v4l2-queryctrl; queryctrl; +&v4l2-querymenu; querymenu; + +static void +enumerate_menu (void) +{ + printf (" Menu items:\n"); + + memset (&querymenu, 0, sizeof (querymenu)); + querymenu.id = queryctrl.id; + + for (querymenu.index = queryctrl.minimum; + querymenu.index <= queryctrl.maximum; + querymenu.index++) { + if (0 == ioctl (fd, &VIDIOC-QUERYMENU;, &querymenu)) { + printf (" %s\n", querymenu.name); + } else { + perror ("VIDIOC_QUERYMENU"); + exit (EXIT_FAILURE); + } + } +} + +memset (&queryctrl, 0, sizeof (queryctrl)); + +for (queryctrl.id = V4L2_CID_BASE; + queryctrl.id < V4L2_CID_LASTP1; + queryctrl.id++) { + if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) + continue; + + printf ("Control %s\n", queryctrl.name); + + if (queryctrl.type == V4L2_CTRL_TYPE_MENU) + enumerate_menu (); + } else { + if (errno == EINVAL) + continue; + + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } +} + +for (queryctrl.id = V4L2_CID_PRIVATE_BASE;; + queryctrl.id++) { + if (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) + continue; + + printf ("Control %s\n", queryctrl.name); + + if (queryctrl.type == V4L2_CTRL_TYPE_MENU) + enumerate_menu (); + } else { + if (errno == EINVAL) + break; + + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } +} +</programlisting> + </example> + + <example> + <title>Changing controls</title> + + <programlisting> +&v4l2-queryctrl; queryctrl; +&v4l2-control; control; + +memset (&queryctrl, 0, sizeof (queryctrl)); +queryctrl.id = V4L2_CID_BRIGHTNESS; + +if (-1 == ioctl (fd, &VIDIOC-QUERYCTRL;, &queryctrl)) { + if (errno != EINVAL) { + perror ("VIDIOC_QUERYCTRL"); + exit (EXIT_FAILURE); + } else { + printf ("V4L2_CID_BRIGHTNESS is not supported\n"); + } +} else if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) { + printf ("V4L2_CID_BRIGHTNESS is not supported\n"); +} else { + memset (&control, 0, sizeof (control)); + control.id = V4L2_CID_BRIGHTNESS; + control.value = queryctrl.default_value; + + if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &control)) { + perror ("VIDIOC_S_CTRL"); + exit (EXIT_FAILURE); + } +} + +memset (&control, 0, sizeof (control)); +control.id = V4L2_CID_CONTRAST; + +if (0 == ioctl (fd, &VIDIOC-G-CTRL;, &control)) { + control.value += 1; + + /* The driver may clamp the value or return ERANGE, ignored here */ + + if (-1 == ioctl (fd, &VIDIOC-S-CTRL;, &control) + && errno != ERANGE) { + perror ("VIDIOC_S_CTRL"); + exit (EXIT_FAILURE); + } +/* Ignore if V4L2_CID_CONTRAST is unsupported */ +} else if (errno != EINVAL) { + perror ("VIDIOC_G_CTRL"); + exit (EXIT_FAILURE); +} + +control.id = V4L2_CID_AUDIO_MUTE; +control.value = TRUE; /* silence */ + +/* Errors ignored */ +ioctl (fd, VIDIOC_S_CTRL, &control); +</programlisting> + </example> + </section> + + <section id="extended-controls"> + <title>Extended Controls</title> + + <section> + <title>Introduction</title> + + <para>The control mechanism as originally designed was meant +to be used for user settings (brightness, saturation, etc). However, +it turned out to be a very useful model for implementing more +complicated driver APIs where each driver implements only a subset of +a larger API.</para> + + <para>The MPEG encoding API was the driving force behind +designing and implementing this extended control mechanism: the MPEG +standard is quite large and the currently supported hardware MPEG +encoders each only implement a subset of this standard. Further more, +many parameters relating to how the video is encoded into an MPEG +stream are specific to the MPEG encoding chip since the MPEG standard +only defines the format of the resulting MPEG stream, not how the +video is actually encoded into that format.</para> + + <para>Unfortunately, the original control API lacked some +features needed for these new uses and so it was extended into the +(not terribly originally named) extended control API.</para> + + <para>Even though the MPEG encoding API was the first effort +to use the Extended Control API, nowadays there are also other classes +of Extended Controls, such as Camera Controls and FM Transmitter Controls. +The Extended Controls API as well as all Extended Controls classes are +described in the following text.</para> + </section> + + <section> + <title>The Extended Control API</title> + + <para>Three new ioctls are available: &VIDIOC-G-EXT-CTRLS;, +&VIDIOC-S-EXT-CTRLS; and &VIDIOC-TRY-EXT-CTRLS;. These ioctls act on +arrays of controls (as opposed to the &VIDIOC-G-CTRL; and +&VIDIOC-S-CTRL; ioctls that act on a single control). This is needed +since it is often required to atomically change several controls at +once.</para> + + <para>Each of the new ioctls expects a pointer to a +&v4l2-ext-controls;. This structure contains a pointer to the control +array, a count of the number of controls in that array and a control +class. Control classes are used to group similar controls into a +single class. For example, control class +<constant>V4L2_CTRL_CLASS_USER</constant> contains all user controls +(&ie; all controls that can also be set using the old +<constant>VIDIOC_S_CTRL</constant> ioctl). Control class +<constant>V4L2_CTRL_CLASS_MPEG</constant> contains all controls +relating to MPEG encoding, etc.</para> + + <para>All controls in the control array must belong to the +specified control class. An error is returned if this is not the +case.</para> + + <para>It is also possible to use an empty control array (count +== 0) to check whether the specified control class is +supported.</para> + + <para>The control array is a &v4l2-ext-control; array. The +<structname>v4l2_ext_control</structname> structure is very similar to +&v4l2-control;, except for the fact that it also allows for 64-bit +values and pointers to be passed.</para> + + <para>It is important to realize that due to the flexibility of +controls it is necessary to check whether the control you want to set +actually is supported in the driver and what the valid range of values +is. So use the &VIDIOC-QUERYCTRL; and &VIDIOC-QUERYMENU; ioctls to +check this. Also note that it is possible that some of the menu +indices in a control of type <constant>V4L2_CTRL_TYPE_MENU</constant> +may not be supported (<constant>VIDIOC_QUERYMENU</constant> will +return an error). A good example is the list of supported MPEG audio +bitrates. Some drivers only support one or two bitrates, others +support a wider range.</para> + </section> + + <section> + <title>Enumerating Extended Controls</title> + + <para>The recommended way to enumerate over the extended +controls is by using &VIDIOC-QUERYCTRL; in combination with the +<constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> flag:</para> + + <informalexample> + <programlisting> +&v4l2-queryctrl; qctrl; + +qctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL; +while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &qctrl)) { + /* ... */ + qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL; +} +</programlisting> + </informalexample> + + <para>The initial control ID is set to 0 ORed with the +<constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> flag. The +<constant>VIDIOC_QUERYCTRL</constant> ioctl will return the first +control with a higher ID than the specified one. When no such controls +are found an error is returned.</para> + + <para>If you want to get all controls within a specific control +class, then you can set the initial +<structfield>qctrl.id</structfield> value to the control class and add +an extra check to break out of the loop when a control of another +control class is found:</para> + + <informalexample> + <programlisting> +qctrl.id = V4L2_CTRL_CLASS_MPEG | V4L2_CTRL_FLAG_NEXT_CTRL; +while (0 == ioctl (fd, &VIDIOC-QUERYCTRL;, &qctrl)) { + if (V4L2_CTRL_ID2CLASS (qctrl.id) != V4L2_CTRL_CLASS_MPEG) + break; + /* ... */ + qctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL; + } +</programlisting> + </informalexample> + + <para>The 32-bit <structfield>qctrl.id</structfield> value is +subdivided into three bit ranges: the top 4 bits are reserved for +flags (⪚ <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant>) and are not +actually part of the ID. The remaining 28 bits form the control ID, of +which the most significant 12 bits define the control class and the +least significant 16 bits identify the control within the control +class. It is guaranteed that these last 16 bits are always non-zero +for controls. The range of 0x1000 and up are reserved for +driver-specific controls. The macro +<constant>V4L2_CTRL_ID2CLASS(id)</constant> returns the control class +ID based on a control ID.</para> + + <para>If the driver does not support extended controls, then +<constant>VIDIOC_QUERYCTRL</constant> will fail when used in +combination with <constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant>. In +that case the old method of enumerating control should be used (see +1.8). But if it is supported, then it is guaranteed to enumerate over +all controls, including driver-private controls.</para> + </section> + + <section> + <title>Creating Control Panels</title> + + <para>It is possible to create control panels for a graphical +user interface where the user can select the various controls. +Basically you will have to iterate over all controls using the method +described above. Each control class starts with a control of type +<constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant>. +<constant>VIDIOC_QUERYCTRL</constant> will return the name of this +control class which can be used as the title of a tab page within a +control panel.</para> + + <para>The flags field of &v4l2-queryctrl; also contains hints on +the behavior of the control. See the &VIDIOC-QUERYCTRL; documentation +for more details.</para> + </section> + + <section id="mpeg-controls"> + <title>MPEG Control Reference</title> + + <para>Below all controls within the MPEG control class are +described. First the generic controls, then controls specific for +certain hardware.</para> + + <section> + <title>Generic MPEG Controls</title> + + <table pgwide="1" frame="none" id="mpeg-control-id"> + <title>MPEG Control IDs</title> + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CLASS</constant> </entry> + <entry>class</entry> + </row><row><entry spanname="descr">The MPEG class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class. This description can be used as the +caption of a Tab page in a GUI, for example.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-stream-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_stream_type</entry> + </row><row><entry spanname="descr">The MPEG-1, -2 or -4 +output stream type. One cannot assume anything here. Each hardware +MPEG encoder tends to support different subsets of the available MPEG +stream types. The currently defined stream types are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_PS</constant> </entry> + <entry>MPEG-2 program stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_TS</constant> </entry> + <entry>MPEG-2 transport stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG1_SS</constant> </entry> + <entry>MPEG-1 system stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_DVD</constant> </entry> + <entry>MPEG-2 DVD-compatible stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG1_VCD</constant> </entry> + <entry>MPEG-1 VCD-compatible stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_TYPE_MPEG2_SVCD</constant> </entry> + <entry>MPEG-2 SVCD-compatible stream</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_PMT</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Program Map Table +Packet ID for the MPEG transport stream (default 16)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_AUDIO</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Audio Packet ID for +the MPEG transport stream (default 256)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_VIDEO</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Video Packet ID for +the MPEG transport stream (default 260)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PID_PCR</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Packet ID for the +MPEG transport stream carrying PCR fields (default 259)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PES_ID_AUDIO</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Audio ID for MPEG +PES</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_PES_ID_VIDEO</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Video ID for MPEG +PES</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-stream-vbi-fmt"> + <entry spanname="id"><constant>V4L2_CID_MPEG_STREAM_VBI_FMT</constant> </entry> + <entry>enum v4l2_mpeg_stream_vbi_fmt</entry> + </row><row><entry spanname="descr">Some cards can embed +VBI data (⪚ Closed Caption, Teletext) into the MPEG stream. This +control selects whether VBI data should be embedded, and if so, what +embedding method should be used. The list of possible VBI formats +depends on the driver. The currently defined VBI format types +are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_NONE</constant> </entry> + <entry>No VBI in the MPEG stream</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_STREAM_VBI_FMT_IVTV</constant> </entry> + <entry>VBI in private packets, IVTV format (documented +in the kernel sources in the file <filename>Documentation/video4linux/cx2341x/README.vbi</filename>)</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-sampling-freq"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ</constant> </entry> + <entry>enum v4l2_mpeg_audio_sampling_freq</entry> + </row><row><entry spanname="descr">MPEG Audio sampling +frequency. Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_44100</constant> </entry> + <entry>44.1 kHz</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_48000</constant> </entry> + <entry>48 kHz</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_SAMPLING_FREQ_32000</constant> </entry> + <entry>32 kHz</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-encoding"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_ENCODING</constant> </entry> + <entry>enum v4l2_mpeg_audio_encoding</entry> + </row><row><entry spanname="descr">MPEG Audio encoding. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_1</constant> </entry> + <entry>MPEG-1/2 Layer I encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_2</constant> </entry> + <entry>MPEG-1/2 Layer II encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_LAYER_3</constant> </entry> + <entry>MPEG-1/2 Layer III encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_AAC</constant> </entry> + <entry>MPEG-2/4 AAC (Advanced Audio Coding)</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_ENCODING_AC3</constant> </entry> + <entry>AC-3 aka ATSC A/52 encoding</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-l1-bitrate"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L1_BITRATE</constant> </entry> + <entry>enum v4l2_mpeg_audio_l1_bitrate</entry> + </row><row><entry spanname="descr">MPEG-1/2 Layer I bitrate. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_32K</constant> </entry> + <entry>32 kbit/s</entry></row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_64K</constant> </entry> + <entry>64 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_96K</constant> </entry> + <entry>96 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_128K</constant> </entry> + <entry>128 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_160K</constant> </entry> + <entry>160 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_192K</constant> </entry> + <entry>192 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_224K</constant> </entry> + <entry>224 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_256K</constant> </entry> + <entry>256 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_288K</constant> </entry> + <entry>288 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_320K</constant> </entry> + <entry>320 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_352K</constant> </entry> + <entry>352 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_384K</constant> </entry> + <entry>384 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_416K</constant> </entry> + <entry>416 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L1_BITRATE_448K</constant> </entry> + <entry>448 kbit/s</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-l2-bitrate"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L2_BITRATE</constant> </entry> + <entry>enum v4l2_mpeg_audio_l2_bitrate</entry> + </row><row><entry spanname="descr">MPEG-1/2 Layer II bitrate. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_32K</constant> </entry> + <entry>32 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_48K</constant> </entry> + <entry>48 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_56K</constant> </entry> + <entry>56 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_64K</constant> </entry> + <entry>64 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_80K</constant> </entry> + <entry>80 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_96K</constant> </entry> + <entry>96 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_112K</constant> </entry> + <entry>112 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_128K</constant> </entry> + <entry>128 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_160K</constant> </entry> + <entry>160 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_192K</constant> </entry> + <entry>192 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_224K</constant> </entry> + <entry>224 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_256K</constant> </entry> + <entry>256 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_320K</constant> </entry> + <entry>320 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L2_BITRATE_384K</constant> </entry> + <entry>384 kbit/s</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-l3-bitrate"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_L3_BITRATE</constant> </entry> + <entry>enum v4l2_mpeg_audio_l3_bitrate</entry> + </row><row><entry spanname="descr">MPEG-1/2 Layer III bitrate. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_32K</constant> </entry> + <entry>32 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_40K</constant> </entry> + <entry>40 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_48K</constant> </entry> + <entry>48 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_56K</constant> </entry> + <entry>56 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_64K</constant> </entry> + <entry>64 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_80K</constant> </entry> + <entry>80 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_96K</constant> </entry> + <entry>96 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_112K</constant> </entry> + <entry>112 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_128K</constant> </entry> + <entry>128 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_160K</constant> </entry> + <entry>160 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_192K</constant> </entry> + <entry>192 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_224K</constant> </entry> + <entry>224 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_256K</constant> </entry> + <entry>256 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_L3_BITRATE_320K</constant> </entry> + <entry>320 kbit/s</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_AAC_BITRATE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">AAC bitrate in bits per second.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-ac3-bitrate"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_AC3_BITRATE</constant> </entry> + <entry>enum v4l2_mpeg_audio_ac3_bitrate</entry> + </row><row><entry spanname="descr">AC-3 bitrate. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_32K</constant> </entry> + <entry>32 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_40K</constant> </entry> + <entry>40 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_48K</constant> </entry> + <entry>48 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_56K</constant> </entry> + <entry>56 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_64K</constant> </entry> + <entry>64 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_80K</constant> </entry> + <entry>80 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_96K</constant> </entry> + <entry>96 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_112K</constant> </entry> + <entry>112 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_128K</constant> </entry> + <entry>128 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_160K</constant> </entry> + <entry>160 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_192K</constant> </entry> + <entry>192 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_224K</constant> </entry> + <entry>224 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_256K</constant> </entry> + <entry>256 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_320K</constant> </entry> + <entry>320 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_384K</constant> </entry> + <entry>384 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_448K</constant> </entry> + <entry>448 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_512K</constant> </entry> + <entry>512 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_576K</constant> </entry> + <entry>576 kbit/s</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_AC3_BITRATE_640K</constant> </entry> + <entry>640 kbit/s</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MODE</constant> </entry> + <entry>enum v4l2_mpeg_audio_mode</entry> + </row><row><entry spanname="descr">MPEG Audio mode. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_STEREO</constant> </entry> + <entry>Stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_JOINT_STEREO</constant> </entry> + <entry>Joint Stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_DUAL</constant> </entry> + <entry>Bilingual</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_MONO</constant> </entry> + <entry>Mono</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-mode-extension"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MODE_EXTENSION</constant> </entry> + <entry>enum v4l2_mpeg_audio_mode_extension</entry> + </row><row><entry spanname="descr">Joint Stereo +audio mode extension. In Layer I and II they indicate which subbands +are in intensity stereo. All other subbands are coded in stereo. Layer +III is not (yet) supported. Possible values +are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_4</constant> </entry> + <entry>Subbands 4-31 in intensity stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_8</constant> </entry> + <entry>Subbands 8-31 in intensity stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_12</constant> </entry> + <entry>Subbands 12-31 in intensity stereo</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_16</constant> </entry> + <entry>Subbands 16-31 in intensity stereo</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-emphasis"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_EMPHASIS</constant> </entry> + <entry>enum v4l2_mpeg_audio_emphasis</entry> + </row><row><entry spanname="descr">Audio Emphasis. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_NONE</constant> </entry> + <entry>None</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_50_DIV_15_uS</constant> </entry> + <entry>50/15 microsecond emphasis</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_EMPHASIS_CCITT_J17</constant> </entry> + <entry>CCITT J.17</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-audio-crc"> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_CRC</constant> </entry> + <entry>enum v4l2_mpeg_audio_crc</entry> + </row><row><entry spanname="descr">CRC method. Possible +values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_AUDIO_CRC_NONE</constant> </entry> + <entry>None</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_AUDIO_CRC_CRC16</constant> </entry> + <entry>16 bit parity check</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_AUDIO_MUTE</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Mutes the audio when +capturing. This is not done by muting audio hardware, which can still +produce a slight hiss, but in the encoder itself, guaranteeing a fixed +and reproducable audio bitstream. 0 = unmuted, 1 = muted.</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-video-encoding"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_ENCODING</constant> </entry> + <entry>enum v4l2_mpeg_video_encoding</entry> + </row><row><entry spanname="descr">MPEG Video encoding +method. Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_1</constant> </entry> + <entry>MPEG-1 Video encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_2</constant> </entry> + <entry>MPEG-2 Video encoding</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC</constant> </entry> + <entry>MPEG-4 AVC (H.264) Video encoding</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-video-aspect"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_ASPECT</constant> </entry> + <entry>enum v4l2_mpeg_video_aspect</entry> + </row><row><entry spanname="descr">Video aspect. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ASPECT_1x1</constant> </entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ASPECT_4x3</constant> </entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ASPECT_16x9</constant> </entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_ASPECT_221x100</constant> </entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_B_FRAMES</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Number of B-Frames +(default 2)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_GOP_SIZE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">GOP size (default +12)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_GOP_CLOSURE</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">GOP closure (default +1)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_PULLDOWN</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Enable 3:2 pulldown +(default 0)</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-video-bitrate-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE_MODE</constant> </entry> + <entry>enum v4l2_mpeg_video_bitrate_mode</entry> + </row><row><entry spanname="descr">Video bitrate mode. +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VIDEO_BITRATE_MODE_VBR</constant> </entry> + <entry>Variable bitrate</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VIDEO_BITRATE_MODE_CBR</constant> </entry> + <entry>Constant bitrate</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Video bitrate in bits +per second.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_BITRATE_PEAK</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Peak video bitrate in +bits per second. Must be larger or equal to the average video bitrate. +It is ignored if the video bitrate mode is set to constant +bitrate.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">For every captured +frame, skip this many subsequent frames (default 0).</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MUTE</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">"Mutes" the video to a +fixed color when capturing. This is useful for testing, to produce a +fixed video bitstream. 0 = unmuted, 1 = muted.</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MUTE_YUV</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Sets the "mute" color +of the video. The supplied 32-bit integer is interpreted as follows (bit +0 = least significant bit):</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry>Bit 0:7</entry> + <entry>V chrominance information</entry> + </row> + <row> + <entry>Bit 8:15</entry> + <entry>U chrominance information</entry> + </row> + <row> + <entry>Bit 16:23</entry> + <entry>Y luminance information</entry> + </row> + <row> + <entry>Bit 24:31</entry> + <entry>Must be zero.</entry> + </row> + </tbody> + </entrytbl> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section> + <title>CX2341x MPEG Controls</title> + + <para>The following MPEG class controls deal with MPEG +encoding settings that are specific to the Conexant CX23415 and +CX23416 MPEG encoding chips.</para> + + <table pgwide="1" frame="none" id="cx2341x-control-id"> + <title>CX2341x Control IDs</title> + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row id="v4l2-mpeg-cx2341x-video-spatial-filter-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_spatial_filter_mode</entry> + </row><row><entry spanname="descr">Sets the Spatial +Filter mode (default <constant>MANUAL</constant>). Possible values +are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_MANUAL</constant> </entry> + <entry>Choose the filter manually</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_AUTO</constant> </entry> + <entry>Choose the filter automatically</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER</constant> </entry> + <entry>integer (0-15)</entry> + </row><row><entry spanname="descr">The setting for the +Spatial Filter. 0 = off, 15 = maximum. (Default is 0.)</entry> + </row> + <row><entry></entry></row> + <row id="luma-spatial-filter-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_luma_spatial_filter_type</entry> + </row><row><entry spanname="descr">Select the algorithm +to use for the Luma Spatial Filter (default +<constant>1D_HOR</constant>). Possible values:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_OFF</constant> </entry> + <entry>No filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_HOR</constant> </entry> + <entry>One-dimensional horizontal</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_VERT</constant> </entry> + <entry>One-dimensional vertical</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_HV_SEPARABLE</constant> </entry> + <entry>Two-dimensional separable</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_SYM_NON_SEPARABLE</constant> </entry> + <entry>Two-dimensional symmetrical +non-separable</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="chroma-spatial-filter-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_chroma_spatial_filter_type</entry> + </row><row><entry spanname="descr">Select the algorithm +for the Chroma Spatial Filter (default <constant>1D_HOR</constant>). +Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_OFF</constant> </entry> + <entry>No filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_1D_HOR</constant> </entry> + <entry>One-dimensional horizontal</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-cx2341x-video-temporal-filter-mode"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_temporal_filter_mode</entry> + </row><row><entry spanname="descr">Sets the Temporal +Filter mode (default <constant>MANUAL</constant>). Possible values +are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_MANUAL</constant> </entry> + <entry>Choose the filter manually</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_AUTO</constant> </entry> + <entry>Choose the filter automatically</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER</constant> </entry> + <entry>integer (0-31)</entry> + </row><row><entry spanname="descr">The setting for the +Temporal Filter. 0 = off, 31 = maximum. (Default is 8 for full-scale +capturing and 0 for scaled capturing.)</entry> + </row> + <row><entry></entry></row> + <row id="v4l2-mpeg-cx2341x-video-median-filter-type"> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE</constant> </entry> + <entry>enum v4l2_mpeg_cx2341x_video_median_filter_type</entry> + </row><row><entry spanname="descr">Median Filter Type +(default <constant>OFF</constant>). Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_OFF</constant> </entry> + <entry>No filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR</constant> </entry> + <entry>Horizontal filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_VERT</constant> </entry> + <entry>Vertical filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR_VERT</constant> </entry> + <entry>Horizontal and vertical filter</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_DIAG</constant> </entry> + <entry>Diagonal filter</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_BOTTOM</constant> </entry> + <entry>integer (0-255)</entry> + </row><row><entry spanname="descr">Threshold above which +the luminance median filter is enabled (default 0)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_TOP</constant> </entry> + <entry>integer (0-255)</entry> + </row><row><entry spanname="descr">Threshold below which +the luminance median filter is enabled (default 255)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_BOTTOM</constant> </entry> + <entry>integer (0-255)</entry> + </row><row><entry spanname="descr">Threshold above which +the chroma median filter is enabled (default 0)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_TOP</constant> </entry> + <entry>integer (0-255)</entry> + </row><row><entry spanname="descr">Threshold below which +the chroma median filter is enabled (default 255)</entry> + </row> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_MPEG_CX2341X_STREAM_INSERT_NAV_PACKETS</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">The CX2341X MPEG encoder +can insert one empty MPEG-2 PES packet into the stream between every +four video frames. The packet size is 2048 bytes, including the +packet_start_code_prefix and stream_id fields. The stream_id is 0xBF +(private stream 2). The payload consists of 0x00 bytes, to be filled +in by the application. 0 = do not insert, 1 = insert packets.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + </section> + + <section id="camera-controls"> + <title>Camera Control Reference</title> + + <para>The Camera class includes controls for mechanical (or +equivalent digital) features of a device such as controllable lenses +or sensors.</para> + + <table pgwide="1" frame="none" id="camera-control-id"> + <title>Camera Control IDs</title> + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_CAMERA_CLASS</constant> </entry> + <entry>class</entry> + </row><row><entry spanname="descr">The Camera class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class.</entry> + </row> + <row><entry></entry></row> + + <row id="v4l2-exposure-auto-type"> + <entry spanname="id"><constant>V4L2_CID_EXPOSURE_AUTO</constant> </entry> + <entry>enum v4l2_exposure_auto_type</entry> + </row><row><entry spanname="descr">Enables automatic +adjustments of the exposure time and/or iris aperture. The effect of +manual changes of the exposure time or iris aperture while these +features are enabled is undefined, drivers should ignore such +requests. Possible values are:</entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_EXPOSURE_AUTO</constant> </entry> + <entry>Automatic exposure time, automatic iris +aperture.</entry> + </row> + <row> + <entry><constant>V4L2_EXPOSURE_MANUAL</constant> </entry> + <entry>Manual exposure time, manual iris.</entry> + </row> + <row> + <entry><constant>V4L2_EXPOSURE_SHUTTER_PRIORITY</constant> </entry> + <entry>Manual exposure time, auto iris.</entry> + </row> + <row> + <entry><constant>V4L2_EXPOSURE_APERTURE_PRIORITY</constant> </entry> + <entry>Auto exposure time, manual iris.</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_EXPOSURE_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Determines the exposure +time of the camera sensor. The exposure time is limited by the frame +interval. Drivers should interpret the values as 100 µs units, +where the value 1 stands for 1/10000th of a second, 10000 for 1 second +and 100000 for 10 seconds.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_EXPOSURE_AUTO_PRIORITY</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">When +<constant>V4L2_CID_EXPOSURE_AUTO</constant> is set to +<constant>AUTO</constant> or <constant>APERTURE_PRIORITY</constant>, +this control determines if the device may dynamically vary the frame +rate. By default this feature is disabled (0) and the frame rate must +remain constant.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_PAN_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control turns the +camera horizontally by the specified amount. The unit is undefined. A +positive value moves the camera to the right (clockwise when viewed +from above), a negative value to the left. A value of zero does not +cause motion. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_TILT_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control turns the +camera vertically by the specified amount. The unit is undefined. A +positive value moves the camera up, a negative value down. A value of +zero does not cause motion. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_PAN_RESET</constant> </entry> + <entry>button</entry> + </row><row><entry spanname="descr">When this control is set, +the camera moves horizontally to the default position.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_TILT_RESET</constant> </entry> + <entry>button</entry> + </row><row><entry spanname="descr">When this control is set, +the camera moves vertically to the default position.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_PAN_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control +turns the camera horizontally to the specified position. Positive +values move the camera to the right (clockwise when viewed from above), +negative values to the left. Drivers should interpret the values as arc +seconds, with valid values between -180 * 3600 and +180 * 3600 +inclusive.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_TILT_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control +turns the camera vertically to the specified position. Positive values +move the camera up, negative values down. Drivers should interpret the +values as arc seconds, with valid values between -180 * 3600 and +180 +* 3600 inclusive.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_FOCUS_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control sets the +focal point of the camera to the specified position. The unit is +undefined. Positive values set the focus closer to the camera, +negative values towards infinity.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_FOCUS_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">This control moves the +focal point of the camera by the specified amount. The unit is +undefined. Positive values move the focus closer to the camera, +negative values towards infinity. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_FOCUS_AUTO</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Enables automatic focus +adjustments. The effect of manual focus adjustments while this feature +is enabled is undefined, drivers should ignore such requests.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_ZOOM_ABSOLUTE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Specify the objective lens +focal length as an absolute value. The zoom unit is driver-specific and its +value should be a positive integer.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_ZOOM_RELATIVE</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Specify the objective lens +focal length relatively to the current value. Positive values move the zoom +lens group towards the telephoto direction, negative values towards the +wide-angle direction. The zoom unit is driver-specific. This is a write-only control.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_ZOOM_CONTINUOUS</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Move the objective lens group +at the specified speed until it reaches physical device limits or until an +explicit request to stop the movement. A positive value moves the zoom lens +group towards the telephoto direction. A value of zero stops the zoom lens +group movement. A negative value moves the zoom lens group towards the +wide-angle direction. The zoom speed unit is driver-specific.</entry> + </row> + <row><entry></entry></row> + + <row> + <entry spanname="id"><constant>V4L2_CID_PRIVACY</constant> </entry> + <entry>boolean</entry> + </row><row><entry spanname="descr">Prevent video from being acquired +by the camera. When this control is set to <constant>TRUE</constant> (1), no +image can be captured by the camera. Common means to enforce privacy are +mechanical obturation of the sensor and firmware image processing, but the +device is not restricted to these methods. Devices that implement the privacy +control must support read access and may support write access.</entry> + </row> + + <row> + <entry spanname="id"><constant>V4L2_CID_BAND_STOP_FILTER</constant> </entry> + <entry>integer</entry> + </row><row><entry spanname="descr">Switch the band-stop filter of a +camera sensor on or off, or specify its strength. Such band-stop filters can +be used, for example, to filter out the fluorescent light component.</entry> + </row> + <row><entry></entry></row> + </tbody> + </tgroup> + </table> + </section> + + <section id="fm-tx-controls"> + <title>FM Transmitter Control Reference</title> + + <para>The FM Transmitter (FM_TX) class includes controls for common features of +FM transmissions capable devices. Currently this class includes parameters for audio +compression, pilot tone generation, audio deviation limiter, RDS transmission and +tuning power features.</para> + + <table pgwide="1" frame="none" id="fm-tx-control-id"> + <title>FM_TX Control IDs</title> + + <tgroup cols="4"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="6*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="6*" /> + <spanspec namest="c1" nameend="c2" spanname="id" /> + <spanspec namest="c2" nameend="c4" spanname="descr" /> + <thead> + <row> + <entry spanname="id" align="left">ID</entry> + <entry align="left">Type</entry> + </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_FM_TX_CLASS</constant> </entry> + <entry>class</entry> + </row><row><entry spanname="descr">The FM_TX class +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a +description of this control class.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_DEVIATION</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Configures RDS signal frequency deviation level in Hz. +The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_PI</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the RDS Programme Identification field +for transmission.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_PTY</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the RDS Programme Type field for transmission. +This encodes up to 31 pre-defined programme types.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_PS_NAME</constant> </entry> + <entry>string</entry> + </row> + <row><entry spanname="descr">Sets the Programme Service name (PS_NAME) for transmission. +It is intended for static display on a receiver. It is the primary aid to listeners in programme service +identification and selection. In Annex E of <xref linkend="en50067" />, the RDS specification, +there is a full description of the correct character encoding for Programme Service name strings. +Also from RDS specification, PS is usually a single eight character text. However, it is also possible +to find receivers which can scroll strings sized as 8 x N characters. So, this control must be configured +with steps of 8 characters. The result is it must always contain a string with size multiple of 8.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_RDS_TX_RADIO_TEXT</constant> </entry> + <entry>string</entry> + </row> + <row><entry spanname="descr">Sets the Radio Text info for transmission. It is a textual description of +what is being broadcasted. RDS Radio Text can be applied when broadcaster wishes to transmit longer PS names, +programme-related information or any other text. In these cases, RadioText should be used in addition to +<constant>V4L2_CID_RDS_TX_PS_NAME</constant>. The encoding for Radio Text strings is also fully described +in Annex E of <xref linkend="en50067" />. The length of Radio Text strings depends on which RDS Block is being +used to transmit it, either 32 (2A block) or 64 (2B block). However, it is also possible +to find receivers which can scroll strings sized as 32 x N or 64 x N characters. So, this control must be configured +with steps of 32 or 64 characters. The result is it must always contain a string with size multiple of 32 or 64. </entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_ENABLED</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enables or disables the audio deviation limiter feature. +The limiter is useful when trying to maximize the audio volume, minimize receiver-generated +distortion and prevent overmodulation. +</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_RELEASE_TIME</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the audio deviation limiter feature release time. +Unit is in useconds. Step and range are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_DEVIATION</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Configures audio frequency deviation level in Hz. +The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ENABLED</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enables or disables the audio compression feature. +This feature amplifies signals below the threshold by a fixed gain and compresses audio +signals above the threshold by the ratio of Threshold/(Gain + Threshold).</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_GAIN</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the gain for audio compression feature. It is +a dB value. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_THRESHOLD</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the threshold level for audio compression freature. +It is a dB value. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the attack time for audio compression feature. +It is a useconds value. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the release time for audio compression feature. +It is a useconds value. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_ENABLED</constant> </entry> + <entry>boolean</entry> + </row> + <row><entry spanname="descr">Enables or disables the pilot tone generation feature.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_DEVIATION</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Configures pilot tone frequency deviation level. Unit is +in Hz. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_FREQUENCY</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Configures pilot tone frequency value. Unit is +in Hz. The range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_TUNE_PREEMPHASIS</constant> </entry> + <entry>integer</entry> + </row> + <row id="v4l2-preemphasis"><entry spanname="descr">Configures the pre-emphasis value for broadcasting. +A pre-emphasis filter is applied to the broadcast to accentuate the high audio frequencies. +Depending on the region, a time constant of either 50 or 75 useconds is used. The enum v4l2_preemphasis +defines possible values for pre-emphasis. Here they are:</entry> + </row><row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_PREEMPHASIS_DISABLED</constant> </entry> + <entry>No pre-emphasis is applied.</entry> + </row> + <row> + <entry><constant>V4L2_PREEMPHASIS_50_uS</constant> </entry> + <entry>A pre-emphasis of 50 uS is used.</entry> + </row> + <row> + <entry><constant>V4L2_PREEMPHASIS_75_uS</constant> </entry> + <entry>A pre-emphasis of 75 uS is used.</entry> + </row> + </tbody> + </entrytbl> + + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_TUNE_POWER_LEVEL</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">Sets the output power level for signal transmission. +Unit is in dBuV. Range and step are driver-specific.</entry> + </row> + <row> + <entry spanname="id"><constant>V4L2_CID_TUNE_ANTENNA_CAPACITOR</constant> </entry> + <entry>integer</entry> + </row> + <row><entry spanname="descr">This selects the value of antenna tuning capacitor +manually or automatically if set to zero. Unit, range and step are driver-specific.</entry> + </row> + <row><entry></entry></row> + </tbody> + </tgroup> + </table> + +<para>For more details about RDS specification, refer to +<xref linkend="en50067" /> document, from CENELEC.</para> + </section> +</section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "common.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/crop.gif b/Documentation/DocBook/v4l/crop.gif Binary files differnew file mode 100644 index 0000000..3b9e7d8 --- /dev/null +++ b/Documentation/DocBook/v4l/crop.gif diff --git a/Documentation/DocBook/v4l/crop.pdf b/Documentation/DocBook/v4l/crop.pdf Binary files differnew file mode 100644 index 0000000..c9fb81c --- /dev/null +++ b/Documentation/DocBook/v4l/crop.pdf diff --git a/Documentation/DocBook/v4l/dev-capture.xml b/Documentation/DocBook/v4l/dev-capture.xml new file mode 100644 index 0000000..32807e4 --- /dev/null +++ b/Documentation/DocBook/v4l/dev-capture.xml @@ -0,0 +1,115 @@ + <title>Video Capture Interface</title> + + <para>Video capture devices sample an analog video signal and store +the digitized images in memory. Today nearly all devices can capture +at full 25 or 30 frames/second. With this interface applications can +control the capture process and move images from the driver into user +space.</para> + + <para>Conventionally V4L2 video capture devices are accessed through +character device special files named <filename>/dev/video</filename> +and <filename>/dev/video0</filename> to +<filename>/dev/video63</filename> with major number 81 and minor +numbers 0 to 63. <filename>/dev/video</filename> is typically a +symbolic link to the preferred video device. Note the same device +files are used for video output devices.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the video capture interface set the +<constant>V4L2_CAP_VIDEO_CAPTURE</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. As secondary device functions +they may also support the <link linkend="overlay">video overlay</link> +(<constant>V4L2_CAP_VIDEO_OVERLAY</constant>) and the <link +linkend="raw-vbi">raw VBI capture</link> +(<constant>V4L2_CAP_VBI_CAPTURE</constant>) interface. At least one of +the read/write or streaming I/O methods must be supported. Tuners and +audio inputs are optional.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Video capture devices shall support <link +linkend="audio">audio input</link>, <link +linkend="tuner">tuner</link>, <link linkend="control">controls</link>, +<link linkend="crop">cropping and scaling</link> and <link +linkend="streaming-par">streaming parameter</link> ioctls as needed. +The <link linkend="video">video input</link> and <link +linkend="standard">video standard</link> ioctls must be supported by +all video capture devices.</para> + </section> + + <section> + <title>Image Format Negotiation</title> + + <para>The result of a capture operation is determined by +cropping and image format parameters. The former select an area of the +video picture to capture, the latter how images are stored in memory, +&ie; in RGB or YUV format, the number of bits per pixel or width and +height. Together they also define how images are scaled in the +process.</para> + + <para>As usual these parameters are <emphasis>not</emphasis> reset +at &func-open; time to permit Unix tool chains, programming a device +and then reading from it as if it was a plain file. Well written V4L2 +applications ensure they really get what they want, including cropping +and scaling.</para> + + <para>Cropping initialization at minimum requires to reset the +parameters to defaults. An example is given in <xref +linkend="crop" />.</para> + + <para>To query the current image format applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-pix-format; <structfield>pix</structfield> member of the +<structfield>fmt</structfield> union.</para> + + <para>To request different parameters applications set the +<structfield>type</structfield> field of a &v4l2-format; as above and +initialize all fields of the &v4l2-pix-format; +<structfield>vbi</structfield> member of the +<structfield>fmt</structfield> union, or better just modify the +results of <constant>VIDIOC_G_FMT</constant>, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers may +adjust the parameters and finally return the actual parameters as +<constant>VIDIOC_G_FMT</constant> does.</para> + + <para>Like <constant>VIDIOC_S_FMT</constant> the +&VIDIOC-TRY-FMT; ioctl can be used to learn about hardware limitations +without disabling I/O or possibly time consuming hardware +preparations.</para> + + <para>The contents of &v4l2-pix-format; are discussed in <xref +linkend="pixfmt" />. See also the specification of the +<constant>VIDIOC_G_FMT</constant>, <constant>VIDIOC_S_FMT</constant> +and <constant>VIDIOC_TRY_FMT</constant> ioctls for details. Video +capture devices must implement both the +<constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl, even if +<constant>VIDIOC_S_FMT</constant> ignores all requests and always +returns default parameters as <constant>VIDIOC_G_FMT</constant> does. +<constant>VIDIOC_TRY_FMT</constant> is optional.</para> + </section> + + <section> + <title>Reading Images</title> + + <para>A video capture device may support the <link +linkend="rw">read() function</link> and/or streaming (<link +linkend="mmap">memory mapping</link> or <link +linkend="userp">user pointer</link>) I/O. See <xref +linkend="io" /> for details.</para> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-codec.xml b/Documentation/DocBook/v4l/dev-codec.xml new file mode 100644 index 0000000..6e156dc --- /dev/null +++ b/Documentation/DocBook/v4l/dev-codec.xml @@ -0,0 +1,26 @@ + <title>Codec Interface</title> + + <note> + <title>Suspended</title> + + <para>This interface has been be suspended from the V4L2 API +implemented in Linux 2.6 until we have more experience with codec +device interfaces.</para> + </note> + + <para>A V4L2 codec can compress, decompress, transform, or otherwise +convert video data from one format into another format, in memory. +Applications send data to be converted to the driver through a +&func-write; call, and receive the converted data through a +&func-read; call. For efficiency a driver may also support streaming +I/O.</para> + + <para>[to do]</para> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-effect.xml b/Documentation/DocBook/v4l/dev-effect.xml new file mode 100644 index 0000000..9c243be --- /dev/null +++ b/Documentation/DocBook/v4l/dev-effect.xml @@ -0,0 +1,25 @@ + <title>Effect Devices Interface</title> + + <note> + <title>Suspended</title> + + <para>This interface has been be suspended from the V4L2 API +implemented in Linux 2.6 until we have more experience with effect +device interfaces.</para> + </note> + + <para>A V4L2 video effect device can do image effects, filtering, or +combine two or more images or image streams. For example video +transitions or wipes. Applications send data to be processed and +receive the result data either with &func-read; and &func-write; +functions, or through the streaming I/O mechanism.</para> + + <para>[to do]</para> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-osd.xml b/Documentation/DocBook/v4l/dev-osd.xml new file mode 100644 index 0000000..c9a68a2 --- /dev/null +++ b/Documentation/DocBook/v4l/dev-osd.xml @@ -0,0 +1,164 @@ + <title>Video Output Overlay Interface</title> + <subtitle>Also known as On-Screen Display (OSD)</subtitle> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>Some video output devices can overlay a framebuffer image onto +the outgoing video signal. Applications can set up such an overlay +using this interface, which borrows structures and ioctls of the <link +linkend="overlay">Video Overlay</link> interface.</para> + + <para>The OSD function is accessible through the same character +special file as the <link linkend="capture">Video Output</link> function. +Note the default function of such a <filename>/dev/video</filename> device +is video capturing or output. The OSD function is only available after +calling the &VIDIOC-S-FMT; ioctl.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the <wordasword>Video Output +Overlay</wordasword> interface set the +<constant>V4L2_CAP_VIDEO_OUTPUT_OVERLAY</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl.</para> + </section> + + <section> + <title>Framebuffer</title> + + <para>Contrary to the <wordasword>Video Overlay</wordasword> +interface the framebuffer is normally implemented on the TV card and +not the graphics card. On Linux it is accessible as a framebuffer +device (<filename>/dev/fbN</filename>). Given a V4L2 device, +applications can find the corresponding framebuffer device by calling +the &VIDIOC-G-FBUF; ioctl. It returns, amongst other information, the +physical address of the framebuffer in the +<structfield>base</structfield> field of &v4l2-framebuffer;. The +framebuffer device ioctl <constant>FBIOGET_FSCREENINFO</constant> +returns the same address in the <structfield>smem_start</structfield> +field of struct <structname>fb_fix_screeninfo</structname>. The +<constant>FBIOGET_FSCREENINFO</constant> ioctl and struct +<structname>fb_fix_screeninfo</structname> are defined in the +<filename>linux/fb.h</filename> header file.</para> + + <para>The width and height of the framebuffer depends on the +current video standard. A V4L2 driver may reject attempts to change +the video standard (or any other ioctl which would imply a framebuffer +size change) with an &EBUSY; until all applications closed the +framebuffer device.</para> + + <example> + <title>Finding a framebuffer device for OSD</title> + + <programlisting> +#include <linux/fb.h> + +&v4l2-framebuffer; fbuf; +unsigned int i; +int fb_fd; + +if (-1 == ioctl (fd, VIDIOC_G_FBUF, &fbuf)) { + perror ("VIDIOC_G_FBUF"); + exit (EXIT_FAILURE); +} + +for (i = 0; i > 30; ++i) { + char dev_name[16]; + struct fb_fix_screeninfo si; + + snprintf (dev_name, sizeof (dev_name), "/dev/fb%u", i); + + fb_fd = open (dev_name, O_RDWR); + if (-1 == fb_fd) { + switch (errno) { + case ENOENT: /* no such file */ + case ENXIO: /* no driver */ + continue; + + default: + perror ("open"); + exit (EXIT_FAILURE); + } + } + + if (0 == ioctl (fb_fd, FBIOGET_FSCREENINFO, &si)) { + if (si.smem_start == (unsigned long) fbuf.base) + break; + } else { + /* Apparently not a framebuffer device. */ + } + + close (fb_fd); + fb_fd = -1; +} + +/* fb_fd is the file descriptor of the framebuffer device + for the video output overlay, or -1 if no device was found. */ +</programlisting> + </example> + </section> + + <section> + <title>Overlay Window and Scaling</title> + + <para>The overlay is controlled by source and target rectangles. +The source rectangle selects a subsection of the framebuffer image to +be overlaid, the target rectangle an area in the outgoing video signal +where the image will appear. Drivers may or may not support scaling, +and arbitrary sizes and positions of these rectangles. Further drivers +may support any (or none) of the clipping/blending methods defined for +the <link linkend="overlay">Video Overlay</link> interface.</para> + + <para>A &v4l2-window; defines the size of the source rectangle, +its position in the framebuffer and the clipping/blending method to be +used for the overlay. To get the current parameters applications set +the <structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY</constant> and call the +&VIDIOC-G-FMT; ioctl. The driver fills the +<structname>v4l2_window</structname> substructure named +<structfield>win</structfield>. It is not possible to retrieve a +previously programmed clipping list or bitmap.</para> + + <para>To program the source rectangle applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY</constant>, initialize +the <structfield>win</structfield> substructure and call the +&VIDIOC-S-FMT; ioctl. The driver adjusts the parameters against +hardware limits and returns the actual parameters as +<constant>VIDIOC_G_FMT</constant> does. Like +<constant>VIDIOC_S_FMT</constant>, the &VIDIOC-TRY-FMT; ioctl can be +used to learn about driver capabilities without actually changing +driver state. Unlike <constant>VIDIOC_S_FMT</constant> this also works +after the overlay has been enabled.</para> + + <para>A &v4l2-crop; defines the size and position of the target +rectangle. The scaling factor of the overlay is implied by the width +and height given in &v4l2-window; and &v4l2-crop;. The cropping API +applies to <wordasword>Video Output</wordasword> and <wordasword>Video +Output Overlay</wordasword> devices in the same way as to +<wordasword>Video Capture</wordasword> and <wordasword>Video +Overlay</wordasword> devices, merely reversing the direction of the +data flow. For more information see <xref linkend="crop" />.</para> + </section> + + <section> + <title>Enabling Overlay</title> + + <para>There is no V4L2 ioctl to enable or disable the overlay, +however the framebuffer interface of the driver may support the +<constant>FBIOBLANK</constant> ioctl.</para> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-output.xml b/Documentation/DocBook/v4l/dev-output.xml new file mode 100644 index 0000000..63c3c20 --- /dev/null +++ b/Documentation/DocBook/v4l/dev-output.xml @@ -0,0 +1,111 @@ + <title>Video Output Interface</title> + + <para>Video output devices encode stills or image sequences as +analog video signal. With this interface applications can +control the encoding process and move images from user space to +the driver.</para> + + <para>Conventionally V4L2 video output devices are accessed through +character device special files named <filename>/dev/video</filename> +and <filename>/dev/video0</filename> to +<filename>/dev/video63</filename> with major number 81 and minor +numbers 0 to 63. <filename>/dev/video</filename> is typically a +symbolic link to the preferred video device. Note the same device +files are used for video capture devices.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the video output interface set the +<constant>V4L2_CAP_VIDEO_OUTPUT</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. As secondary device functions +they may also support the <link linkend="raw-vbi">raw VBI +output</link> (<constant>V4L2_CAP_VBI_OUTPUT</constant>) interface. At +least one of the read/write or streaming I/O methods must be +supported. Modulators and audio outputs are optional.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Video output devices shall support <link +linkend="audio">audio output</link>, <link +linkend="tuner">modulator</link>, <link linkend="control">controls</link>, +<link linkend="crop">cropping and scaling</link> and <link +linkend="streaming-par">streaming parameter</link> ioctls as needed. +The <link linkend="video">video output</link> and <link +linkend="standard">video standard</link> ioctls must be supported by +all video output devices.</para> + </section> + + <section> + <title>Image Format Negotiation</title> + + <para>The output is determined by cropping and image format +parameters. The former select an area of the video picture where the +image will appear, the latter how images are stored in memory, &ie; in +RGB or YUV format, the number of bits per pixel or width and height. +Together they also define how images are scaled in the process.</para> + + <para>As usual these parameters are <emphasis>not</emphasis> reset +at &func-open; time to permit Unix tool chains, programming a device +and then writing to it as if it was a plain file. Well written V4L2 +applications ensure they really get what they want, including cropping +and scaling.</para> + + <para>Cropping initialization at minimum requires to reset the +parameters to defaults. An example is given in <xref +linkend="crop" />.</para> + + <para>To query the current image format applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-pix-format; <structfield>pix</structfield> member of the +<structfield>fmt</structfield> union.</para> + + <para>To request different parameters applications set the +<structfield>type</structfield> field of a &v4l2-format; as above and +initialize all fields of the &v4l2-pix-format; +<structfield>vbi</structfield> member of the +<structfield>fmt</structfield> union, or better just modify the +results of <constant>VIDIOC_G_FMT</constant>, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers may +adjust the parameters and finally return the actual parameters as +<constant>VIDIOC_G_FMT</constant> does.</para> + + <para>Like <constant>VIDIOC_S_FMT</constant> the +&VIDIOC-TRY-FMT; ioctl can be used to learn about hardware limitations +without disabling I/O or possibly time consuming hardware +preparations.</para> + + <para>The contents of &v4l2-pix-format; are discussed in <xref +linkend="pixfmt" />. See also the specification of the +<constant>VIDIOC_G_FMT</constant>, <constant>VIDIOC_S_FMT</constant> +and <constant>VIDIOC_TRY_FMT</constant> ioctls for details. Video +output devices must implement both the +<constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl, even if +<constant>VIDIOC_S_FMT</constant> ignores all requests and always +returns default parameters as <constant>VIDIOC_G_FMT</constant> does. +<constant>VIDIOC_TRY_FMT</constant> is optional.</para> + </section> + + <section> + <title>Writing Images</title> + + <para>A video output device may support the <link +linkend="rw">write() function</link> and/or streaming (<link +linkend="mmap">memory mapping</link> or <link +linkend="userp">user pointer</link>) I/O. See <xref +linkend="io" /> for details.</para> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-overlay.xml b/Documentation/DocBook/v4l/dev-overlay.xml new file mode 100644 index 0000000..92513cf --- /dev/null +++ b/Documentation/DocBook/v4l/dev-overlay.xml @@ -0,0 +1,379 @@ + <title>Video Overlay Interface</title> + <subtitle>Also known as Framebuffer Overlay or Previewing</subtitle> + + <para>Video overlay devices have the ability to genlock (TV-)video +into the (VGA-)video signal of a graphics card, or to store captured +images directly in video memory of a graphics card, typically with +clipping. This can be considerable more efficient than capturing +images and displaying them by other means. In the old days when only +nuclear power plants needed cooling towers this used to be the only +way to put live video into a window.</para> + + <para>Video overlay devices are accessed through the same character +special files as <link linkend="capture">video capture</link> devices. +Note the default function of a <filename>/dev/video</filename> device +is video capturing. The overlay function is only available after +calling the &VIDIOC-S-FMT; ioctl.</para> + + <para>The driver may support simultaneous overlay and capturing +using the read/write and streaming I/O methods. If so, operation at +the nominal frame rate of the video standard is not guaranteed. Frames +may be directed away from overlay to capture, or one field may be used +for overlay and the other for capture if the capture parameters permit +this.</para> + + <para>Applications should use different file descriptors for +capturing and overlay. This must be supported by all drivers capable +of simultaneous capturing and overlay. Optionally these drivers may +also permit capturing and overlay with a single file descriptor for +compatibility with V4L and earlier versions of V4L2.<footnote> + <para>A common application of two file descriptors is the +XFree86 <link linkend="xvideo">Xv/V4L</link> interface driver and +a V4L2 application. While the X server controls video overlay, the +application can take advantage of memory mapping and DMA.</para> + <para>In the opinion of the designers of this API, no driver +writer taking the efforts to support simultaneous capturing and +overlay will restrict this ability by requiring a single file +descriptor, as in V4L and earlier versions of V4L2. Making this +optional means applications depending on two file descriptors need +backup routines to be compatible with all drivers, which is +considerable more work than using two fds in applications which do +not. Also two fd's fit the general concept of one file descriptor for +each logical stream. Hence as a complexity trade-off drivers +<emphasis>must</emphasis> support two file descriptors and +<emphasis>may</emphasis> support single fd operation.</para> + </footnote></para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the video overlay interface set the +<constant>V4L2_CAP_VIDEO_OVERLAY</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. The overlay I/O method specified +below must be supported. Tuners and audio inputs are optional.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Video overlay devices shall support <link +linkend="audio">audio input</link>, <link +linkend="tuner">tuner</link>, <link linkend="control">controls</link>, +<link linkend="crop">cropping and scaling</link> and <link +linkend="streaming-par">streaming parameter</link> ioctls as needed. +The <link linkend="video">video input</link> and <link +linkend="standard">video standard</link> ioctls must be supported by +all video overlay devices.</para> + </section> + + <section> + <title>Setup</title> + + <para>Before overlay can commence applications must program the +driver with frame buffer parameters, namely the address and size of +the frame buffer and the image format, for example RGB 5:6:5. The +&VIDIOC-G-FBUF; and &VIDIOC-S-FBUF; ioctls are available to get +and set these parameters, respectively. The +<constant>VIDIOC_S_FBUF</constant> ioctl is privileged because it +allows to set up DMA into physical memory, bypassing the memory +protection mechanisms of the kernel. Only the superuser can change the +frame buffer address and size. Users are not supposed to run TV +applications as root or with SUID bit set. A small helper application +with suitable privileges should query the graphics system and program +the V4L2 driver at the appropriate time.</para> + + <para>Some devices add the video overlay to the output signal +of the graphics card. In this case the frame buffer is not modified by +the video device, and the frame buffer address and pixel format are +not needed by the driver. The <constant>VIDIOC_S_FBUF</constant> ioctl +is not privileged. An application can check for this type of device by +calling the <constant>VIDIOC_G_FBUF</constant> ioctl.</para> + + <para>A driver may support any (or none) of five clipping/blending +methods:<orderedlist> + <listitem> + <para>Chroma-keying displays the overlaid image only where +pixels in the primary graphics surface assume a certain color.</para> + </listitem> + <listitem> + <para>A bitmap can be specified where each bit corresponds +to a pixel in the overlaid image. When the bit is set, the +corresponding video pixel is displayed, otherwise a pixel of the +graphics surface.</para> + </listitem> + <listitem> + <para>A list of clipping rectangles can be specified. In +these regions <emphasis>no</emphasis> video is displayed, so the +graphics surface can be seen here.</para> + </listitem> + <listitem> + <para>The framebuffer has an alpha channel that can be used +to clip or blend the framebuffer with the video.</para> + </listitem> + <listitem> + <para>A global alpha value can be specified to blend the +framebuffer contents with video images.</para> + </listitem> + </orderedlist></para> + + <para>When simultaneous capturing and overlay is supported and +the hardware prohibits different image and frame buffer formats, the +format requested first takes precedence. The attempt to capture +(&VIDIOC-S-FMT;) or overlay (&VIDIOC-S-FBUF;) may fail with an +&EBUSY; or return accordingly modified parameters..</para> + </section> + + <section> + <title>Overlay Window</title> + + <para>The overlaid image is determined by cropping and overlay +window parameters. The former select an area of the video picture to +capture, the latter how images are overlaid and clipped. Cropping +initialization at minimum requires to reset the parameters to +defaults. An example is given in <xref linkend="crop" />.</para> + + <para>The overlay window is described by a &v4l2-window;. It +defines the size of the image, its position over the graphics surface +and the clipping to be applied. To get the current parameters +applications set the <structfield>type</structfield> field of a +&v4l2-format; to <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant> and +call the &VIDIOC-G-FMT; ioctl. The driver fills the +<structname>v4l2_window</structname> substructure named +<structfield>win</structfield>. It is not possible to retrieve a +previously programmed clipping list or bitmap.</para> + + <para>To program the overlay window applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, initialize the +<structfield>win</structfield> substructure and call the +&VIDIOC-S-FMT; ioctl. The driver adjusts the parameters against +hardware limits and returns the actual parameters as +<constant>VIDIOC_G_FMT</constant> does. Like +<constant>VIDIOC_S_FMT</constant>, the &VIDIOC-TRY-FMT; ioctl can be +used to learn about driver capabilities without actually changing +driver state. Unlike <constant>VIDIOC_S_FMT</constant> this also works +after the overlay has been enabled.</para> + + <para>The scaling factor of the overlaid image is implied by the +width and height given in &v4l2-window; and the size of the cropping +rectangle. For more information see <xref linkend="crop" />.</para> + + <para>When simultaneous capturing and overlay is supported and +the hardware prohibits different image and window sizes, the size +requested first takes precedence. The attempt to capture or overlay as +well (&VIDIOC-S-FMT;) may fail with an &EBUSY; or return accordingly +modified parameters.</para> + + <table pgwide="1" frame="none" id="v4l2-window"> + <title>struct <structname>v4l2_window</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-rect;</entry> + <entry><structfield>w</structfield></entry> + <entry>Size and position of the window relative to the +top, left corner of the frame buffer defined with &VIDIOC-S-FBUF;. The +window can extend the frame buffer width and height, the +<structfield>x</structfield> and <structfield>y</structfield> +coordinates can be negative, and it can lie completely outside the +frame buffer. The driver clips the window accordingly, or if that is +not possible, modifies its size and/or position.</entry> + </row> + <row> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry>Applications set this field to determine which +video field shall be overlaid, typically one of +<constant>V4L2_FIELD_ANY</constant> (0), +<constant>V4L2_FIELD_TOP</constant>, +<constant>V4L2_FIELD_BOTTOM</constant> or +<constant>V4L2_FIELD_INTERLACED</constant>. Drivers may have to choose +a different field order and return the actual setting here.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>chromakey</structfield></entry> + <entry>When chroma-keying has been negotiated with +&VIDIOC-S-FBUF; applications set this field to the desired pixel value +for the chroma key. The format is the same as the pixel format of the +framebuffer (&v4l2-framebuffer; +<structfield>fmt.pixelformat</structfield> field), with bytes in host +order. E. g. for <link +linkend="V4L2-PIX-FMT-BGR32"><constant>V4L2_PIX_FMT_BGR24</constant></link> +the value should be 0xRRGGBB on a little endian, 0xBBGGRR on a big +endian host.</entry> + </row> + <row> + <entry>&v4l2-clip; *</entry> + <entry><structfield>clips</structfield></entry> + <entry>When chroma-keying has <emphasis>not</emphasis> +been negotiated and &VIDIOC-G-FBUF; indicated this capability, +applications can set this field to point to an array of +clipping rectangles.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Like the window coordinates +<structfield>w</structfield>, clipping rectangles are defined relative +to the top, left corner of the frame buffer. However clipping +rectangles must not extend the frame buffer width and height, and they +must not overlap. If possible applications should merge adjacent +rectangles. Whether this must create x-y or y-x bands, or the order of +rectangles, is not defined. When clip lists are not supported the +driver ignores this field. Its contents after calling &VIDIOC-S-FMT; +are undefined.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>clipcount</structfield></entry> + <entry>When the application set the +<structfield>clips</structfield> field, this field must contain the +number of clipping rectangles in the list. When clip lists are not +supported the driver ignores this field, its contents after calling +<constant>VIDIOC_S_FMT</constant> are undefined. When clip lists are +supported but no clipping is desired this field must be set to +zero.</entry> + </row> + <row> + <entry>void *</entry> + <entry><structfield>bitmap</structfield></entry> + <entry>When chroma-keying has +<emphasis>not</emphasis> been negotiated and &VIDIOC-G-FBUF; indicated +this capability, applications can set this field to point to a +clipping bit mask.</entry> + </row> + <row> + <entry spanname="hspan"><para>It must be of the same size +as the window, <structfield>w.width</structfield> and +<structfield>w.height</structfield>. Each bit corresponds to a pixel +in the overlaid image, which is displayed only when the bit is +<emphasis>set</emphasis>. Pixel coordinates translate to bits like: +<programlisting> +((__u8 *) <structfield>bitmap</structfield>)[<structfield>w.width</structfield> * y + x / 8] & (1 << (x & 7))</programlisting></para><para>where <structfield>0</structfield> ≤ x < +<structfield>w.width</structfield> and <structfield>0</structfield> ≤ +y <<structfield>w.height</structfield>.<footnote> + <para>Should we require + <structfield>w.width</structfield> to be a multiple of + eight?</para> + </footnote></para><para>When a clipping +bit mask is not supported the driver ignores this field, its contents +after calling &VIDIOC-S-FMT; are undefined. When a bit mask is supported +but no clipping is desired this field must be set to +<constant>NULL</constant>.</para><para>Applications need not create a +clip list or bit mask. When they pass both, or despite negotiating +chroma-keying, the results are undefined. Regardless of the chosen +method, the clipping abilities of the hardware may be limited in +quantity or quality. The results when these limits are exceeded are +undefined.<footnote> + <para>When the image is written into frame buffer +memory it will be undesirable if the driver clips out less pixels +than expected, because the application and graphics system are not +aware these regions need to be refreshed. The driver should clip out +more pixels or not write the image at all.</para> + </footnote></para></entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>global_alpha</structfield></entry> + <entry>The global alpha value used to blend the +framebuffer with video images, if global alpha blending has been +negotiated (<constant>V4L2_FBUF_FLAG_GLOBAL_ALPHA</constant>, see +&VIDIOC-S-FBUF;, <xref linkend="framebuffer-flags" />).</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Note this field was added in Linux 2.6.23, extending the structure. However +the <link linkend="vidioc-g-fmt">VIDIOC_G/S/TRY_FMT</link> ioctls, +which take a pointer to a <link +linkend="v4l2-format">v4l2_format</link> parent structure with padding +bytes at the end, are not affected.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-clip"> + <title>struct <structname>v4l2_clip</structname><footnote> + <para>The X Window system defines "regions" which are +vectors of struct BoxRec { short x1, y1, x2, y2; } with width = x2 - +x1 and height = y2 - y1, so one cannot pass X11 clip lists +directly.</para> + </footnote></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-rect;</entry> + <entry><structfield>c</structfield></entry> + <entry>Coordinates of the clipping rectangle, relative to +the top, left corner of the frame buffer. Only window pixels +<emphasis>outside</emphasis> all clipping rectangles are +displayed.</entry> + </row> + <row> + <entry>&v4l2-clip; *</entry> + <entry><structfield>next</structfield></entry> + <entry>Pointer to the next clipping rectangle, NULL when +this is the last rectangle. Drivers ignore this field, it cannot be +used to pass a linked list of clipping rectangles.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- NB for easier reading this table is duplicated + in the vidioc-cropcap chapter.--> + + <table pgwide="1" frame="none" id="v4l2-rect"> + <title>struct <structname>v4l2_rect</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__s32</entry> + <entry><structfield>left</structfield></entry> + <entry>Horizontal offset of the top, left corner of the +rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>top</structfield></entry> + <entry>Vertical offset of the top, left corner of the +rectangle, in pixels. Offsets increase to the right and down.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the rectangle, in pixels. Width and +height cannot be negative, the fields are signed for hysterical +reasons. <!-- video4linux-list@redhat.com on 22 Oct 2002 subject +"Re:[V4L][patches!] Re:v4l2/kernel-2.5" --></entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section> + <title>Enabling Overlay</title> + + <para>To start or stop the frame buffer overlay applications call +the &VIDIOC-OVERLAY; ioctl.</para> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-radio.xml b/Documentation/DocBook/v4l/dev-radio.xml new file mode 100644 index 0000000..73aa90b --- /dev/null +++ b/Documentation/DocBook/v4l/dev-radio.xml @@ -0,0 +1,57 @@ + <title>Radio Interface</title> + + <para>This interface is intended for AM and FM (analog) radio +receivers and transmitters.</para> + + <para>Conventionally V4L2 radio devices are accessed through +character device special files named <filename>/dev/radio</filename> +and <filename>/dev/radio0</filename> to +<filename>/dev/radio63</filename> with major number 81 and minor +numbers 64 to 127.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the radio interface set the +<constant>V4L2_CAP_RADIO</constant> and +<constant>V4L2_CAP_TUNER</constant> or +<constant>V4L2_CAP_MODULATOR</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. Other combinations of +capability flags are reserved for future extensions.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Radio devices can support <link +linkend="control">controls</link>, and must support the <link +linkend="tuner">tuner or modulator</link> ioctls.</para> + + <para>They do not support the video input or output, audio input +or output, video standard, cropping and scaling, compression and +streaming parameter, or overlay ioctls. All other ioctls and I/O +methods are reserved for future extensions.</para> + </section> + + <section> + <title>Programming</title> + + <para>Radio devices may have a couple audio controls (as discussed +in <xref linkend="control" />) such as a volume control, possibly custom +controls. Further all radio devices have one tuner or modulator (these are +discussed in <xref linkend="tuner" />) with index number zero to select +the radio frequency and to determine if a monaural or FM stereo +program is received/emitted. Drivers switch automatically between AM and FM +depending on the selected frequency. The &VIDIOC-G-TUNER; or +&VIDIOC-G-MODULATOR; ioctl +reports the supported frequency range.</para> + </section> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-raw-vbi.xml b/Documentation/DocBook/v4l/dev-raw-vbi.xml new file mode 100644 index 0000000..c5a70bd --- /dev/null +++ b/Documentation/DocBook/v4l/dev-raw-vbi.xml @@ -0,0 +1,347 @@ + <title>Raw VBI Data Interface</title> + + <para>VBI is an abbreviation of Vertical Blanking Interval, a gap +in the sequence of lines of an analog video signal. During VBI +no picture information is transmitted, allowing some time while the +electron beam of a cathode ray tube TV returns to the top of the +screen. Using an oscilloscope you will find here the vertical +synchronization pulses and short data packages ASK +modulated<footnote><para>ASK: Amplitude-Shift Keying. A high signal +level represents a '1' bit, a low level a '0' bit.</para></footnote> +onto the video signal. These are transmissions of services such as +Teletext or Closed Caption.</para> + + <para>Subject of this interface type is raw VBI data, as sampled off +a video signal, or to be added to a signal for output. +The data format is similar to uncompressed video images, a number of +lines times a number of samples per line, we call this a VBI image.</para> + + <para>Conventionally V4L2 VBI devices are accessed through character +device special files named <filename>/dev/vbi</filename> and +<filename>/dev/vbi0</filename> to <filename>/dev/vbi31</filename> with +major number 81 and minor numbers 224 to 255. +<filename>/dev/vbi</filename> is typically a symbolic link to the +preferred VBI device. This convention applies to both input and output +devices.</para> + + <para>To address the problems of finding related video and VBI +devices VBI capturing and output is also available as device function +under <filename>/dev/video</filename>. To capture or output raw VBI +data with these devices applications must call the &VIDIOC-S-FMT; +ioctl. Accessed as <filename>/dev/vbi</filename>, raw VBI capturing +or output is the default device function.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the raw VBI capturing or output API set +the <constant>V4L2_CAP_VBI_CAPTURE</constant> or +<constant>V4L2_CAP_VBI_OUTPUT</constant> flags, respectively, in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. At least one of the +read/write, streaming or asynchronous I/O methods must be +supported. VBI devices may or may not have a tuner or modulator.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>VBI devices shall support <link linkend="video">video +input or output</link>, <link linkend="tuner">tuner or +modulator</link>, and <link linkend="control">controls</link> ioctls +as needed. The <link linkend="standard">video standard</link> ioctls provide +information vital to program a VBI device, therefore must be +supported.</para> + </section> + + <section> + <title>Raw VBI Format Negotiation</title> + + <para>Raw VBI sampling abilities can vary, in particular the +sampling frequency. To properly interpret the data V4L2 specifies an +ioctl to query the sampling parameters. Moreover, to allow for some +flexibility applications can also suggest different parameters.</para> + + <para>As usual these parameters are <emphasis>not</emphasis> +reset at &func-open; time to permit Unix tool chains, programming a +device and then reading from it as if it was a plain file. Well +written V4L2 applications should always ensure they really get what +they want, requesting reasonable parameters and then checking if the +actual parameters are suitable.</para> + + <para>To query the current raw VBI capture parameters +applications set the <structfield>type</structfield> field of a +&v4l2-format; to <constant>V4L2_BUF_TYPE_VBI_CAPTURE</constant> or +<constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>, and call the +&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill +the &v4l2-vbi-format; <structfield>vbi</structfield> member of the +<structfield>fmt</structfield> union.</para> + + <para>To request different parameters applications set the +<structfield>type</structfield> field of a &v4l2-format; as above and +initialize all fields of the &v4l2-vbi-format; +<structfield>vbi</structfield> member of the +<structfield>fmt</structfield> union, or better just modify the +results of <constant>VIDIOC_G_FMT</constant>, and call the +&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers return +an &EINVAL; only when the given parameters are ambiguous, otherwise +they modify the parameters according to the hardware capabilites and +return the actual parameters. When the driver allocates resources at +this point, it may return an &EBUSY; to indicate the returned +parameters are valid but the required resources are currently not +available. That may happen for instance when the video and VBI areas +to capture would overlap, or when the driver supports multiple opens +and another process already requested VBI capturing or output. Anyway, +applications must expect other resource allocation points which may +return <errorcode>EBUSY</errorcode>, at the &VIDIOC-STREAMON; ioctl +and the first read(), write() and select() call.</para> + + <para>VBI devices must implement both the +<constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl, even if +<constant>VIDIOC_S_FMT</constant> ignores all requests and always +returns default parameters as <constant>VIDIOC_G_FMT</constant> does. +<constant>VIDIOC_TRY_FMT</constant> is optional.</para> + + <table pgwide="1" frame="none" id="v4l2-vbi-format"> + <title>struct <structname>v4l2_vbi_format</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>sampling_rate</structfield></entry> + <entry>Samples per second, i. e. unit 1 Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>offset</structfield></entry> + <entry><para>Horizontal offset of the VBI image, +relative to the leading edge of the line synchronization pulse and +counted in samples: The first sample in the VBI image will be located +<structfield>offset</structfield> / +<structfield>sampling_rate</structfield> seconds following the leading +edge. See also <xref linkend="vbi-hsync" />.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>samples_per_line</structfield></entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>sample_format</structfield></entry> + <entry><para>Defines the sample format as in <xref +linkend="pixfmt" />, a four-character-code.<footnote> + <para>A few devices may be unable to +sample VBI data at all but can extend the video capture window to the +VBI region.</para> + </footnote> Usually this is +<constant>V4L2_PIX_FMT_GREY</constant>, i. e. each sample +consists of 8 bits with lower values oriented towards the black level. +Do not assume any other correlation of values with the signal level. +For example, the MSB does not necessarily indicate if the signal is +'high' or 'low' because 128 may not be the mean value of the +signal. Drivers shall not convert the sample format by software.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>start</structfield>[2]</entry> + <entry>This is the scanning system line number +associated with the first line of the VBI image, of the first and the +second field respectively. See <xref linkend="vbi-525" /> and +<xref linkend="vbi-625" /> for valid values. VBI input drivers can +return start values 0 if the hardware cannot reliable identify +scanning lines, VBI acquisition may not require this +information.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>count</structfield>[2]</entry> + <entry>The number of lines in the first and second +field image, respectively.</entry> + </row> + <row> + <entry spanname="hspan"><para>Drivers should be as +flexibility as possible. For example, it may be possible to extend or +move the VBI capture window down to the picture area, implementing a +'full field mode' to capture data service transmissions embedded in +the picture.</para><para>An application can set the first or second +<structfield>count</structfield> value to zero if no data is required +from the respective field; <structfield>count</structfield>[1] if the +scanning system is progressive, &ie; not interlaced. The +corresponding start value shall be ignored by the application and +driver. Anyway, drivers may not support single field capturing and +return both count values non-zero.</para><para>Both +<structfield>count</structfield> values set to zero, or line numbers +outside the bounds depicted in <xref linkend="vbi-525" /> and <xref + linkend="vbi-625" />, or a field image covering +lines of two fields, are invalid and shall not be returned by the +driver.</para><para>To initialize the <structfield>start</structfield> +and <structfield>count</structfield> fields, applications must first +determine the current video standard selection. The &v4l2-std-id; or +the <structfield>framelines</structfield> field of &v4l2-standard; can +be evaluated for this purpose.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>See <xref linkend="vbifmt-flags" /> below. Currently +only drivers set flags, applications must set this field to +zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>This array is reserved for future extensions. +Drivers and applications must set it to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="vbifmt-flags"> + <title>Raw VBI Format Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_VBI_UNSYNC</constant></entry> + <entry>0x0001</entry> + <entry><para>This flag indicates hardware which does not +properly distinguish between fields. Normally the VBI image stores the +first field (lower scanning line numbers) first in memory. This may be +a top or bottom field depending on the video standard. When this flag +is set the first or second field may be stored first, however the +fields are still in correct temporal order with the older field first +in memory.<footnote> + <para>Most VBI services transmit on both fields, but +some have different semantics depending on the field number. These +cannot be reliable decoded or encoded when +<constant>V4L2_VBI_UNSYNC</constant> is set.</para> + </footnote></para></entry> + </row> + <row> + <entry><constant>V4L2_VBI_INTERLACED</constant></entry> + <entry>0x0002</entry> + <entry>By default the two field images will be passed +sequentially; all lines of the first field followed by all lines of +the second field (compare <xref linkend="field-order" /> +<constant>V4L2_FIELD_SEQ_TB</constant> and +<constant>V4L2_FIELD_SEQ_BT</constant>, whether the top or bottom +field is first in memory depends on the video standard). When this +flag is set, the two fields are interlaced (cf. +<constant>V4L2_FIELD_INTERLACED</constant>). The first line of the +first field followed by the first line of the second field, then the +two second lines, and so on. Such a layout may be necessary when the +hardware has been programmed to capture or output interlaced video +images and is unable to separate the fields for VBI capturing at +the same time. For simplicity setting this flag implies that both +<structfield>count</structfield> values are equal and non-zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <figure id="vbi-hsync"> + <title>Line synchronization</title> + <mediaobject> + <imageobject> + <imagedata fileref="vbi_hsync.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="vbi_hsync.gif" format="GIF" /> + </imageobject> + <textobject> + <phrase>Line synchronization diagram</phrase> + </textobject> + </mediaobject> + </figure> + + <figure id="vbi-525"> + <title>ITU-R 525 line numbering (M/NTSC and M/PAL)</title> + <mediaobject> + <imageobject> + <imagedata fileref="vbi_525.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="vbi_525.gif" format="GIF" /> + </imageobject> + <textobject> + <phrase>NTSC field synchronization diagram</phrase> + </textobject> + <caption> + <para>(1) For the purpose of this specification field 2 +starts in line 264 and not 263.5 because half line capturing is not +supported.</para> + </caption> + </mediaobject> + </figure> + + <figure id="vbi-625"> + <title>ITU-R 625 line numbering</title> + <mediaobject> + <imageobject> + <imagedata fileref="vbi_625.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="vbi_625.gif" format="GIF" /> + </imageobject> + <textobject> + <phrase>PAL/SECAM field synchronization diagram</phrase> + </textobject> + <caption> + <para>(1) For the purpose of this specification field 2 +starts in line 314 and not 313.5 because half line capturing is not +supported.</para> + </caption> + </mediaobject> + </figure> + + <para>Remember the VBI image format depends on the selected +video standard, therefore the application must choose a new standard or +query the current standard first. Attempts to read or write data ahead +of format negotiation, or after switching the video standard which may +invalidate the negotiated VBI parameters, should be refused by the +driver. A format change during active I/O is not permitted.</para> + </section> + + <section> + <title>Reading and writing VBI images</title> + + <para>To assure synchronization with the field number and easier +implementation, the smallest unit of data passed at a time is one +frame, consisting of two fields of VBI images immediately following in +memory.</para> + + <para>The total size of a frame computes as follows:</para> + + <programlisting> +(<structfield>count</structfield>[0] + <structfield>count</structfield>[1]) * +<structfield>samples_per_line</structfield> * sample size in bytes</programlisting> + + <para>The sample size is most likely always one byte, +applications must check the <structfield>sample_format</structfield> +field though, to function properly with other drivers.</para> + + <para>A VBI device may support <link + linkend="rw">read/write</link> and/or streaming (<link + linkend="mmap">memory mapping</link> or <link + linkend="userp">user pointer</link>) I/O. The latter bears the +possibility of synchronizing video and +VBI data by using buffer timestamps.</para> + + <para>Remember the &VIDIOC-STREAMON; ioctl and the first read(), +write() and select() call can be resource allocation points returning +an &EBUSY; if the required hardware resources are temporarily +unavailable, for example the device is already in use by another +process.</para> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-rds.xml b/Documentation/DocBook/v4l/dev-rds.xml new file mode 100644 index 0000000..0869d70 --- /dev/null +++ b/Documentation/DocBook/v4l/dev-rds.xml @@ -0,0 +1,168 @@ + <title>RDS Interface</title> + + <para>The Radio Data System transmits supplementary +information in binary format, for example the station name or travel +information, on an inaudible audio subcarrier of a radio program. This +interface is aimed at devices capable of receiving and decoding RDS +information.</para> + + <para>For more information see the core RDS standard <xref linkend="en50067" /> +and the RBDS standard <xref linkend="nrsc4" />.</para> + + <para>Note that the RBDS standard as is used in the USA is almost identical +to the RDS standard. Any RDS decoder can also handle RBDS. Only some of the fields +have slightly different meanings. See the RBDS standard for more information.</para> + + <para>The RBDS standard also specifies support for MMBS (Modified Mobile Search). +This is a proprietary format which seems to be discontinued. The RDS interface does not +support this format. Should support for MMBS (or the so-called 'E blocks' in general) +be needed, then please contact the linux-media mailing list: &v4l-ml;.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the RDS capturing API +set the <constant>V4L2_CAP_RDS_CAPTURE</constant> flag in +the <structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. +Any tuner that supports RDS will set the +<constant>V4L2_TUNER_CAP_RDS</constant> flag in the <structfield>capability</structfield> +field of &v4l2-tuner;. +Whether an RDS signal is present can be detected by looking at +the <structfield>rxsubchans</structfield> field of &v4l2-tuner;: the +<constant>V4L2_TUNER_SUB_RDS</constant> will be set if RDS data was detected.</para> + + <para>Devices supporting the RDS output API +set the <constant>V4L2_CAP_RDS_OUTPUT</constant> flag in +the <structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. +Any modulator that supports RDS will set the +<constant>V4L2_TUNER_CAP_RDS</constant> flag in the <structfield>capability</structfield> +field of &v4l2-modulator;. +In order to enable the RDS transmission one must set the <constant>V4L2_TUNER_SUB_RDS</constant> +bit in the <structfield>txsubchans</structfield> field of &v4l2-modulator;.</para> + + </section> + + <section> + <title>Reading RDS data</title> + + <para>RDS data can be read from the radio device +with the &func-read; function. The data is packed in groups of three bytes, +as follows:</para> + <table frame="none" pgwide="1" id="v4l2-rds-data"> + <title>struct +<structname>v4l2_rds_data</structname></title> + <tgroup cols="3"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="5*" /> + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>lsb</structfield></entry> + <entry>Least Significant Byte of RDS Block</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>msb</structfield></entry> + <entry>Most Significant Byte of RDS Block</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>block</structfield></entry> + <entry>Block description</entry> + </row> + </tbody> + </tgroup> + </table> + <table frame="none" pgwide="1" id="v4l2-rds-block"> + <title>Block description</title> + <tgroup cols="2"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="5*" /> + <tbody valign="top"> + <row> + <entry>Bits 0-2</entry> + <entry>Block (aka offset) of the received data.</entry> + </row> + <row> + <entry>Bits 3-5</entry> + <entry>Deprecated. Currently identical to bits 0-2. Do not use these bits.</entry> + </row> + <row> + <entry>Bit 6</entry> + <entry>Corrected bit. Indicates that an error was corrected for this data block.</entry> + </row> + <row> + <entry>Bit 7</entry> + <entry>Error bit. Indicates that an uncorrectable error occurred during reception of this block.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-rds-block-codes"> + <title>Block defines</title> + <tgroup cols="3"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="5*" /> + <tbody valign="top"> + <row> + <entry>V4L2_RDS_BLOCK_MSK</entry> + <entry>7</entry> + <entry>Mask for bits 0-2 to get the block ID.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_A</entry> + <entry>0</entry> + <entry>Block A.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_B</entry> + <entry>1</entry> + <entry>Block B.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_C</entry> + <entry>2</entry> + <entry>Block C.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_D</entry> + <entry>3</entry> + <entry>Block D.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_C_ALT</entry> + <entry>4</entry> + <entry>Block C'.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_INVALID</entry> + <entry>7</entry> + <entry>An invalid block.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_CORRECTED</entry> + <entry>0x40</entry> + <entry>A bit error was detected but corrected.</entry> + </row> + <row> + <entry>V4L2_RDS_BLOCK_ERROR</entry> + <entry>0x80</entry> + <entry>An incorrectable error occurred.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-sliced-vbi.xml b/Documentation/DocBook/v4l/dev-sliced-vbi.xml new file mode 100644 index 0000000..69e789f --- /dev/null +++ b/Documentation/DocBook/v4l/dev-sliced-vbi.xml @@ -0,0 +1,708 @@ + <title>Sliced VBI Data Interface</title> + + <para>VBI stands for Vertical Blanking Interval, a gap in the +sequence of lines of an analog video signal. During VBI no picture +information is transmitted, allowing some time while the electron beam +of a cathode ray tube TV returns to the top of the screen.</para> + + <para>Sliced VBI devices use hardware to demodulate data transmitted +in the VBI. V4L2 drivers shall <emphasis>not</emphasis> do this by +software, see also the <link linkend="raw-vbi">raw VBI +interface</link>. The data is passed as short packets of fixed size, +covering one scan line each. The number of packets per video frame is +variable.</para> + + <para>Sliced VBI capture and output devices are accessed through the +same character special files as raw VBI devices. When a driver +supports both interfaces, the default function of a +<filename>/dev/vbi</filename> device is <emphasis>raw</emphasis> VBI +capturing or output, and the sliced VBI function is only available +after calling the &VIDIOC-S-FMT; ioctl as defined below. Likewise a +<filename>/dev/video</filename> device may support the sliced VBI API, +however the default function here is video capturing or output. +Different file descriptors must be used to pass raw and sliced VBI +data simultaneously, if this is supported by the driver.</para> + + <section> + <title>Querying Capabilities</title> + + <para>Devices supporting the sliced VBI capturing or output API +set the <constant>V4L2_CAP_SLICED_VBI_CAPTURE</constant> or +<constant>V4L2_CAP_SLICED_VBI_OUTPUT</constant> flag respectively, in +the <structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. At least one of the +read/write, streaming or asynchronous <link linkend="io">I/O +methods</link> must be supported. Sliced VBI devices may have a tuner +or modulator.</para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para>Sliced VBI devices shall support <link linkend="video">video +input or output</link> and <link linkend="tuner">tuner or +modulator</link> ioctls if they have these capabilities, and they may +support <link linkend="control">control</link> ioctls. The <link +linkend="standard">video standard</link> ioctls provide information +vital to program a sliced VBI device, therefore must be +supported.</para> + </section> + + <section id="sliced-vbi-format-negotitation"> + <title>Sliced VBI Format Negotiation</title> + + <para>To find out which data services are supported by the +hardware applications can call the &VIDIOC-G-SLICED-VBI-CAP; ioctl. +All drivers implementing the sliced VBI interface must support this +ioctl. The results may differ from those of the &VIDIOC-S-FMT; ioctl +when the number of VBI lines the hardware can capture or output per +frame, or the number of services it can identify on a given line are +limited. For example on PAL line 16 the hardware may be able to look +for a VPS or Teletext signal, but not both at the same time.</para> + + <para>To determine the currently selected services applications +set the <structfield>type </structfield> field of &v4l2-format; to +<constant> V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> or <constant> +V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant>, and the &VIDIOC-G-FMT; +ioctl fills the <structfield>fmt.sliced</structfield> member, a +&v4l2-sliced-vbi-format;.</para> + + <para>Applications can request different parameters by +initializing or modifying the <structfield>fmt.sliced</structfield> +member and calling the &VIDIOC-S-FMT; ioctl with a pointer to the +<structname>v4l2_format</structname> structure.</para> + + <para>The sliced VBI API is more complicated than the raw VBI API +because the hardware must be told which VBI service to expect on each +scan line. Not all services may be supported by the hardware on all +lines (this is especially true for VBI output where Teletext is often +unsupported and other services can only be inserted in one specific +line). In many cases, however, it is sufficient to just set the +<structfield>service_set</structfield> field to the required services +and let the driver fill the <structfield>service_lines</structfield> +array according to hardware capabilities. Only if more precise control +is needed should the programmer set the +<structfield>service_lines</structfield> array explicitly.</para> + + <para>The &VIDIOC-S-FMT; ioctl modifies the parameters +according to hardware capabilities. When the driver allocates +resources at this point, it may return an &EBUSY; if the required +resources are temporarily unavailable. Other resource allocation +points which may return <errorcode>EBUSY</errorcode> can be the +&VIDIOC-STREAMON; ioctl and the first &func-read;, &func-write; and +&func-select; call.</para> + + <table frame="none" pgwide="1" id="v4l2-sliced-vbi-format"> + <title>struct +<structname>v4l2_sliced_vbi_format</structname></title> + <tgroup cols="5"> + <colspec colname="c1" colwidth="3*" /> + <colspec colname="c2" colwidth="3*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="2*" /> + <colspec colname="c5" colwidth="2*" /> + <spanspec namest="c3" nameend="c5" spanname="hspan" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>service_set</structfield></entry> + <entry spanname="hspan"><para>If +<structfield>service_set</structfield> is non-zero when passed with +&VIDIOC-S-FMT; or &VIDIOC-TRY-FMT;, the +<structfield>service_lines</structfield> array will be filled by the +driver according to the services specified in this field. For example, +if <structfield>service_set</structfield> is initialized with +<constant>V4L2_SLICED_TELETEXT_B | V4L2_SLICED_WSS_625</constant>, a +driver for the cx25840 video decoder sets lines 7-22 of both +fields<footnote><para>According to <link +linkend="ets300706">ETS 300 706</link> lines 6-22 of the +first field and lines 5-22 of the second field may carry Teletext +data.</para></footnote> to <constant>V4L2_SLICED_TELETEXT_B</constant> +and line 23 of the first field to +<constant>V4L2_SLICED_WSS_625</constant>. If +<structfield>service_set</structfield> is set to zero, then the values +of <structfield>service_lines</structfield> will be used instead. +</para><para>On return the driver sets this field to the union of all +elements of the returned <structfield>service_lines</structfield> +array. It may contain less services than requested, perhaps just one, +if the hardware cannot handle more services simultaneously. It may be +empty (zero) if none of the requested services are supported by the +hardware.</para></entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>service_lines</structfield>[2][24]</entry> + <entry spanname="hspan"><para>Applications initialize this +array with sets of data services the driver shall look for or insert +on the respective scan line. Subject to hardware capabilities drivers +return the requested set, a subset, which may be just a single +service, or an empty set. When the hardware cannot handle multiple +services on the same line the driver shall choose one. No assumptions +can be made on which service the driver chooses.</para><para>Data +services are defined in <xref linkend="vbi-services2" />. Array indices +map to ITU-R line numbers (see also <xref linkend="vbi-525" /> and <xref + linkend="vbi-625" />) as follows: <!-- No nested +tables, sigh. --></para></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Element</entry> + <entry>525 line systems</entry> + <entry>625 line systems</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[0][1]</entry> + <entry align="center">1</entry> + <entry align="center">1</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[0][23]</entry> + <entry align="center">23</entry> + <entry align="center">23</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[1][1]</entry> + <entry align="center">264</entry> + <entry align="center">314</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[1][23]</entry> + <entry align="center">286</entry> + <entry align="center">336</entry> + </row> + <!-- End of line numbers table. --> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan">Drivers must set +<structfield>service_lines</structfield>[0][0] and +<structfield>service_lines</structfield>[1][0] to zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>io_size</structfield></entry> + <entry spanname="hspan">Maximum number of bytes passed by +one &func-read; or &func-write; call, and the buffer size in bytes for +the &VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl. Drivers set this field to +the size of &v4l2-sliced-vbi-data; times the number of non-zero +elements in the returned <structfield>service_lines</structfield> +array (that is the number of lines potentially carrying data).</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry spanname="hspan">This array is reserved for future +extensions. Applications and drivers must set it to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- See also vidioc-g-sliced-vbi-cap.sgml --> + <table frame="none" pgwide="1" id="vbi-services2"> + <title>Sliced VBI services</title> + <tgroup cols="5"> + <colspec colname="c1" colwidth="2*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="1*" /> + <colspec colname="c4" colwidth="2*" /> + <colspec colname="c5" colwidth="2*" /> + <spanspec namest="c3" nameend="c5" spanname="rlp" /> + <thead> + <row> + <entry>Symbol</entry> + <entry>Value</entry> + <entry>Reference</entry> + <entry>Lines, usually</entry> + <entry>Payload</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_SLICED_TELETEXT_B</constant> +(Teletext System B)</entry> + <entry>0x0001</entry> + <entry><xref linkend="ets300706" />, <xref linkend="itu653" /></entry> + <entry>PAL/SECAM line 7-22, 320-335 (second field 7-22)</entry> + <entry>Last 42 of the 45 byte Teletext packet, that is +without clock run-in and framing code, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VPS</constant></entry> + <entry>0x0400</entry> + <entry><xref linkend="ets300231" /></entry> + <entry>PAL line 16</entry> + <entry>Byte number 3 to 15 according to Figure 9 of +ETS 300 231, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_CAPTION_525</constant></entry> + <entry>0x1000</entry> + <entry><xref linkend="eia608" /></entry> + <entry>NTSC line 21, 284 (second field 21)</entry> + <entry>Two bytes in transmission order, including parity +bit, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_WSS_625</constant></entry> + <entry>0x4000</entry> + <entry><xref linkend="itu1119" />, <xref linkend="en300294" /></entry> + <entry>PAL/SECAM line 23</entry> + <entry><screen> +Byte 0 1 + msb lsb msb lsb + Bit 7 6 5 4 3 2 1 0 x x 13 12 11 10 9 +</screen></entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VBI_525</constant></entry> + <entry>0x1000</entry> + <entry spanname="rlp">Set of services applicable to 525 +line systems.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VBI_625</constant></entry> + <entry>0x4401</entry> + <entry spanname="rlp">Set of services applicable to 625 +line systems.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Drivers may return an &EINVAL; when applications attempt to +read or write data without prior format negotiation, after switching +the video standard (which may invalidate the negotiated VBI +parameters) and after switching the video input (which may change the +video standard as a side effect). The &VIDIOC-S-FMT; ioctl may return +an &EBUSY; when applications attempt to change the format while i/o is +in progress (between a &VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; call, +and after the first &func-read; or &func-write; call).</para> + </section> + + <section> + <title>Reading and writing sliced VBI data</title> + + <para>A single &func-read; or &func-write; call must pass all data +belonging to one video frame. That is an array of +<structname>v4l2_sliced_vbi_data</structname> structures with one or +more elements and a total size not exceeding +<structfield>io_size</structfield> bytes. Likewise in streaming I/O +mode one buffer of <structfield>io_size</structfield> bytes must +contain data of one video frame. The <structfield>id</structfield> of +unused <structname>v4l2_sliced_vbi_data</structname> elements must be +zero.</para> + + <table frame="none" pgwide="1" id="v4l2-sliced-vbi-data"> + <title>struct +<structname>v4l2_sliced_vbi_data</structname></title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>A flag from <xref linkend="vbi-services" /> +identifying the type of data in this packet. Only a single bit must be +set. When the <structfield>id</structfield> of a captured packet is +zero, the packet is empty and the contents of other fields are +undefined. Applications shall ignore empty packets. When the +<structfield>id</structfield> of a packet for output is zero the +contents of the <structfield>data</structfield> field are undefined +and the driver must no longer insert data on the requested +<structfield>field</structfield> and +<structfield>line</structfield>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>field</structfield></entry> + <entry>The video field number this data has been captured +from, or shall be inserted at. <constant>0</constant> for the first +field, <constant>1</constant> for the second field.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>line</structfield></entry> + <entry>The field (as opposed to frame) line number this +data has been captured from, or shall be inserted at. See <xref + linkend="vbi-525" /> and <xref linkend="vbi-625" /> for valid +values. Sliced VBI capture devices can set the line number of all +packets to <constant>0</constant> if the hardware cannot reliably +identify scan lines. The field number must always be valid.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield></entry> + <entry>This field is reserved for future extensions. +Applications and drivers must set it to zero.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>data</structfield>[48]</entry> + <entry>The packet payload. See <xref + linkend="vbi-services" /> for the contents and number of +bytes passed for each data type. The contents of padding bytes at the +end of this array are undefined, drivers and applications shall ignore +them.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Packets are always passed in ascending line number order, +without duplicate line numbers. The &func-write; function and the +&VIDIOC-QBUF; ioctl must return an &EINVAL; when applications violate +this rule. They must also return an &EINVAL; when applications pass an +incorrect field or line number, or a combination of +<structfield>field</structfield>, <structfield>line</structfield> and +<structfield>id</structfield> which has not been negotiated with the +&VIDIOC-G-FMT; or &VIDIOC-S-FMT; ioctl. When the line numbers are +unknown the driver must pass the packets in transmitted order. The +driver can insert empty packets with <structfield>id</structfield> set +to zero anywhere in the packet array.</para> + + <para>To assure synchronization and to distinguish from frame +dropping, when a captured frame does not carry any of the requested +data services drivers must pass one or more empty packets. When an +application fails to pass VBI data in time for output, the driver +must output the last VPS and WSS packet again, and disable the output +of Closed Caption and Teletext data, or output data which is ignored +by Closed Caption and Teletext decoders.</para> + + <para>A sliced VBI device may support <link +linkend="rw">read/write</link> and/or streaming (<link +linkend="mmap">memory mapping</link> and/or <link linkend="userp">user +pointer</link>) I/O. The latter bears the possibility of synchronizing +video and VBI data by using buffer timestamps.</para> + + </section> + + <section> + <title>Sliced VBI Data in MPEG Streams</title> + + <para>If a device can produce an MPEG output stream, it may be +capable of providing <link +linkend="sliced-vbi-format-negotitation">negotiated sliced VBI +services</link> as data embedded in the MPEG stream. Users or +applications control this sliced VBI data insertion with the <link +linkend="v4l2-mpeg-stream-vbi-fmt">V4L2_CID_MPEG_STREAM_VBI_FMT</link> +control.</para> + + <para>If the driver does not provide the <link +linkend="v4l2-mpeg-stream-vbi-fmt">V4L2_CID_MPEG_STREAM_VBI_FMT</link> +control, or only allows that control to be set to <link +linkend="v4l2-mpeg-stream-vbi-fmt"><constant> +V4L2_MPEG_STREAM_VBI_FMT_NONE</constant></link>, then the device +cannot embed sliced VBI data in the MPEG stream.</para> + + <para>The <link linkend="v4l2-mpeg-stream-vbi-fmt"> +V4L2_CID_MPEG_STREAM_VBI_FMT</link> control does not implicitly set +the device driver to capture nor cease capturing sliced VBI data. The +control only indicates to embed sliced VBI data in the MPEG stream, if +an application has negotiated sliced VBI service be captured.</para> + + <para>It may also be the case that a device can embed sliced VBI +data in only certain types of MPEG streams: for example in an MPEG-2 +PS but not an MPEG-2 TS. In this situation, if sliced VBI data +insertion is requested, the sliced VBI data will be embedded in MPEG +stream types when supported, and silently omitted from MPEG stream +types where sliced VBI data insertion is not supported by the device. +</para> + + <para>The following subsections specify the format of the +embedded sliced VBI data.</para> + + <section> + <title>MPEG Stream Embedded, Sliced VBI Data Format: NONE</title> + <para>The <link linkend="v4l2-mpeg-stream-vbi-fmt"><constant> +V4L2_MPEG_STREAM_VBI_FMT_NONE</constant></link> embedded sliced VBI +format shall be interpreted by drivers as a control to cease +embedding sliced VBI data in MPEG streams. Neither the device nor +driver shall insert "empty" embedded sliced VBI data packets in the +MPEG stream when this format is set. No MPEG stream data structures +are specified for this format.</para> + </section> + + <section> + <title>MPEG Stream Embedded, Sliced VBI Data Format: IVTV</title> + <para>The <link linkend="v4l2-mpeg-stream-vbi-fmt"><constant> +V4L2_MPEG_STREAM_VBI_FMT_IVTV</constant></link> embedded sliced VBI +format, when supported, indicates to the driver to embed up to 36 +lines of sliced VBI data per frame in an MPEG-2 <emphasis>Private +Stream 1 PES</emphasis> packet encapsulated in an MPEG-2 <emphasis> +Program Pack</emphasis> in the MPEG stream.</para> + + <para><emphasis>Historical context</emphasis>: This format +specification originates from a custom, embedded, sliced VBI data +format used by the <filename>ivtv</filename> driver. This format +has already been informally specified in the kernel sources in the +file <filename>Documentation/video4linux/cx2341x/README.vbi</filename> +. The maximum size of the payload and other aspects of this format +are driven by the CX23415 MPEG decoder's capabilities and limitations +with respect to extracting, decoding, and displaying sliced VBI data +embedded within an MPEG stream.</para> + + <para>This format's use is <emphasis>not</emphasis> exclusive to +the <filename>ivtv</filename> driver <emphasis>nor</emphasis> +exclusive to CX2341x devices, as the sliced VBI data packet insertion +into the MPEG stream is implemented in driver software. At least the +<filename>cx18</filename> driver provides sliced VBI data insertion +into an MPEG-2 PS in this format as well.</para> + + <para>The following definitions specify the payload of the +MPEG-2 <emphasis>Private Stream 1 PES</emphasis> packets that contain +sliced VBI data when <link linkend="v4l2-mpeg-stream-vbi-fmt"> +<constant>V4L2_MPEG_STREAM_VBI_FMT_IVTV</constant></link> is set. +(The MPEG-2 <emphasis>Private Stream 1 PES</emphasis> packet header +and encapsulating MPEG-2 <emphasis>Program Pack</emphasis> header are +not detailed here. Please refer to the MPEG-2 specifications for +details on those packet headers.)</para> + + <para>The payload of the MPEG-2 <emphasis>Private Stream 1 PES +</emphasis> packets that contain sliced VBI data is specified by +&v4l2-mpeg-vbi-fmt-ivtv;. The payload is variable +length, depending on the actual number of lines of sliced VBI data +present in a video frame. The payload may be padded at the end with +unspecified fill bytes to align the end of the payload to a 4-byte +boundary. The payload shall never exceed 1552 bytes (2 fields with +18 lines/field with 43 bytes of data/line and a 4 byte magic number). +</para> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-fmt-ivtv"> + <title>struct <structname>v4l2_mpeg_vbi_fmt_ivtv</structname> + </title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>magic</structfield>[4]</entry> + <entry></entry> + <entry>A "magic" constant from <xref + linkend="v4l2-mpeg-vbi-fmt-ivtv-magic" /> that indicates +this is a valid sliced VBI data payload and also indicates which +member of the anonymous union, <structfield>itv0</structfield> or +<structfield>ITV0</structfield>, to use for the payload data.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>struct <link linkend="v4l2-mpeg-vbi-itv0"> + <structname>v4l2_mpeg_vbi_itv0</structname></link> + </entry> + <entry><structfield>itv0</structfield></entry> + <entry>The primary form of the sliced VBI data payload +that contains anywhere from 1 to 35 lines of sliced VBI data. +Line masks are provided in this form of the payload indicating +which VBI lines are provided.</entry> + </row> + <row> + <entry></entry> + <entry>struct <link linkend="v4l2-mpeg-vbi-itv0-1"> + <structname>v4l2_mpeg_vbi_ITV0</structname></link> + </entry> + <entry><structfield>ITV0</structfield></entry> + <entry>An alternate form of the sliced VBI data payload +used when 36 lines of sliced VBI data are present. No line masks are +provided in this form of the payload; all valid line mask bits are +implcitly set.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-fmt-ivtv-magic"> + <title>Magic Constants for &v4l2-mpeg-vbi-fmt-ivtv; + <structfield>magic</structfield> field</title> + <tgroup cols="3"> + &cs-def; + <thead> + <row> + <entry align="left">Defined Symbol</entry> + <entry align="left">Value</entry> + <entry align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_MAGIC0</constant> + </entry> + <entry>"itv0"</entry> + <entry>Indicates the <structfield>itv0</structfield> +member of the union in &v4l2-mpeg-vbi-fmt-ivtv; is valid.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_MAGIC1</constant> + </entry> + <entry>"ITV0"</entry> + <entry>Indicates the <structfield>ITV0</structfield> +member of the union in &v4l2-mpeg-vbi-fmt-ivtv; is valid and +that 36 lines of sliced VBI data are present.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-itv0"> + <title>struct <structname>v4l2_mpeg_vbi_itv0</structname> + </title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__le32</entry> + <entry><structfield>linemask</structfield>[2]</entry> + <entry><para>Bitmasks indicating the VBI service lines +present. These <structfield>linemask</structfield> values are stored +in little endian byte order in the MPEG stream. Some reference +<structfield>linemask</structfield> bit positions with their +corresponding VBI line number and video field are given below. +b<subscript>0</subscript> indicates the least significant bit of a +<structfield>linemask</structfield> value:<screen> +<structfield>linemask</structfield>[0] b<subscript>0</subscript>: line 6 first field +<structfield>linemask</structfield>[0] b<subscript>17</subscript>: line 23 first field +<structfield>linemask</structfield>[0] b<subscript>18</subscript>: line 6 second field +<structfield>linemask</structfield>[0] b<subscript>31</subscript>: line 19 second field +<structfield>linemask</structfield>[1] b<subscript>0</subscript>: line 20 second field +<structfield>linemask</structfield>[1] b<subscript>3</subscript>: line 23 second field +<structfield>linemask</structfield>[1] b<subscript>4</subscript>-b<subscript>31</subscript>: unused and set to 0</screen></para></entry> + </row> + <row> + <entry>struct <link linkend="v4l2-mpeg-vbi-itv0-line"> + <structname>v4l2_mpeg_vbi_itv0_line</structname></link> + </entry> + <entry><structfield>line</structfield>[35]</entry> + <entry>This is a variable length array that holds from 1 +to 35 lines of sliced VBI data. The sliced VBI data lines present +correspond to the bits set in the <structfield>linemask</structfield> +array, starting from b<subscript>0</subscript> of <structfield> +linemask</structfield>[0] up through b<subscript>31</subscript> of +<structfield>linemask</structfield>[0], and from b<subscript>0 +</subscript> of <structfield>linemask</structfield>[1] up through b +<subscript>3</subscript> of <structfield>linemask</structfield>[1]. +<structfield>line</structfield>[0] corresponds to the first bit +found set in the <structfield>linemask</structfield> array, +<structfield>line</structfield>[1] corresponds to the second bit +found set in the <structfield>linemask</structfield> array, etc. +If no <structfield>linemask</structfield> array bits are set, then +<structfield>line</structfield>[0] may contain one line of +unspecified data that should be ignored by applications.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-itv0-1"> + <title>struct <structname>v4l2_mpeg_vbi_ITV0</structname> + </title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>struct <link linkend="v4l2-mpeg-vbi-itv0-line"> + <structname>v4l2_mpeg_vbi_itv0_line</structname></link> + </entry> + <entry><structfield>line</structfield>[36]</entry> + <entry>A fixed length array of 36 lines of sliced VBI +data. <structfield>line</structfield>[0] through <structfield>line +</structfield>[17] correspond to lines 6 through 23 of the +first field. <structfield>line</structfield>[18] through +<structfield>line</structfield>[35] corresponds to lines 6 +through 23 of the second field.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-mpeg-vbi-itv0-line"> + <title>struct <structname>v4l2_mpeg_vbi_itv0_line</structname> + </title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>id</structfield></entry> + <entry>A line identifier value from +<xref linkend="ITV0-Line-Identifier-Constants" /> that indicates +the type of sliced VBI data stored on this line.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>data</structfield>[42]</entry> + <entry>The sliced VBI data for the line.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="ITV0-Line-Identifier-Constants"> + <title>Line Identifiers for struct <link + linkend="v4l2-mpeg-vbi-itv0-line"><structname> +v4l2_mpeg_vbi_itv0_line</structname></link> <structfield>id +</structfield> field</title> + <tgroup cols="3"> + &cs-def; + <thead> + <row> + <entry align="left">Defined Symbol</entry> + <entry align="left">Value</entry> + <entry align="left">Description</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_TELETEXT_B</constant> + </entry> + <entry>1</entry> + <entry>Refer to <link linkend="vbi-services2"> +Sliced VBI services</link> for a description of the line payload.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_CAPTION_525</constant> + </entry> + <entry>4</entry> + <entry>Refer to <link linkend="vbi-services2"> +Sliced VBI services</link> for a description of the line payload.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_WSS_625</constant> + </entry> + <entry>5</entry> + <entry>Refer to <link linkend="vbi-services2"> +Sliced VBI services</link> for a description of the line payload.</entry> + </row> + <row> + <entry><constant>V4L2_MPEG_VBI_IVTV_VPS</constant> + </entry> + <entry>7</entry> + <entry>Refer to <link linkend="vbi-services2"> +Sliced VBI services</link> for a description of the line payload.</entry> + </row> + </tbody> + </tgroup> + </table> + + </section> + </section> + + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/dev-teletext.xml b/Documentation/DocBook/v4l/dev-teletext.xml new file mode 100644 index 0000000..59f9993 --- /dev/null +++ b/Documentation/DocBook/v4l/dev-teletext.xml @@ -0,0 +1,40 @@ + <title>Teletext Interface</title> + + <para>This interface aims at devices receiving and demodulating +Teletext data [<xref linkend="ets300706" />, <xref linkend="itu653" />], evaluating the +Teletext packages and storing formatted pages in cache memory. Such +devices are usually implemented as microcontrollers with serial +interface (I<superscript>2</superscript>C) and can be found on older +TV cards, dedicated Teletext decoding cards and home-brew devices +connected to the PC parallel port.</para> + + <para>The Teletext API was designed by Martin Buck. It is defined in +the kernel header file <filename>linux/videotext.h</filename>, the +specification is available from <ulink url="http://home.pages.de/~videotext/"> +http://home.pages.de/~videotext/</ulink>. (Videotext is the name of +the German public television Teletext service.) Conventional character +device file names are <filename>/dev/vtx</filename> and +<filename>/dev/vttuner</filename>, with device number 83, 0 and 83, 16 +respectively. A similar interface exists for the Philips SAA5249 +Teletext decoder [specification?] with character device file names +<filename>/dev/tlkN</filename>, device number 102, N.</para> + + <para>Eventually the Teletext API was integrated into the V4L API +with character device file names <filename>/dev/vtx0</filename> to +<filename>/dev/vtx31</filename>, device major number 81, minor numbers +192 to 223. For reference the V4L Teletext API specification is +reproduced here in full: "Teletext interfaces talk the existing VTX +API." Teletext devices with major number 83 and 102 will be removed in +Linux 2.6.</para> + + <para>There are no plans to replace the Teletext API or to integrate +it into V4L2. Please write to the linux-media mailing list: &v4l-ml; +when the need arises.</para> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/driver.xml b/Documentation/DocBook/v4l/driver.xml new file mode 100644 index 0000000..1f7eea5 --- /dev/null +++ b/Documentation/DocBook/v4l/driver.xml @@ -0,0 +1,208 @@ + <title>V4L2 Driver Programming</title> + + <!-- This part defines the interface between the "videodev" + module and individual drivers. --> + + <para>to do</para> +<!-- + <para>V4L2 is a two-layer driver system. The top layer is the "videodev" +kernel module. When videodev initializes it registers as character device +with major number 81, and it registers a set of file operations. All V4L2 +drivers are really clients of videodev, which calls V4L2 drivers through +driver method functions. V4L2 drivers are also written as kernel modules. +After probing the hardware they register one or more devices with +videodev.</para> + + <section id="driver-modules"> + <title>Driver Modules</title> + + <para>V4L2 driver modules must have an initialization function which is +called after the module was loaded into kernel, an exit function whis is +called before the module is removed. When the driver is compiled into the +kernel these functions called at system boot and shutdown time.</para> + + <informalexample> + <programlisting> +#include <linux/module.h> + +/* Export information about this module. For details and other useful + macros see <filename>linux/module.h</filename>. */ +MODULE_DESCRIPTION("my - driver for my hardware"); +MODULE_AUTHOR("Your name here"); +MODULE_LICENSE("GPL"); + +static void +my_module_exit (void) +{ + /* Free all resources allocated by my_module_init(). */ +} + +static int +my_module_init (void) +{ + /* Bind the driver to the supported hardware, see + <link linkend="driver-pci"> and + <link linkend="driver-usb"> for examples. */ + + return 0; /* a negative value on error, 0 on success. */ +} + +/* Export module functions. */ +module_init (my_module_init); +module_exit (my_module_exit); +</programlisting> + </informalexample> + + <para>Users can add parameters when kernel modules are inserted:</para> + + <informalexample> + <programlisting> +include <linux/moduleparam.h> + +static int my_option = 123; +static int my_option_array[47]; + +/* Export the symbol, an int, with access permissions 0664. + See <filename>linux/moduleparam.h</filename> for other types. */ +module_param (my_option, int, 0644); +module_param_array (my_option_array, int, NULL, 0644); + +MODULE_PARM_DESC (my_option, "Does magic things, default 123"); +</programlisting> + </informalexample> + + <para>One parameter should be supported by all V4L2 drivers, the minor +number of the device it will register. Purpose is to predictably link V4L2 +drivers to device nodes if more than one video device is installed. Use the +name of the device node followed by a "_nr" suffix, for example "video_nr" +for <filename>/dev/video</filename>.</para> + + <informalexample> + <programlisting> +/* Minor number of the device, -1 to allocate the first unused. */ +static int video_nr = -1; + +module_param (video_nr, int, 0444); +</programlisting> + </informalexample> + </section> + + <section id="driver-pci"> + <title>PCI Devices</title> + + <para>PCI devices are initialized like this:</para> + + <informalexample> + <programlisting> +typedef struct { + /* State of one physical device. */ +} my_device; + +static int +my_resume (struct pci_dev * pci_dev) +{ + /* Restore the suspended device to working state. */ +} + +static int +my_suspend (struct pci_dev * pci_dev, + pm_message_t state) +{ + /* This function is called before the system goes to sleep. + Stop all DMAs and disable interrupts, then put the device + into a low power state. For details see the kernel + sources under <filename>Documentation/power</filename>. */ + + return 0; /* a negative value on error, 0 on success. */ +} + +static void __devexit +my_remove (struct pci_dev * pci_dev) +{ + my_device *my = pci_get_drvdata (pci_dev); + + /* Describe me. */ +} + +static int __devinit +my_probe (struct pci_dev * pci_dev, + const struct pci_device_id * pci_id) +{ + my_device *my; + + /* Describe me. */ + + /* You can allocate per-device data here and store a pointer + to it in the pci_dev structure. */ + my = ...; + pci_set_drvdata (pci_dev, my); + + return 0; /* a negative value on error, 0 on success. */ +} + +/* A list of supported PCI devices. */ +static struct pci_device_id +my_pci_device_ids [] = { + { PCI_VENDOR_ID_FOO, PCI_DEVICE_ID_BAR, + PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 }, + { 0 } /* end of list */ +}; + +/* Load our module if supported PCI devices are installed. */ +MODULE_DEVICE_TABLE (pci, my_pci_device_ids); + +static struct pci_driver +my_pci_driver = { + .name = "my", + .id_table = my_pci_device_ids, + + .probe = my_probe, + .remove = __devexit_p (my_remove), + + /* Power management functions. */ + .suspend = my_suspend, + .resume = my_resume, +}; + +static void +my_module_exit (void) +{ + pci_unregister_driver (&my_pci_driver); +} + +static int +my_module_init (void) +{ + return pci_register_driver (&my_pci_driver); +} +</programlisting> + </informalexample> + </section> + + <section id="driver-usb"> + <title>USB Devices</title> + <para>to do</para> + </section> + <section id="driver-registering"> + <title>Registering V4L2 Drivers</title> + + <para>After a V4L2 driver probed the hardware it registers one or more +devices with the videodev module.</para> + </section> + <section id="driver-file-ops"> + <title>File Operations</title> + <para>to do</para> + </section> + <section id="driver-internal-api"> + <title>Internal API</title> + <para>to do</para> + </section> +--> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/fdl-appendix.xml b/Documentation/DocBook/v4l/fdl-appendix.xml new file mode 100644 index 0000000..b6ce50d --- /dev/null +++ b/Documentation/DocBook/v4l/fdl-appendix.xml @@ -0,0 +1,671 @@ +<!-- + The GNU Free Documentation License 1.1 in DocBook + Markup by Eric Baudais <baudais@okstate.edu> + Maintained by the GNOME Documentation Project + http://developer.gnome.org/projects/gdp + Version: 1.0.1 + Last Modified: Nov 16, 2000 +--> + +<appendix id="fdl"> + <appendixinfo> + <releaseinfo> + Version 1.1, March 2000 + </releaseinfo> + <copyright> + <year>2000</year><holder>Free Software Foundation, Inc.</holder> + </copyright> + <legalnotice id="fdl-legalnotice"> + <para> + <address>Free Software Foundation, Inc. <street>59 Temple Place, + Suite 330</street>, <city>Boston</city>, <state>MA</state> + <postcode>02111-1307</postcode> <country>USA</country></address> + Everyone is permitted to copy and distribute verbatim copies of this + license document, but changing it is not allowed. + </para> + </legalnotice> + </appendixinfo> + <title>GNU Free Documentation License</title> + + <sect1 id="fdl-preamble"> + <title>0. PREAMBLE</title> + <para> + The purpose of this License is to make a manual, textbook, or + other written document <quote>free</quote> in the sense of + freedom: to assure everyone the effective freedom to copy and + redistribute it, with or without modifying it, either + commercially or noncommercially. Secondarily, this License + preserves for the author and publisher a way to get credit for + their work, while not being considered responsible for + modifications made by others. + </para> + + <para> + This License is a kind of <quote>copyleft</quote>, which means + that derivative works of the document must themselves be free in + the same sense. It complements the GNU General Public License, + which is a copyleft license designed for free software. + </para> + + <para> + We have designed this License in order to use it for manuals for + free software, because free software needs free documentation: a + free program should come with manuals providing the same + freedoms that the software does. But this License is not limited + to software manuals; it can be used for any textual work, + regardless of subject matter or whether it is published as a + printed book. We recommend this License principally for works + whose purpose is instruction or reference. + </para> + </sect1> + <sect1 id="fdl-section1"> + <title>1. APPLICABILITY AND DEFINITIONS</title> + <para id="fdl-document"> + This License applies to any manual or other work that contains a + notice placed by the copyright holder saying it can be + distributed under the terms of this License. The + <quote>Document</quote>, below, refers to any such manual or + work. Any member of the public is a licensee, and is addressed + as <quote>you</quote>. + </para> + + <para id="fdl-modified"> + A <quote>Modified Version</quote> of the Document means any work + containing the Document or a portion of it, either copied + verbatim, or with modifications and/or translated into another + language. + </para> + + <para id="fdl-secondary"> + A <quote>Secondary Section</quote> is a named appendix or a + front-matter section of the <link + linkend="fdl-document">Document</link> that deals exclusively + with the relationship of the publishers or authors of the + Document to the Document's overall subject (or to related + matters) and contains nothing that could fall directly within + that overall subject. (For example, if the Document is in part a + textbook of mathematics, a Secondary Section may not explain any + mathematics.) The relationship could be a matter of historical + connection with the subject or with related matters, or of + legal, commercial, philosophical, ethical or political position + regarding them. + </para> + + <para id="fdl-invariant"> + The <quote>Invariant Sections</quote> are certain <link + linkend="fdl-secondary"> Secondary Sections</link> whose titles + are designated, as being those of Invariant Sections, in the + notice that says that the <link + linkend="fdl-document">Document</link> is released under this + License. + </para> + + <para id="fdl-cover-texts"> + The <quote>Cover Texts</quote> are certain short passages of + text that are listed, as Front-Cover Texts or Back-Cover Texts, + in the notice that says that the <link + linkend="fdl-document">Document</link> is released under this + License. + </para> + + <para id="fdl-transparent"> + A <quote>Transparent</quote> copy of the <link + linkend="fdl-document"> Document</link> means a machine-readable + copy, represented in a format whose specification is available + to the general public, whose contents can be viewed and edited + directly and straightforwardly with generic text editors or (for + images composed of pixels) generic paint programs or (for + drawings) some widely available drawing editor, and that is + suitable for input to text formatters or for automatic + translation to a variety of formats suitable for input to text + formatters. A copy made in an otherwise Transparent file format + whose markup has been designed to thwart or discourage + subsequent modification by readers is not Transparent. A copy + that is not <quote>Transparent</quote> is called + <quote>Opaque</quote>. + </para> + + <para> + Examples of suitable formats for Transparent copies include + plain ASCII without markup, Texinfo input format, LaTeX input + format, SGML or XML using a publicly available DTD, and + standard-conforming simple HTML designed for human + modification. Opaque formats include PostScript, PDF, + proprietary formats that can be read and edited only by + proprietary word processors, SGML or XML for which the DTD + and/or processing tools are not generally available, and the + machine-generated HTML produced by some word processors for + output purposes only. + </para> + + <para id="fdl-title-page"> + The <quote>Title Page</quote> means, for a printed book, the + title page itself, plus such following pages as are needed to + hold, legibly, the material this License requires to appear in + the title page. For works in formats which do not have any title + page as such, <quote>Title Page</quote> means the text near the + most prominent appearance of the work's title, preceding the + beginning of the body of the text. + </para> + </sect1> + + <sect1 id="fdl-section2"> + <title>2. VERBATIM COPYING</title> + <para> + You may copy and distribute the <link + linkend="fdl-document">Document</link> in any medium, either + commercially or noncommercially, provided that this License, the + copyright notices, and the license notice saying this License + applies to the Document are reproduced in all copies, and that + you add no other conditions whatsoever to those of this + License. You may not use technical measures to obstruct or + control the reading or further copying of the copies you make or + distribute. However, you may accept compensation in exchange for + copies. If you distribute a large enough number of copies you + must also follow the conditions in <link + linkend="fdl-section3">section 3</link>. + </para> + + <para> + You may also lend copies, under the same conditions stated + above, and you may publicly display copies. + </para> + </sect1> + + <sect1 id="fdl-section3"> + <title>3. COPYING IN QUANTITY</title> + <para> + If you publish printed copies of the <link + linkend="fdl-document">Document</link> numbering more than 100, + and the Document's license notice requires <link + linkend="fdl-cover-texts">Cover Texts</link>, you must enclose + the copies in covers that carry, clearly and legibly, all these + Cover Texts: Front-Cover Texts on the front cover, and + Back-Cover Texts on the back cover. Both covers must also + clearly and legibly identify you as the publisher of these + copies. The front cover must present the full title with all + words of the title equally prominent and visible. You may add + other material on the covers in addition. Copying with changes + limited to the covers, as long as they preserve the title of the + <link linkend="fdl-document">Document</link> and satisfy these + conditions, can be treated as verbatim copying in other + respects. + </para> + + <para> + If the required texts for either cover are too voluminous to fit + legibly, you should put the first ones listed (as many as fit + reasonably) on the actual cover, and continue the rest onto + adjacent pages. + </para> + + <para> + If you publish or distribute <link + linkend="fdl-transparent">Opaque</link> copies of the <link + linkend="fdl-document">Document</link> numbering more than 100, + you must either include a machine-readable <link + linkend="fdl-transparent">Transparent</link> copy along with + each Opaque copy, or state in or with each Opaque copy a + publicly-accessible computer-network location containing a + complete Transparent copy of the Document, free of added + material, which the general network-using public has access to + download anonymously at no charge using public-standard network + protocols. If you use the latter option, you must take + reasonably prudent steps, when you begin distribution of Opaque + copies in quantity, to ensure that this Transparent copy will + remain thus accessible at the stated location until at least one + year after the last time you distribute an Opaque copy (directly + or through your agents or retailers) of that edition to the + public. + </para> + + <para> + It is requested, but not required, that you contact the authors + of the <link linkend="fdl-document">Document</link> well before + redistributing any large number of copies, to give them a chance + to provide you with an updated version of the Document. + </para> + </sect1> + + <sect1 id="fdl-section4"> + <title>4. MODIFICATIONS</title> + <para> + You may copy and distribute a <link + linkend="fdl-modified">Modified Version</link> of the <link + linkend="fdl-document">Document</link> under the conditions of + sections <link linkend="fdl-section2">2</link> and <link + linkend="fdl-section3">3</link> above, provided that you release + the Modified Version under precisely this License, with the + Modified Version filling the role of the Document, thus + licensing distribution and modification of the Modified Version + to whoever possesses a copy of it. In addition, you must do + these things in the Modified Version: + </para> + + <itemizedlist mark="opencircle"> + <listitem> + <formalpara> + <title>A</title> + <para> + Use in the <link linkend="fdl-title-page">Title + Page</link> (and on the covers, if any) a title distinct + from that of the <link + linkend="fdl-document">Document</link>, and from those of + previous versions (which should, if there were any, be + listed in the History section of the Document). You may + use the same title as a previous version if the original + publisher of that version gives permission. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>B</title> + <para> + List on the <link linkend="fdl-title-page">Title + Page</link>, as authors, one or more persons or entities + responsible for authorship of the modifications in the + <link linkend="fdl-modified">Modified Version</link>, + together with at least five of the principal authors of + the <link linkend="fdl-document">Document</link> (all of + its principal authors, if it has less than five). + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>C</title> + <para> + State on the <link linkend="fdl-title-page">Title + Page</link> the name of the publisher of the <link + linkend="fdl-modified">Modified Version</link>, as the + publisher. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>D</title> + <para> + Preserve all the copyright notices of the <link + linkend="fdl-document">Document</link>. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>E</title> + <para> + Add an appropriate copyright notice for your modifications + adjacent to the other copyright notices. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>F</title> + <para> + Include, immediately after the copyright notices, a + license notice giving the public permission to use the + <link linkend="fdl-modified">Modified Version</link> under + the terms of this License, in the form shown in the + Addendum below. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>G</title> + <para> + Preserve in that license notice the full lists of <link + linkend="fdl-invariant"> Invariant Sections</link> and + required <link linkend="fdl-cover-texts">Cover + Texts</link> given in the <link + linkend="fdl-document">Document's</link> license notice. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>H</title> + <para> + Include an unaltered copy of this License. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>I</title> + <para> + Preserve the section entitled <quote>History</quote>, and + its title, and add to it an item stating at least the + title, year, new authors, and publisher of the <link + linkend="fdl-modified">Modified Version </link>as given on + the <link linkend="fdl-title-page">Title Page</link>. If + there is no section entitled <quote>History</quote> in the + <link linkend="fdl-document">Document</link>, create one + stating the title, year, authors, and publisher of the + Document as given on its Title Page, then add an item + describing the Modified Version as stated in the previous + sentence. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>J</title> + <para> + Preserve the network location, if any, given in the <link + linkend="fdl-document">Document</link> for public access + to a <link linkend="fdl-transparent">Transparent</link> + copy of the Document, and likewise the network locations + given in the Document for previous versions it was based + on. These may be placed in the <quote>History</quote> + section. You may omit a network location for a work that + was published at least four years before the Document + itself, or if the original publisher of the version it + refers to gives permission. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>K</title> + <para> + In any section entitled <quote>Acknowledgements</quote> or + <quote>Dedications</quote>, preserve the section's title, + and preserve in the section all the substance and tone of + each of the contributor acknowledgements and/or + dedications given therein. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>L</title> + <para> + Preserve all the <link linkend="fdl-invariant">Invariant + Sections</link> of the <link + linkend="fdl-document">Document</link>, unaltered in their + text and in their titles. Section numbers or the + equivalent are not considered part of the section titles. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>M</title> + <para> + Delete any section entitled + <quote>Endorsements</quote>. Such a section may not be + included in the <link linkend="fdl-modified">Modified + Version</link>. + </para> + </formalpara> + </listitem> + + <listitem> + <formalpara> + <title>N</title> + <para> + Do not retitle any existing section as + <quote>Endorsements</quote> or to conflict in title with + any <link linkend="fdl-invariant">Invariant + Section</link>. + </para> + </formalpara> + </listitem> + </itemizedlist> + + <para> + If the <link linkend="fdl-modified">Modified Version</link> + includes new front-matter sections or appendices that qualify as + <link linkend="fdl-secondary">Secondary Sections</link> and + contain no material copied from the Document, you may at your + option designate some or all of these sections as invariant. To + do this, add their titles to the list of <link + linkend="fdl-invariant">Invariant Sections</link> in the + Modified Version's license notice. These titles must be + distinct from any other section titles. + </para> + + <para> + You may add a section entitled <quote>Endorsements</quote>, + provided it contains nothing but endorsements of your <link + linkend="fdl-modified">Modified Version</link> by various + parties--for example, statements of peer review or that the text + has been approved by an organization as the authoritative + definition of a standard. + </para> + + <para> + You may add a passage of up to five words as a <link + linkend="fdl-cover-texts">Front-Cover Text</link>, and a passage + of up to 25 words as a <link + linkend="fdl-cover-texts">Back-Cover Text</link>, to the end of + the list of <link linkend="fdl-cover-texts">Cover Texts</link> + in the <link linkend="fdl-modified">Modified Version</link>. + Only one passage of Front-Cover Text and one of Back-Cover Text + may be added by (or through arrangements made by) any one + entity. If the <link linkend="fdl-document">Document</link> + already includes a cover text for the same cover, previously + added by you or by arrangement made by the same entity you are + acting on behalf of, you may not add another; but you may + replace the old one, on explicit permission from the previous + publisher that added the old one. + </para> + + <para> + The author(s) and publisher(s) of the <link + linkend="fdl-document">Document</link> do not by this License + give permission to use their names for publicity for or to + assert or imply endorsement of any <link + linkend="fdl-modified">Modified Version </link>. + </para> + </sect1> + + <sect1 id="fdl-section5"> + <title>5. COMBINING DOCUMENTS</title> + <para> + You may combine the <link linkend="fdl-document">Document</link> + with other documents released under this License, under the + terms defined in <link linkend="fdl-section4">section 4</link> + above for modified versions, provided that you include in the + combination all of the <link linkend="fdl-invariant">Invariant + Sections</link> of all of the original documents, unmodified, + and list them all as Invariant Sections of your combined work in + its license notice. + </para> + + <para> + The combined work need only contain one copy of this License, + and multiple identical <link linkend="fdl-invariant">Invariant + Sections</link> may be replaced with a single copy. If there are + multiple Invariant Sections with the same name but different + contents, make the title of each such section unique by adding + at the end of it, in parentheses, the name of the original + author or publisher of that section if known, or else a unique + number. Make the same adjustment to the section titles in the + list of Invariant Sections in the license notice of the combined + work. + </para> + + <para> + In the combination, you must combine any sections entitled + <quote>History</quote> in the various original documents, + forming one section entitled <quote>History</quote>; likewise + combine any sections entitled <quote>Acknowledgements</quote>, + and any sections entitled <quote>Dedications</quote>. You must + delete all sections entitled <quote>Endorsements.</quote> + </para> + </sect1> + + <sect1 id="fdl-section6"> + <title>6. COLLECTIONS OF DOCUMENTS</title> + <para> + You may make a collection consisting of the <link + linkend="fdl-document">Document</link> and other documents + released under this License, and replace the individual copies + of this License in the various documents with a single copy that + is included in the collection, provided that you follow the + rules of this License for verbatim copying of each of the + documents in all other respects. + </para> + + <para> + You may extract a single document from such a collection, and + dispbibute it individually under this License, provided you + insert a copy of this License into the extracted document, and + follow this License in all other respects regarding verbatim + copying of that document. + </para> + </sect1> + + <sect1 id="fdl-section7"> + <title>7. AGGREGATION WITH INDEPENDENT WORKS</title> + <para> + A compilation of the <link + linkend="fdl-document">Document</link> or its derivatives with + other separate and independent documents or works, in or on a + volume of a storage or distribution medium, does not as a whole + count as a <link linkend="fdl-modified">Modified Version</link> + of the Document, provided no compilation copyright is claimed + for the compilation. Such a compilation is called an + <quote>aggregate</quote>, and this License does not apply to the + other self-contained works thus compiled with the Document , on + account of their being thus compiled, if they are not themselves + derivative works of the Document. If the <link + linkend="fdl-cover-texts">Cover Text</link> requirement of <link + linkend="fdl-section3">section 3</link> is applicable to these + copies of the Document, then if the Document is less than one + quarter of the entire aggregate, the Document's Cover Texts may + be placed on covers that surround only the Document within the + aggregate. Otherwise they must appear on covers around the whole + aggregate. + </para> + </sect1> + + <sect1 id="fdl-section8"> + <title>8. TRANSLATION</title> + <para> + Translation is considered a kind of modification, so you may + distribute translations of the <link + linkend="fdl-document">Document</link> under the terms of <link + linkend="fdl-section4">section 4</link>. Replacing <link + linkend="fdl-invariant"> Invariant Sections</link> with + translations requires special permission from their copyright + holders, but you may include translations of some or all + Invariant Sections in addition to the original versions of these + Invariant Sections. You may include a translation of this + License provided that you also include the original English + version of this License. In case of a disagreement between the + translation and the original English version of this License, + the original English version will prevail. + </para> + </sect1> + + <sect1 id="fdl-section9"> + <title>9. TERMINATION</title> + <para> + You may not copy, modify, sublicense, or distribute the <link + linkend="fdl-document">Document</link> except as expressly + provided for under this License. Any other attempt to copy, + modify, sublicense or distribute the Document is void, and will + automatically terminate your rights under this License. However, + parties who have received copies, or rights, from you under this + License will not have their licenses terminated so long as such + parties remain in full compliance. + </para> + </sect1> + + <sect1 id="fdl-section10"> + <title>10. FUTURE REVISIONS OF THIS LICENSE</title> + <para> + The <ulink type="http" + url="http://www.gnu.org/fsf/fsf.html">Free Software + Foundation</ulink> may publish new, revised versions of the GNU + Free Documentation License from time to time. Such new versions + will be similar in spirit to the present version, but may differ + in detail to address new problems or concerns. See <ulink + type="http" + url="http://www.gnu.org/copyleft">http://www.gnu.org/copyleft/</ulink>. + </para> + + <para> + Each version of the License is given a distinguishing version + number. If the <link linkend="fdl-document">Document</link> + specifies that a particular numbered version of this License + <quote>or any later version</quote> applies to it, you have the + option of following the terms and conditions either of that + specified version or of any later version that has been + published (not as a draft) by the Free Software Foundation. If + the Document does not specify a version number of this License, + you may choose any version ever published (not as a draft) by + the Free Software Foundation. + </para> + </sect1> + + <sect1 id="fdl-using"> + <title>Addendum</title> + <para> + To use this License in a document you have written, include a copy of + the License in the document and put the following copyright and + license notices just after the title page: + </para> + + <blockquote> + <para> + Copyright © YEAR YOUR NAME. + </para> + <para> + Permission is granted to copy, distribute and/or modify this + document under the terms of the GNU Free Documentation + License, Version 1.1 or any later version published by the + Free Software Foundation; with the <link + linkend="fdl-invariant">Invariant Sections</link> being LIST + THEIR TITLES, with the <link + linkend="fdl-cover-texts">Front-Cover Texts</link> being LIST, + and with the <link linkend="fdl-cover-texts">Back-Cover + Texts</link> being LIST. A copy of the license is included in + the section entitled <quote>GNU Free Documentation + License</quote>. + </para> + </blockquote> + + <para> + If you have no <link linkend="fdl-invariant">Invariant + Sections</link>, write <quote>with no Invariant Sections</quote> + instead of saying which ones are invariant. If you have no + <link linkend="fdl-cover-texts">Front-Cover Texts</link>, write + <quote>no Front-Cover Texts</quote> instead of + <quote>Front-Cover Texts being LIST</quote>; likewise for <link + linkend="fdl-cover-texts">Back-Cover Texts</link>. + </para> + + <para> + If your document contains nontrivial examples of program code, + we recommend releasing these examples in parallel under your + choice of free software license, such as the <ulink type="http" + url="http://www.gnu.org/copyleft/gpl.html"> GNU General Public + License</ulink>, to permit their use in free software. + </para> + </sect1> +</appendix> + + + + + + diff --git a/Documentation/DocBook/v4l/fieldseq_bt.gif b/Documentation/DocBook/v4l/fieldseq_bt.gif Binary files differnew file mode 100644 index 0000000..60e8569 --- /dev/null +++ b/Documentation/DocBook/v4l/fieldseq_bt.gif diff --git a/Documentation/DocBook/v4l/fieldseq_bt.pdf b/Documentation/DocBook/v4l/fieldseq_bt.pdf Binary files differnew file mode 100644 index 0000000..26598b2 --- /dev/null +++ b/Documentation/DocBook/v4l/fieldseq_bt.pdf diff --git a/Documentation/DocBook/v4l/fieldseq_tb.gif b/Documentation/DocBook/v4l/fieldseq_tb.gif Binary files differnew file mode 100644 index 0000000..718492f --- /dev/null +++ b/Documentation/DocBook/v4l/fieldseq_tb.gif diff --git a/Documentation/DocBook/v4l/fieldseq_tb.pdf b/Documentation/DocBook/v4l/fieldseq_tb.pdf Binary files differnew file mode 100644 index 0000000..4965b22 --- /dev/null +++ b/Documentation/DocBook/v4l/fieldseq_tb.pdf diff --git a/Documentation/DocBook/v4l/func-close.xml b/Documentation/DocBook/v4l/func-close.xml new file mode 100644 index 0000000..dfb41cb --- /dev/null +++ b/Documentation/DocBook/v4l/func-close.xml @@ -0,0 +1,70 @@ +<refentry id="func-close"> + <refmeta> + <refentrytitle>V4L2 close()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-close</refname> + <refpurpose>Close a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>close</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Closes the device. Any I/O in progress is terminated and +resources associated with the file descriptor are freed. However data +format parameters, current input or output, control values or other +properties remain unchanged.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>The function returns <returnvalue>0</returnvalue> on +success, <returnvalue>-1</returnvalue> on failure and the +<varname>errno</varname> is set appropriately. Possible error +codes:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid open file +descriptor.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/func-ioctl.xml b/Documentation/DocBook/v4l/func-ioctl.xml new file mode 100644 index 0000000..00f9690e --- /dev/null +++ b/Documentation/DocBook/v4l/func-ioctl.xml @@ -0,0 +1,146 @@ +<refentry id="func-ioctl"> + <refmeta> + <refentrytitle>V4L2 ioctl()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-ioctl</refname> + <refpurpose>Program a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <sys/ioctl.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>void *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>V4L2 ioctl request code as defined in the <link +linkend="videodev">videodev.h</link> header file, for example +VIDIOC_QUERYCAP.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a function parameter, usually a structure.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The <function>ioctl()</function> function is used to program +V4L2 devices. The argument <parameter>fd</parameter> must be an open +file descriptor. An ioctl <parameter>request</parameter> has encoded +in it whether the argument is an input, output or read/write +parameter, and the size of the argument <parameter>argp</parameter> in +bytes. Macros and defines specifying V4L2 ioctl requests are located +in the <link linkend="videodev">videodev.h</link> header file. +Applications should use their own copy, not include the version in the +kernel sources on the system they compile on. All V4L2 ioctl requests, +their respective function and parameters are specified in <xref + linkend="user-func" />.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success the <function>ioctl()</function> function returns +<returnvalue>0</returnvalue> and does not reset the +<varname>errno</varname> variable. On failure +<returnvalue>-1</returnvalue> is returned, when the ioctl takes an +output or read/write parameter it remains unmodified, and the +<varname>errno</varname> variable is set appropriately. See below for +possible error codes. Generic errors like <errorcode>EBADF</errorcode> +or <errorcode>EFAULT</errorcode> are not listed in the sections +discussing individual ioctl requests.</para> + <para>Note ioctls may return undefined error codes. Since errors +may have side effects such as a driver reset applications should +abort on unexpected errors.</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid open file +descriptor.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The property cannot be changed right now. Typically +this error code is returned when I/O is in progress or the driver +supports multiple opens and another process locked the property.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>argp</parameter> references an inaccessible +memory area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOTTY</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not associated with a +character special device.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>request</parameter> or the data pointed +to by <parameter>argp</parameter> is not valid. This is a very common +error code, see the individual ioctl requests listed in <xref + linkend="user-func" /> for actual causes.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Not enough physical or virtual memory was available to +complete the request.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ERANGE</errorcode></term> + <listitem> + <para>The application attempted to set a control with the +&VIDIOC-S-CTRL; ioctl to a value which is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/func-mmap.xml b/Documentation/DocBook/v4l/func-mmap.xml new file mode 100644 index 0000000..2e2fc39 --- /dev/null +++ b/Documentation/DocBook/v4l/func-mmap.xml @@ -0,0 +1,185 @@ +<refentry id="func-mmap"> + <refmeta> + <refentrytitle>V4L2 mmap()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-mmap</refname> + <refpurpose>Map device memory into application address space</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo> +#include <unistd.h> +#include <sys/mman.h></funcsynopsisinfo> + <funcprototype> + <funcdef>void *<function>mmap</function></funcdef> + <paramdef>void *<parameter>start</parameter></paramdef> + <paramdef>size_t <parameter>length</parameter></paramdef> + <paramdef>int <parameter>prot</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>off_t <parameter>offset</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + <variablelist> + <varlistentry> + <term><parameter>start</parameter></term> + <listitem> + <para>Map the buffer to this address in the +application's address space. When the <constant>MAP_FIXED</constant> +flag is specified, <parameter>start</parameter> must be a multiple of the +pagesize and mmap will fail when the specified address +cannot be used. Use of this option is discouraged; applications should +just specify a <constant>NULL</constant> pointer here.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>length</parameter></term> + <listitem> + <para>Length of the memory area to map. This must be the +same value as returned by the driver in the &v4l2-buffer; +<structfield>length</structfield> field.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>prot</parameter></term> + <listitem> + <para>The <parameter>prot</parameter> argument describes the +desired memory protection. Regardless of the device type and the +direction of data exchange it should be set to +<constant>PROT_READ</constant> | <constant>PROT_WRITE</constant>, +permitting read and write access to image buffers. Drivers should +support at least this combination of flags. Note the Linux +<filename>video-buf</filename> kernel module, which is used by the +bttv, saa7134, saa7146, cx88 and vivi driver supports only +<constant>PROT_READ</constant> | <constant>PROT_WRITE</constant>. When +the driver does not support the desired protection the +<function>mmap()</function> function fails.</para> + <para>Note device memory accesses (⪚ the memory on a +graphics card with video capturing hardware) may incur a performance +penalty compared to main memory accesses, or reads may be +significantly slower than writes or vice versa. Other I/O methods may +be more efficient in this case.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>flags</parameter></term> + <listitem> + <para>The <parameter>flags</parameter> parameter +specifies the type of the mapped object, mapping options and whether +modifications made to the mapped copy of the page are private to the +process or are to be shared with other references.</para> + <para><constant>MAP_FIXED</constant> requests that the +driver selects no other address than the one specified. If the +specified address cannot be used, <function>mmap()</function> will fail. If +<constant>MAP_FIXED</constant> is specified, +<parameter>start</parameter> must be a multiple of the pagesize. Use +of this option is discouraged.</para> + <para>One of the <constant>MAP_SHARED</constant> or +<constant>MAP_PRIVATE</constant> flags must be set. +<constant>MAP_SHARED</constant> allows applications to share the +mapped memory with other (⪚ child-) processes. Note the Linux +<filename>video-buf</filename> module which is used by the bttv, +saa7134, saa7146, cx88 and vivi driver supports only +<constant>MAP_SHARED</constant>. <constant>MAP_PRIVATE</constant> +requests copy-on-write semantics. V4L2 applications should not set the +<constant>MAP_PRIVATE</constant>, <constant>MAP_DENYWRITE</constant>, +<constant>MAP_EXECUTABLE</constant> or <constant>MAP_ANON</constant> +flag.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>offset</parameter></term> + <listitem> + <para>Offset of the buffer in device memory. This must be the +same value as returned by the driver in the &v4l2-buffer; +<structfield>m</structfield> union <structfield>offset</structfield> field.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The <function>mmap()</function> function asks to map +<parameter>length</parameter> bytes starting at +<parameter>offset</parameter> in the memory of the device specified by +<parameter>fd</parameter> into the application address space, +preferably at address <parameter>start</parameter>. This latter +address is a hint only, and is usually specified as 0.</para> + + <para>Suitable length and offset parameters are queried with the +&VIDIOC-QUERYBUF; ioctl. Buffers must be allocated with the +&VIDIOC-REQBUFS; ioctl before they can be queried.</para> + + <para>To unmap buffers the &func-munmap; function is used.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success <function>mmap()</function> returns a pointer to +the mapped buffer. On error <constant>MAP_FAILED</constant> (-1) is +returned, and the <varname>errno</varname> variable is set +appropriately. Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid file +descriptor.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is +not open for reading and writing.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>start</parameter> or +<parameter>length</parameter> or <parameter>offset</parameter> are not +suitable. (E. g. they are too large, or not aligned on a +<constant>PAGESIZE</constant> boundary.)</para> + <para>The <parameter>flags</parameter> or +<parameter>prot</parameter> value is not supported.</para> + <para>No buffers have been allocated with the +&VIDIOC-REQBUFS; ioctl.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Not enough physical or virtual memory was available to +complete the request.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/func-munmap.xml b/Documentation/DocBook/v4l/func-munmap.xml new file mode 100644 index 0000000..502ed49 --- /dev/null +++ b/Documentation/DocBook/v4l/func-munmap.xml @@ -0,0 +1,83 @@ +<refentry id="func-munmap"> + <refmeta> + <refentrytitle>V4L2 munmap()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-munmap</refname> + <refpurpose>Unmap device memory</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo> +#include <unistd.h> +#include <sys/mman.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>munmap</function></funcdef> + <paramdef>void *<parameter>start</parameter></paramdef> + <paramdef>size_t <parameter>length</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + <refsect1> + <title>Arguments</title> + <variablelist> + <varlistentry> + <term><parameter>start</parameter></term> + <listitem> + <para>Address of the mapped buffer as returned by the +&func-mmap; function.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>length</parameter></term> + <listitem> + <para>Length of the mapped buffer. This must be the same +value as given to <function>mmap()</function> and returned by the +driver in the &v4l2-buffer; <structfield>length</structfield> +field.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Unmaps a previously with the &func-mmap; function mapped +buffer and frees it, if possible. <!-- ? This function (not freeing) +has no impact on I/O in progress, specifically it does not imply +&VIDIOC-STREAMOFF; to terminate I/O. Unmapped buffers can still be +enqueued, dequeued or queried, they are just not accessible by the +application.--></para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success <function>munmap()</function> returns 0, on +failure -1 and the <varname>errno</varname> variable is set +appropriately:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>start</parameter> or +<parameter>length</parameter> is incorrect, or no buffers have been +mapped yet.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/func-open.xml b/Documentation/DocBook/v4l/func-open.xml new file mode 100644 index 0000000..7595d07 --- /dev/null +++ b/Documentation/DocBook/v4l/func-open.xml @@ -0,0 +1,121 @@ +<refentry id="func-open"> + <refmeta> + <refentrytitle>V4L2 open()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-open</refname> + <refpurpose>Open a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <fcntl.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>open</function></funcdef> + <paramdef>const char *<parameter>device_name</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>device_name</parameter></term> + <listitem> + <para>Device to be opened.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>flags</parameter></term> + <listitem> + <para>Open flags. Access mode must be +<constant>O_RDWR</constant>. This is just a technicality, input devices +still support only reading and output devices only writing.</para> + <para>When the <constant>O_NONBLOCK</constant> flag is +given, the read() function and the &VIDIOC-DQBUF; ioctl will return +the &EAGAIN; when no data is available or no buffer is in the driver +outgoing queue, otherwise these functions block until data becomes +available. All V4L2 drivers exchanging data with applications must +support the <constant>O_NONBLOCK</constant> flag.</para> + <para>Other flags have no effect.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + <refsect1> + <title>Description</title> + + <para>To open a V4L2 device applications call +<function>open()</function> with the desired device name. This +function has no side effects; all data format parameters, current +input or output, control values or other properties remain unchanged. +At the first <function>open()</function> call after loading the driver +they will be reset to default values, drivers are never in an +undefined state.</para> + </refsect1> + <refsect1> + <title>Return Value</title> + + <para>On success <function>open</function> returns the new file +descriptor. On error -1 is returned, and the <varname>errno</varname> +variable is set appropriately. Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para>The caller has no permission to access the +device.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple opens and the +device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENXIO</errorcode></term> + <listitem> + <para>No device corresponding to this device special file +exists.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Not enough kernel memory was available to complete the +request.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EMFILE</errorcode></term> + <listitem> + <para>The process already has the maximum number of +files open.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENFILE</errorcode></term> + <listitem> + <para>The limit on the total number of files open on the +system has been reached.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/func-poll.xml b/Documentation/DocBook/v4l/func-poll.xml new file mode 100644 index 0000000..ec3c718 --- /dev/null +++ b/Documentation/DocBook/v4l/func-poll.xml @@ -0,0 +1,127 @@ +<refentry id="func-poll"> + <refmeta> + <refentrytitle>V4L2 poll()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-poll</refname> + <refpurpose>Wait for some event on a file descriptor</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <sys/poll.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>poll</function></funcdef> + <paramdef>struct pollfd *<parameter>ufds</parameter></paramdef> + <paramdef>unsigned int <parameter>nfds</parameter></paramdef> + <paramdef>int <parameter>timeout</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>With the <function>poll()</function> function applications +can suspend execution until the driver has captured data or is ready +to accept data for output.</para> + + <para>When streaming I/O has been negotiated this function waits +until a buffer has been filled or displayed and can be dequeued with +the &VIDIOC-DQBUF; ioctl. When buffers are already in the outgoing +queue of the driver the function returns immediately.</para> + + <para>On success <function>poll()</function> returns the number of +file descriptors that have been selected (that is, file descriptors +for which the <structfield>revents</structfield> field of the +respective <structname>pollfd</structname> structure is non-zero). +Capture devices set the <constant>POLLIN</constant> and +<constant>POLLRDNORM</constant> flags in the +<structfield>revents</structfield> field, output devices the +<constant>POLLOUT</constant> and <constant>POLLWRNORM</constant> +flags. When the function timed out it returns a value of zero, on +failure it returns <returnvalue>-1</returnvalue> and the +<varname>errno</varname> variable is set appropriately. When the +application did not call &VIDIOC-QBUF; or &VIDIOC-STREAMON; yet the +<function>poll()</function> function succeeds, but sets the +<constant>POLLERR</constant> flag in the +<structfield>revents</structfield> field.</para> + + <para>When use of the <function>read()</function> function has +been negotiated and the driver does not capture yet, the +<function>poll</function> function starts capturing. When that fails +it returns a <constant>POLLERR</constant> as above. Otherwise it waits +until data has been captured and can be read. When the driver captures +continuously (as opposed to, for example, still images) the function +may return immediately.</para> + + <para>When use of the <function>write()</function> function has +been negotiated the <function>poll</function> function just waits +until the driver is ready for a non-blocking +<function>write()</function> call.</para> + + <para>All drivers implementing the <function>read()</function> or +<function>write()</function> function or streaming I/O must also +support the <function>poll()</function> function.</para> + + <para>For more details see the +<function>poll()</function> manual page.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, <function>poll()</function> returns the number +structures which have non-zero <structfield>revents</structfield> +fields, or zero if the call timed out. On error +<returnvalue>-1</returnvalue> is returned, and the +<varname>errno</varname> variable is set appropriately:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para>One or more of the <parameter>ufds</parameter> members +specify an invalid file descriptor.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple read or write +streams and the device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>ufds</parameter> references an inaccessible +memory area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINTR</errorcode></term> + <listitem> + <para>The call was interrupted by a signal.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>nfds</parameter> argument is greater +than <constant>OPEN_MAX</constant>.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/func-read.xml b/Documentation/DocBook/v4l/func-read.xml new file mode 100644 index 0000000..a5089bf --- /dev/null +++ b/Documentation/DocBook/v4l/func-read.xml @@ -0,0 +1,189 @@ +<refentry id="func-read"> + <refmeta> + <refentrytitle>V4L2 read()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-read</refname> + <refpurpose>Read from a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>ssize_t <function>read</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>void *<parameter>buf</parameter></paramdef> + <paramdef>size_t <parameter>count</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>buf</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>count</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para><function>read()</function> attempts to read up to +<parameter>count</parameter> bytes from file descriptor +<parameter>fd</parameter> into the buffer starting at +<parameter>buf</parameter>. The layout of the data in the buffer is +discussed in the respective device interface section, see ##. If <parameter>count</parameter> is zero, +<function>read()</function> returns zero and has no other results. If +<parameter>count</parameter> is greater than +<constant>SSIZE_MAX</constant>, the result is unspecified. Regardless +of the <parameter>count</parameter> value each +<function>read()</function> call will provide at most one frame (two +fields) worth of data.</para> + + <para>By default <function>read()</function> blocks until data +becomes available. When the <constant>O_NONBLOCK</constant> flag was +given to the &func-open; function it +returns immediately with an &EAGAIN; when no data is available. The +&func-select; or &func-poll; functions +can always be used to suspend execution until data becomes available. All +drivers supporting the <function>read()</function> function must also +support <function>select()</function> and +<function>poll()</function>.</para> + + <para>Drivers can implement read functionality in different +ways, using a single or multiple buffers and discarding the oldest or +newest frames once the internal buffers are filled.</para> + + <para><function>read()</function> never returns a "snapshot" of a +buffer being filled. Using a single buffer the driver will stop +capturing when the application starts reading the buffer until the +read is finished. Thus only the period of the vertical blanking +interval is available for reading, or the capture rate must fall below +the nominal frame rate of the video standard.</para> + +<para>The behavior of +<function>read()</function> when called during the active picture +period or the vertical blanking separating the top and bottom field +depends on the discarding policy. A driver discarding the oldest +frames keeps capturing into an internal buffer, continuously +overwriting the previously, not read frame, and returns the frame +being received at the time of the <function>read()</function> call as +soon as it is complete.</para> + + <para>A driver discarding the newest frames stops capturing until +the next <function>read()</function> call. The frame being received at +<function>read()</function> time is discarded, returning the following +frame instead. Again this implies a reduction of the capture rate to +one half or less of the nominal frame rate. An example of this model +is the video read mode of the bttv driver, initiating a DMA to user +memory when <function>read()</function> is called and returning when +the DMA finished.</para> + + <para>In the multiple buffer model drivers maintain a ring of +internal buffers, automatically advancing to the next free buffer. +This allows continuous capturing when the application can empty the +buffers fast enough. Again, the behavior when the driver runs out of +free buffers depends on the discarding policy.</para> + + <para>Applications can get and set the number of buffers used +internally by the driver with the &VIDIOC-G-PARM; and &VIDIOC-S-PARM; +ioctls. They are optional, however. The discarding policy is not +reported and cannot be changed. For minimum requirements see <xref + linkend="devices" />.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, the number of bytes read is returned. It is not +an error if this number is smaller than the number of bytes requested, +or the amount of data required for one frame. This may happen for +example because <function>read()</function> was interrupted by a +signal. On error, -1 is returned, and the <varname>errno</varname> +variable is set appropriately. In this case the next read will start +at the beginning of a new frame. Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EAGAIN</errorcode></term> + <listitem> + <para>Non-blocking I/O has been selected using +O_NONBLOCK and no data was immediately available for reading.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid file +descriptor or is not open for reading, or the process already has the +maximum number of files open.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple read streams and the +device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>buf</parameter> references an inaccessible +memory area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINTR</errorcode></term> + <listitem> + <para>The call was interrupted by a signal before any +data was read.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EIO</errorcode></term> + <listitem> + <para>I/O error. This indicates some hardware problem or a +failure to communicate with a remote device (USB camera etc.).</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <function>read()</function> function is not +supported by this driver, not on this device, or generally not on this +type of device.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/func-select.xml b/Documentation/DocBook/v4l/func-select.xml new file mode 100644 index 0000000..b671362 --- /dev/null +++ b/Documentation/DocBook/v4l/func-select.xml @@ -0,0 +1,138 @@ +<refentry id="func-select"> + <refmeta> + <refentrytitle>V4L2 select()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-select</refname> + <refpurpose>Synchronous I/O multiplexing</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo> +#include <sys/time.h> +#include <sys/types.h> +#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>select</function></funcdef> + <paramdef>int <parameter>nfds</parameter></paramdef> + <paramdef>fd_set *<parameter>readfds</parameter></paramdef> + <paramdef>fd_set *<parameter>writefds</parameter></paramdef> + <paramdef>fd_set *<parameter>exceptfds</parameter></paramdef> + <paramdef>struct timeval *<parameter>timeout</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>With the <function>select()</function> function applications +can suspend execution until the driver has captured data or is ready +to accept data for output.</para> + + <para>When streaming I/O has been negotiated this function waits +until a buffer has been filled or displayed and can be dequeued with +the &VIDIOC-DQBUF; ioctl. When buffers are already in the outgoing +queue of the driver the function returns immediately.</para> + + <para>On success <function>select()</function> returns the total +number of bits set in the <structname>fd_set</structname>s. When the +function timed out it returns a value of zero. On failure it returns +<returnvalue>-1</returnvalue> and the <varname>errno</varname> +variable is set appropriately. When the application did not call +&VIDIOC-QBUF; or &VIDIOC-STREAMON; yet the +<function>select()</function> function succeeds, setting the bit of +the file descriptor in <parameter>readfds</parameter> or +<parameter>writefds</parameter>, but subsequent &VIDIOC-DQBUF; calls +will fail.<footnote><para>The Linux kernel implements +<function>select()</function> like the &func-poll; function, but +<function>select()</function> cannot return a +<constant>POLLERR</constant>.</para> + </footnote></para> + + <para>When use of the <function>read()</function> function has +been negotiated and the driver does not capture yet, the +<function>select()</function> function starts capturing. When that +fails, <function>select()</function> returns successful and a +subsequent <function>read()</function> call, which also attempts to +start capturing, will return an appropriate error code. When the +driver captures continuously (as opposed to, for example, still +images) and data is already available the +<function>select()</function> function returns immediately.</para> + + <para>When use of the <function>write()</function> function has +been negotiated the <function>select()</function> function just waits +until the driver is ready for a non-blocking +<function>write()</function> call.</para> + + <para>All drivers implementing the <function>read()</function> or +<function>write()</function> function or streaming I/O must also +support the <function>select()</function> function.</para> + + <para>For more details see the <function>select()</function> +manual page.</para> + + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, <function>select()</function> returns the number +of descriptors contained in the three returned descriptor sets, which +will be zero if the timeout expired. On error +<returnvalue>-1</returnvalue> is returned, and the +<varname>errno</varname> variable is set appropriately; the sets and +<parameter>timeout</parameter> are undefined. Possible error codes +are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para>One or more of the file descriptor sets specified a +file descriptor that is not open.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple read or write +streams and the device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para>The <parameter>readfds</parameter>, +<parameter>writefds</parameter>, <parameter>exceptfds</parameter> or +<parameter>timeout</parameter> pointer references an inaccessible memory +area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINTR</errorcode></term> + <listitem> + <para>The call was interrupted by a signal.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>nfds</parameter> argument is less than +zero or greater than <constant>FD_SETSIZE</constant>.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/func-write.xml b/Documentation/DocBook/v4l/func-write.xml new file mode 100644 index 0000000..2c09c09 --- /dev/null +++ b/Documentation/DocBook/v4l/func-write.xml @@ -0,0 +1,136 @@ +<refentry id="func-write"> + <refmeta> + <refentrytitle>V4L2 write()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>v4l2-write</refname> + <refpurpose>Write to a V4L2 device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <unistd.h></funcsynopsisinfo> + <funcprototype> + <funcdef>ssize_t <function>write</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>void *<parameter>buf</parameter></paramdef> + <paramdef>size_t <parameter>count</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>buf</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>count</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para><function>write()</function> writes up to +<parameter>count</parameter> bytes to the device referenced by the +file descriptor <parameter>fd</parameter> from the buffer starting at +<parameter>buf</parameter>. When the hardware outputs are not active +yet, this function enables them. When <parameter>count</parameter> is +zero, <function>write()</function> returns +<returnvalue>0</returnvalue> without any other effect.</para> + + <para>When the application does not provide more data in time, the +previous video frame, raw VBI image, sliced VPS or WSS data is +displayed again. Sliced Teletext or Closed Caption data is not +repeated, the driver inserts a blank line instead.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, the number of bytes written are returned. Zero +indicates nothing was written. On error, <returnvalue>-1</returnvalue> +is returned, and the <varname>errno</varname> variable is set +appropriately. In this case the next write will start at the beginning +of a new frame. Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EAGAIN</errorcode></term> + <listitem> + <para>Non-blocking I/O has been selected using the <link +linkend="func-open"><constant>O_NONBLOCK</constant></link> flag and no +buffer space was available to write the data immediately.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid file +descriptor or is not open for writing.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver does not support multiple write streams and the +device is already in use.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>buf</parameter> references an inaccessible +memory area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINTR</errorcode></term> + <listitem> + <para>The call was interrupted by a signal before any +data was written.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EIO</errorcode></term> + <listitem> + <para>I/O error. This indicates some hardware problem.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <function>write()</function> function is not +supported by this driver, not on this device, or generally not on this +type of device.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/io.xml b/Documentation/DocBook/v4l/io.xml new file mode 100644 index 0000000..f92f243 --- /dev/null +++ b/Documentation/DocBook/v4l/io.xml @@ -0,0 +1,1073 @@ + <title>Input/Output</title> + + <para>The V4L2 API defines several different methods to read from or +write to a device. All drivers exchanging data with applications must +support at least one of them.</para> + + <para>The classic I/O method using the <function>read()</function> +and <function>write()</function> function is automatically selected +after opening a V4L2 device. When the driver does not support this +method attempts to read or write will fail at any time.</para> + + <para>Other methods must be negotiated. To select the streaming I/O +method with memory mapped or user buffers applications call the +&VIDIOC-REQBUFS; ioctl. The asynchronous I/O method is not defined +yet.</para> + + <para>Video overlay can be considered another I/O method, although +the application does not directly receive the image data. It is +selected by initiating video overlay with the &VIDIOC-S-FMT; ioctl. +For more information see <xref linkend="overlay" />.</para> + + <para>Generally exactly one I/O method, including overlay, is +associated with each file descriptor. The only exceptions are +applications not exchanging data with a driver ("panel applications", +see <xref linkend="open" />) and drivers permitting simultaneous video capturing +and overlay using the same file descriptor, for compatibility with V4L +and earlier versions of V4L2.</para> + + <para><constant>VIDIOC_S_FMT</constant> and +<constant>VIDIOC_REQBUFS</constant> would permit this to some degree, +but for simplicity drivers need not support switching the I/O method +(after first switching away from read/write) other than by closing +and reopening the device.</para> + + <para>The following sections describe the various I/O methods in +more detail.</para> + + <section id="rw"> + <title>Read/Write</title> + + <para>Input and output devices support the +<function>read()</function> and <function>write()</function> function, +respectively, when the <constant>V4L2_CAP_READWRITE</constant> flag in +the <structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set.</para> + + <para>Drivers may need the CPU to copy the data, but they may also +support DMA to or from user memory, so this I/O method is not +necessarily less efficient than other methods merely exchanging buffer +pointers. It is considered inferior though because no meta-information +like frame counters or timestamps are passed. This information is +necessary to recognize frame dropping and to synchronize with other +data streams. However this is also the simplest I/O method, requiring +little or no setup to exchange data. It permits command line stunts +like this (the <application>vidctrl</application> tool is +fictitious):</para> + + <informalexample> + <screen> +> vidctrl /dev/video --input=0 --format=YUYV --size=352x288 +> dd if=/dev/video of=myimage.422 bs=202752 count=1 +</screen> + </informalexample> + + <para>To read from the device applications use the +&func-read; function, to write the &func-write; function. +Drivers must implement one I/O method if they +exchange data with applications, but it need not be this.<footnote> + <para>It would be desirable if applications could depend on +drivers supporting all I/O interfaces, but as much as the complex +memory mapping I/O can be inadequate for some devices we have no +reason to require this interface, which is most useful for simple +applications capturing still images.</para> + </footnote> When reading or writing is supported, the driver +must also support the &func-select; and &func-poll; +function.<footnote> + <para>At the driver level <function>select()</function> and +<function>poll()</function> are the same, and +<function>select()</function> is too important to be optional.</para> + </footnote></para> + </section> + + <section id="mmap"> + <title>Streaming I/O (Memory Mapping)</title> + + <para>Input and output devices support this I/O method when the +<constant>V4L2_CAP_STREAMING</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set. There are two +streaming methods, to determine if the memory mapping flavor is +supported applications must call the &VIDIOC-REQBUFS; ioctl.</para> + + <para>Streaming is an I/O method where only pointers to buffers +are exchanged between application and driver, the data itself is not +copied. Memory mapping is primarily intended to map buffers in device +memory into the application's address space. Device memory can be for +example the video memory on a graphics card with a video capture +add-on. However, being the most efficient I/O method available for a +long time, many other drivers support streaming as well, allocating +buffers in DMA-able main memory.</para> + + <para>A driver can support many sets of buffers. Each set is +identified by a unique buffer type value. The sets are independent and +each set can hold a different type of data. To access different sets +at the same time different file descriptors must be used.<footnote> + <para>One could use one file descriptor and set the buffer +type field accordingly when calling &VIDIOC-QBUF; etc., but it makes +the <function>select()</function> function ambiguous. We also like the +clean approach of one file descriptor per logical stream. Video +overlay for example is also a logical stream, although the CPU is not +needed for continuous operation.</para> + </footnote></para> + + <para>To allocate device buffers applications call the +&VIDIOC-REQBUFS; ioctl with the desired number of buffers and buffer +type, for example <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>. +This ioctl can also be used to change the number of buffers or to free +the allocated memory, provided none of the buffers are still +mapped.</para> + + <para>Before applications can access the buffers they must map +them into their address space with the &func-mmap; function. The +location of the buffers in device memory can be determined with the +&VIDIOC-QUERYBUF; ioctl. The <structfield>m.offset</structfield> and +<structfield>length</structfield> returned in a &v4l2-buffer; are +passed as sixth and second parameter to the +<function>mmap()</function> function. The offset and length values +must not be modified. Remember the buffers are allocated in physical +memory, as opposed to virtual memory which can be swapped out to disk. +Applications should free the buffers as soon as possible with the +&func-munmap; function.</para> + + <example> + <title>Mapping buffers</title> + + <programlisting> +&v4l2-requestbuffers; reqbuf; +struct { + void *start; + size_t length; +} *buffers; +unsigned int i; + +memset (&reqbuf, 0, sizeof (reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +reqbuf.memory = V4L2_MEMORY_MMAP; +reqbuf.count = 20; + +if (-1 == ioctl (fd, &VIDIOC-REQBUFS;, &reqbuf)) { + if (errno == EINVAL) + printf ("Video capturing or mmap-streaming is not supported\n"); + else + perror ("VIDIOC_REQBUFS"); + + exit (EXIT_FAILURE); +} + +/* We want at least five buffers. */ + +if (reqbuf.count < 5) { + /* You may need to free the buffers here. */ + printf ("Not enough buffer memory\n"); + exit (EXIT_FAILURE); +} + +buffers = calloc (reqbuf.count, sizeof (*buffers)); +assert (buffers != NULL); + +for (i = 0; i < reqbuf.count; i++) { + &v4l2-buffer; buffer; + + memset (&buffer, 0, sizeof (buffer)); + buffer.type = reqbuf.type; + buffer.memory = V4L2_MEMORY_MMAP; + buffer.index = i; + + if (-1 == ioctl (fd, &VIDIOC-QUERYBUF;, &buffer)) { + perror ("VIDIOC_QUERYBUF"); + exit (EXIT_FAILURE); + } + + buffers[i].length = buffer.length; /* remember for munmap() */ + + buffers[i].start = mmap (NULL, buffer.length, + PROT_READ | PROT_WRITE, /* recommended */ + MAP_SHARED, /* recommended */ + fd, buffer.m.offset); + + if (MAP_FAILED == buffers[i].start) { + /* If you do not exit here you should unmap() and free() + the buffers mapped so far. */ + perror ("mmap"); + exit (EXIT_FAILURE); + } +} + +/* Cleanup. */ + +for (i = 0; i < reqbuf.count; i++) + munmap (buffers[i].start, buffers[i].length); + </programlisting> + </example> + + <para>Conceptually streaming drivers maintain two buffer queues, an incoming +and an outgoing queue. They separate the synchronous capture or output +operation locked to a video clock from the application which is +subject to random disk or network delays and preemption by +other processes, thereby reducing the probability of data loss. +The queues are organized as FIFOs, buffers will be +output in the order enqueued in the incoming FIFO, and were +captured in the order dequeued from the outgoing FIFO.</para> + + <para>The driver may require a minimum number of buffers enqueued +at all times to function, apart of this no limit exists on the number +of buffers applications can enqueue in advance, or dequeue and +process. They can also enqueue in a different order than buffers have +been dequeued, and the driver can <emphasis>fill</emphasis> enqueued +<emphasis>empty</emphasis> buffers in any order. <footnote> + <para>Random enqueue order permits applications processing +images out of order (such as video codecs) to return buffers earlier, +reducing the probability of data loss. Random fill order allows +drivers to reuse buffers on a LIFO-basis, taking advantage of caches +holding scatter-gather lists and the like.</para> + </footnote> The index number of a buffer (&v4l2-buffer; +<structfield>index</structfield>) plays no role here, it only +identifies the buffer.</para> + + <para>Initially all mapped buffers are in dequeued state, +inaccessible by the driver. For capturing applications it is customary +to first enqueue all mapped buffers, then to start capturing and enter +the read loop. Here the application waits until a filled buffer can be +dequeued, and re-enqueues the buffer when the data is no longer +needed. Output applications fill and enqueue buffers, when enough +buffers are stacked up the output is started with +<constant>VIDIOC_STREAMON</constant>. In the write loop, when +the application runs out of free buffers, it must wait until an empty +buffer can be dequeued and reused.</para> + + <para>To enqueue and dequeue a buffer applications use the +&VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl. The status of a buffer being +mapped, enqueued, full or empty can be determined at any time using the +&VIDIOC-QUERYBUF; ioctl. Two methods exist to suspend execution of the +application until one or more buffers can be dequeued. By default +<constant>VIDIOC_DQBUF</constant> blocks when no buffer is in the +outgoing queue. When the <constant>O_NONBLOCK</constant> flag was +given to the &func-open; function, <constant>VIDIOC_DQBUF</constant> +returns immediately with an &EAGAIN; when no buffer is available. The +&func-select; or &func-poll; function are always available.</para> + + <para>To start and stop capturing or output applications call the +&VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctl. Note +<constant>VIDIOC_STREAMOFF</constant> removes all buffers from both +queues as a side effect. Since there is no notion of doing anything +"now" on a multitasking system, if an application needs to synchronize +with another event it should examine the &v4l2-buffer; +<structfield>timestamp</structfield> of captured buffers, or set the +field before enqueuing buffers for output.</para> + + <para>Drivers implementing memory mapping I/O must +support the <constant>VIDIOC_REQBUFS</constant>, +<constant>VIDIOC_QUERYBUF</constant>, +<constant>VIDIOC_QBUF</constant>, <constant>VIDIOC_DQBUF</constant>, +<constant>VIDIOC_STREAMON</constant> and +<constant>VIDIOC_STREAMOFF</constant> ioctl, the +<function>mmap()</function>, <function>munmap()</function>, +<function>select()</function> and <function>poll()</function> +function.<footnote> + <para>At the driver level <function>select()</function> and +<function>poll()</function> are the same, and +<function>select()</function> is too important to be optional. The +rest should be evident.</para> + </footnote></para> + + <para>[capture example]</para> + + </section> + + <section id="userp"> + <title>Streaming I/O (User Pointers)</title> + + <para>Input and output devices support this I/O method when the +<constant>V4L2_CAP_STREAMING</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl is set. If the particular user +pointer method (not only memory mapping) is supported must be +determined by calling the &VIDIOC-REQBUFS; ioctl.</para> + + <para>This I/O method combines advantages of the read/write and +memory mapping methods. Buffers are allocated by the application +itself, and can reside for example in virtual or shared memory. Only +pointers to data are exchanged, these pointers and meta-information +are passed in &v4l2-buffer;. The driver must be switched +into user pointer I/O mode by calling the &VIDIOC-REQBUFS; with the +desired buffer type. No buffers are allocated beforehands, +consequently they are not indexed and cannot be queried like mapped +buffers with the <constant>VIDIOC_QUERYBUF</constant> ioctl.</para> + + <example> + <title>Initiating streaming I/O with user pointers</title> + + <programlisting> +&v4l2-requestbuffers; reqbuf; + +memset (&reqbuf, 0, sizeof (reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +reqbuf.memory = V4L2_MEMORY_USERPTR; + +if (ioctl (fd, &VIDIOC-REQBUFS;, &reqbuf) == -1) { + if (errno == EINVAL) + printf ("Video capturing or user pointer streaming is not supported\n"); + else + perror ("VIDIOC_REQBUFS"); + + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <para>Buffer addresses and sizes are passed on the fly with the +&VIDIOC-QBUF; ioctl. Although buffers are commonly cycled, +applications can pass different addresses and sizes at each +<constant>VIDIOC_QBUF</constant> call. If required by the hardware the +driver swaps memory pages within physical memory to create a +continuous area of memory. This happens transparently to the +application in the virtual memory subsystem of the kernel. When buffer +pages have been swapped out to disk they are brought back and finally +locked in physical memory for DMA.<footnote> + <para>We expect that frequently used buffers are typically not +swapped out. Anyway, the process of swapping, locking or generating +scatter-gather lists may be time consuming. The delay can be masked by +the depth of the incoming buffer queue, and perhaps by maintaining +caches assuming a buffer will be soon enqueued again. On the other +hand, to optimize memory usage drivers can limit the number of buffers +locked in advance and recycle the most recently used buffers first. Of +course, the pages of empty buffers in the incoming queue need not be +saved to disk. Output buffers must be saved on the incoming and +outgoing queue because an application may share them with other +processes.</para> + </footnote></para> + + <para>Filled or displayed buffers are dequeued with the +&VIDIOC-DQBUF; ioctl. The driver can unlock the memory pages at any +time between the completion of the DMA and this ioctl. The memory is +also unlocked when &VIDIOC-STREAMOFF; is called, &VIDIOC-REQBUFS;, or +when the device is closed. Applications must take care not to free +buffers without dequeuing. For once, the buffers remain locked until +further, wasting physical memory. Second the driver will not be +notified when the memory is returned to the application's free list +and subsequently reused for other purposes, possibly completing the +requested DMA and overwriting valuable data.</para> + + <para>For capturing applications it is customary to enqueue a +number of empty buffers, to start capturing and enter the read loop. +Here the application waits until a filled buffer can be dequeued, and +re-enqueues the buffer when the data is no longer needed. Output +applications fill and enqueue buffers, when enough buffers are stacked +up output is started. In the write loop, when the application +runs out of free buffers it must wait until an empty buffer can be +dequeued and reused. Two methods exist to suspend execution of the +application until one or more buffers can be dequeued. By default +<constant>VIDIOC_DQBUF</constant> blocks when no buffer is in the +outgoing queue. When the <constant>O_NONBLOCK</constant> flag was +given to the &func-open; function, <constant>VIDIOC_DQBUF</constant> +returns immediately with an &EAGAIN; when no buffer is available. The +&func-select; or &func-poll; function are always available.</para> + + <para>To start and stop capturing or output applications call the +&VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctl. Note +<constant>VIDIOC_STREAMOFF</constant> removes all buffers from both +queues and unlocks all buffers as a side effect. Since there is no +notion of doing anything "now" on a multitasking system, if an +application needs to synchronize with another event it should examine +the &v4l2-buffer; <structfield>timestamp</structfield> of captured +buffers, or set the field before enqueuing buffers for output.</para> + + <para>Drivers implementing user pointer I/O must +support the <constant>VIDIOC_REQBUFS</constant>, +<constant>VIDIOC_QBUF</constant>, <constant>VIDIOC_DQBUF</constant>, +<constant>VIDIOC_STREAMON</constant> and +<constant>VIDIOC_STREAMOFF</constant> ioctl, the +<function>select()</function> and <function>poll()</function> function.<footnote> + <para>At the driver level <function>select()</function> and +<function>poll()</function> are the same, and +<function>select()</function> is too important to be optional. The +rest should be evident.</para> + </footnote></para> + </section> + + <section id="async"> + <title>Asynchronous I/O</title> + + <para>This method is not defined yet.</para> + </section> + + <section id="buffer"> + <title>Buffers</title> + + <para>A buffer contains data exchanged by application and +driver using one of the Streaming I/O methods. Only pointers to +buffers are exchanged, the data itself is not copied. These pointers, +together with meta-information like timestamps or field parity, are +stored in a struct <structname>v4l2_buffer</structname>, argument to +the &VIDIOC-QUERYBUF;, &VIDIOC-QBUF; and &VIDIOC-DQBUF; ioctl.</para> + + <para>Nominally timestamps refer to the first data byte transmitted. +In practice however the wide range of hardware covered by the V4L2 API +limits timestamp accuracy. Often an interrupt routine will +sample the system clock shortly after the field or frame was stored +completely in memory. So applications must expect a constant +difference up to one field or frame period plus a small (few scan +lines) random error. The delay and error can be much +larger due to compression or transmission over an external bus when +the frames are not properly stamped by the sender. This is frequently +the case with USB cameras. Here timestamps refer to the instant the +field or frame was received by the driver, not the capture time. These +devices identify by not enumerating any video standards, see <xref +linkend="standard" />.</para> + + <para>Similar limitations apply to output timestamps. Typically +the video hardware locks to a clock controlling the video timing, the +horizontal and vertical synchronization pulses. At some point in the +line sequence, possibly the vertical blanking, an interrupt routine +samples the system clock, compares against the timestamp and programs +the hardware to repeat the previous field or frame, or to display the +buffer contents.</para> + + <para>Apart of limitations of the video device and natural +inaccuracies of all clocks, it should be noted system time itself is +not perfectly stable. It can be affected by power saving cycles, +warped to insert leap seconds, or even turned back or forth by the +system administrator affecting long term measurements. <footnote> + <para>Since no other Linux multimedia +API supports unadjusted time it would be foolish to introduce here. We +must use a universally supported clock to synchronize different media, +hence time of day.</para> + </footnote></para> + + <table frame="none" pgwide="1" id="v4l2-buffer"> + <title>struct <structname>v4l2_buffer</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry></entry> + <entry>Number of the buffer, set by the application. This +field is only used for <link linkend="mmap">memory mapping</link> I/O +and can range from zero to the number of buffers allocated +with the &VIDIOC-REQBUFS; ioctl (&v4l2-requestbuffers; <structfield>count</structfield>) minus one.</entry> + </row> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>Type of the buffer, same as &v4l2-format; +<structfield>type</structfield> or &v4l2-requestbuffers; +<structfield>type</structfield>, set by the application.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>bytesused</structfield></entry> + <entry></entry> + <entry>The number of bytes occupied by the data in the +buffer. It depends on the negotiated data format and may change with +each buffer for compressed variable size data like JPEG images. +Drivers must set this field when <structfield>type</structfield> +refers to an input stream, applications when an output stream.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry></entry> + <entry>Flags set by the application or driver, see <xref +linkend="buffer-flags" />.</entry> + </row> + <row> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry></entry> + <entry>Indicates the field order of the image in the +buffer, see <xref linkend="v4l2-field" />. This field is not used when +the buffer contains VBI data. Drivers must set it when +<structfield>type</structfield> refers to an input stream, +applications when an output stream.</entry> + </row> + <row> + <entry>struct timeval</entry> + <entry><structfield>timestamp</structfield></entry> + <entry></entry> + <entry><para>For input streams this is the +system time (as returned by the <function>gettimeofday()</function> +function) when the first data byte was captured. For output streams +the data will not be displayed before this time, secondary to the +nominal frame rate determined by the current video standard in +enqueued order. Applications can for example zero this field to +display frames as soon as possible. The driver stores the time at +which the first data byte was actually sent out in the +<structfield>timestamp</structfield> field. This permits +applications to monitor the drift between the video and system +clock.</para></entry> + </row> + <row> + <entry>&v4l2-timecode;</entry> + <entry><structfield>timecode</structfield></entry> + <entry></entry> + <entry>When <structfield>type</structfield> is +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant> and the +<constant>V4L2_BUF_FLAG_TIMECODE</constant> flag is set in +<structfield>flags</structfield>, this structure contains a frame +timecode. In <link linkend="v4l2-field">V4L2_FIELD_ALTERNATE</link> +mode the top and bottom field contain the same timecode. +Timecodes are intended to help video editing and are typically recorded on +video tapes, but also embedded in compressed formats like MPEG. This +field is independent of the <structfield>timestamp</structfield> and +<structfield>sequence</structfield> fields.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>sequence</structfield></entry> + <entry></entry> + <entry>Set by the driver, counting the frames in the +sequence.</entry> + </row> + <row> + <entry spanname="hspan"><para>In <link +linkend="v4l2-field">V4L2_FIELD_ALTERNATE</link> mode the top and +bottom field have the same sequence number. The count starts at zero +and includes dropped or repeated frames. A dropped frame was received +by an input device but could not be stored due to lack of free buffer +space. A repeated frame was displayed again by an output device +because the application did not pass new data in +time.</para><para>Note this may count the frames received +e.g. over USB, without taking into account the frames dropped by the +remote hardware due to limited compression throughput or bus +bandwidth. These devices identify by not enumerating any video +standards, see <xref linkend="standard" />.</para></entry> + </row> + <row> + <entry>&v4l2-memory;</entry> + <entry><structfield>memory</structfield></entry> + <entry></entry> + <entry>This field must be set by applications and/or drivers +in accordance with the selected I/O method.</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield>m</structfield></entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>offset</structfield></entry> + <entry>When <structfield>memory</structfield> is +<constant>V4L2_MEMORY_MMAP</constant> this is the offset of the buffer +from the start of the device memory. The value is returned by the +driver and apart of serving as parameter to the &func-mmap; function +not useful for applications. See <xref linkend="mmap" /> for details.</entry> + </row> + <row> + <entry></entry> + <entry>unsigned long</entry> + <entry><structfield>userptr</structfield></entry> + <entry>When <structfield>memory</structfield> is +<constant>V4L2_MEMORY_USERPTR</constant> this is a pointer to the +buffer (casted to unsigned long type) in virtual memory, set by the +application. See <xref linkend="userp" /> for details.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>length</structfield></entry> + <entry></entry> + <entry>Size of the buffer (not the payload) in bytes.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>input</structfield></entry> + <entry></entry> + <entry>Some video capture drivers support rapid and +synchronous video input changes, a function useful for example in +video surveillance applications. For this purpose applications set the +<constant>V4L2_BUF_FLAG_INPUT</constant> flag, and this field to the +number of a video input as in &v4l2-input; field +<structfield>index</structfield>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield></entry> + <entry></entry> + <entry>A place holder for future extensions and custom +(driver defined) buffer types +<constant>V4L2_BUF_TYPE_PRIVATE</constant> and higher.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="v4l2-buf-type"> + <title>enum v4l2_buf_type</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant></entry> + <entry>1</entry> + <entry>Buffer of a video capture stream, see <xref + linkend="capture" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant></entry> + <entry>2</entry> + <entry>Buffer of a video output stream, see <xref + linkend="output" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant></entry> + <entry>3</entry> + <entry>Buffer for video overlay, see <xref linkend="overlay" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VBI_CAPTURE</constant></entry> + <entry>4</entry> + <entry>Buffer of a raw VBI capture stream, see <xref + linkend="raw-vbi" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant></entry> + <entry>5</entry> + <entry>Buffer of a raw VBI output stream, see <xref + linkend="raw-vbi" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant></entry> + <entry>6</entry> + <entry>Buffer of a sliced VBI capture stream, see <xref + linkend="sliced" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant></entry> + <entry>7</entry> + <entry>Buffer of a sliced VBI output stream, see <xref + linkend="sliced" />.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY</constant></entry> + <entry>8</entry> + <entry>Buffer for video output overlay (OSD), see <xref + linkend="osd" />. Status: <link +linkend="experimental">Experimental</link>.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_TYPE_PRIVATE</constant></entry> + <entry>0x80</entry> + <entry>This and higher values are reserved for custom +(driver defined) buffer types.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="buffer-flags"> + <title>Buffer Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_BUF_FLAG_MAPPED</constant></entry> + <entry>0x0001</entry> + <entry>The buffer resides in device memory and has been mapped +into the application's address space, see <xref linkend="mmap" /> for details. +Drivers set or clear this flag when the +<link linkend="vidioc-querybuf">VIDIOC_QUERYBUF</link>, <link + linkend="vidioc-qbuf">VIDIOC_QBUF</link> or <link + linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl is called. Set by the driver.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_QUEUED</constant></entry> + <entry>0x0002</entry> + <entry>Internally drivers maintain two buffer queues, an +incoming and outgoing queue. When this flag is set, the buffer is +currently on the incoming queue. It automatically moves to the +outgoing queue after the buffer has been filled (capture devices) or +displayed (output devices). Drivers set or clear this flag when the +<constant>VIDIOC_QUERYBUF</constant> ioctl is called. After +(successful) calling the <constant>VIDIOC_QBUF </constant>ioctl it is +always set and after <constant>VIDIOC_DQBUF</constant> always +cleared.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_DONE</constant></entry> + <entry>0x0004</entry> + <entry>When this flag is set, the buffer is currently on +the outgoing queue, ready to be dequeued from the driver. Drivers set +or clear this flag when the <constant>VIDIOC_QUERYBUF</constant> ioctl +is called. After calling the <constant>VIDIOC_QBUF</constant> or +<constant>VIDIOC_DQBUF</constant> it is always cleared. Of course a +buffer cannot be on both queues at the same time, the +<constant>V4L2_BUF_FLAG_QUEUED</constant> and +<constant>V4L2_BUF_FLAG_DONE</constant> flag are mutually exclusive. +They can be both cleared however, then the buffer is in "dequeued" +state, in the application domain to say so.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_KEYFRAME</constant></entry> + <entry>0x0008</entry> + <entry>Drivers set or clear this flag when calling the +<constant>VIDIOC_DQBUF</constant> ioctl. It may be set by video +capture devices when the buffer contains a compressed image which is a +key frame (or field), &ie; can be decompressed on its own.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_PFRAME</constant></entry> + <entry>0x0010</entry> + <entry>Similar to <constant>V4L2_BUF_FLAG_KEYFRAME</constant> +this flags predicted frames or fields which contain only differences to a +previous key frame.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_BFRAME</constant></entry> + <entry>0x0020</entry> + <entry>Similar to <constant>V4L2_BUF_FLAG_PFRAME</constant> + this is a bidirectional predicted frame or field. [ooc tbd]</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_TIMECODE</constant></entry> + <entry>0x0100</entry> + <entry>The <structfield>timecode</structfield> field is valid. +Drivers set or clear this flag when the <constant>VIDIOC_DQBUF</constant> +ioctl is called.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_INPUT</constant></entry> + <entry>0x0200</entry> + <entry>The <structfield>input</structfield> field is valid. +Applications set or clear this flag before calling the +<constant>VIDIOC_QBUF</constant> ioctl.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-memory"> + <title>enum v4l2_memory</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_MEMORY_MMAP</constant></entry> + <entry>1</entry> + <entry>The buffer is used for <link linkend="mmap">memory +mapping</link> I/O.</entry> + </row> + <row> + <entry><constant>V4L2_MEMORY_USERPTR</constant></entry> + <entry>2</entry> + <entry>The buffer is used for <link linkend="userp">user +pointer</link> I/O.</entry> + </row> + <row> + <entry><constant>V4L2_MEMORY_OVERLAY</constant></entry> + <entry>3</entry> + <entry>[to do]</entry> + </row> + </tbody> + </tgroup> + </table> + + <section> + <title>Timecodes</title> + + <para>The <structname>v4l2_timecode</structname> structure is +designed to hold a <xref linkend="smpte12m" /> or similar timecode. +(struct <structname>timeval</structname> timestamps are stored in +&v4l2-buffer; field <structfield>timestamp</structfield>.)</para> + + <table frame="none" pgwide="1" id="v4l2-timecode"> + <title>struct <structname>v4l2_timecode</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>Frame rate the timecodes are based on, see <xref + linkend="timecode-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Timecode flags, see <xref linkend="timecode-flags" />.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>frames</structfield></entry> + <entry>Frame count, 0 ... 23/24/29/49/59, depending on the + type of timecode.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>seconds</structfield></entry> + <entry>Seconds count, 0 ... 59. This is a binary, not BCD number.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>minutes</structfield></entry> + <entry>Minutes count, 0 ... 59. This is a binary, not BCD number.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>hours</structfield></entry> + <entry>Hours count, 0 ... 29. This is a binary, not BCD number.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>userbits</structfield>[4]</entry> + <entry>The "user group" bits from the timecode.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="timecode-type"> + <title>Timecode Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TC_TYPE_24FPS</constant></entry> + <entry>1</entry> + <entry>24 frames per second, i. e. film.</entry> + </row> + <row> + <entry><constant>V4L2_TC_TYPE_25FPS</constant></entry> + <entry>2</entry> + <entry>25 frames per second, &ie; PAL or SECAM video.</entry> + </row> + <row> + <entry><constant>V4L2_TC_TYPE_30FPS</constant></entry> + <entry>3</entry> + <entry>30 frames per second, &ie; NTSC video.</entry> + </row> + <row> + <entry><constant>V4L2_TC_TYPE_50FPS</constant></entry> + <entry>4</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_TC_TYPE_60FPS</constant></entry> + <entry>5</entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="timecode-flags"> + <title>Timecode Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TC_FLAG_DROPFRAME</constant></entry> + <entry>0x0001</entry> + <entry>Indicates "drop frame" semantics for counting frames +in 29.97 fps material. When set, frame numbers 0 and 1 at the start of +each minute, except minutes 0, 10, 20, 30, 40, 50 are omitted from the +count.</entry> + </row> + <row> + <entry><constant>V4L2_TC_FLAG_COLORFRAME</constant></entry> + <entry>0x0002</entry> + <entry>The "color frame" flag.</entry> + </row> + <row> + <entry><constant>V4L2_TC_USERBITS_field</constant></entry> + <entry>0x000C</entry> + <entry>Field mask for the "binary group flags".</entry> + </row> + <row> + <entry><constant>V4L2_TC_USERBITS_USERDEFINED</constant></entry> + <entry>0x0000</entry> + <entry>Unspecified format.</entry> + </row> + <row> + <entry><constant>V4L2_TC_USERBITS_8BITCHARS</constant></entry> + <entry>0x0008</entry> + <entry>8-bit ISO characters.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + </section> + + <section id="field-order"> + <title>Field Order</title> + + <para>We have to distinguish between progressive and interlaced +video. Progressive video transmits all lines of a video image +sequentially. Interlaced video divides an image into two fields, +containing only the odd and even lines of the image, respectively. +Alternating the so called odd and even field are transmitted, and due +to a small delay between fields a cathode ray TV displays the lines +interleaved, yielding the original frame. This curious technique was +invented because at refresh rates similar to film the image would +fade out too quickly. Transmitting fields reduces the flicker without +the necessity of doubling the frame rate and with it the bandwidth +required for each channel.</para> + + <para>It is important to understand a video camera does not expose +one frame at a time, merely transmitting the frames separated into +fields. The fields are in fact captured at two different instances in +time. An object on screen may well move between one field and the +next. For applications analysing motion it is of paramount importance +to recognize which field of a frame is older, the <emphasis>temporal +order</emphasis>.</para> + + <para>When the driver provides or accepts images field by field +rather than interleaved, it is also important applications understand +how the fields combine to frames. We distinguish between top and +bottom fields, the <emphasis>spatial order</emphasis>: The first line +of the top field is the first line of an interlaced frame, the first +line of the bottom field is the second line of that frame.</para> + + <para>However because fields were captured one after the other, +arguing whether a frame commences with the top or bottom field is +pointless. Any two successive top and bottom, or bottom and top fields +yield a valid frame. Only when the source was progressive to begin +with, ⪚ when transferring film to video, two fields may come from +the same frame, creating a natural order.</para> + + <para>Counter to intuition the top field is not necessarily the +older field. Whether the older field contains the top or bottom lines +is a convention determined by the video standard. Hence the +distinction between temporal and spatial order of fields. The diagrams +below should make this clearer.</para> + + <para>All video capture and output devices must report the current +field order. Some drivers may permit the selection of a different +order, to this end applications initialize the +<structfield>field</structfield> field of &v4l2-pix-format; before +calling the &VIDIOC-S-FMT; ioctl. If this is not desired it should +have the value <constant>V4L2_FIELD_ANY</constant> (0).</para> + + <table frame="none" pgwide="1" id="v4l2-field"> + <title>enum v4l2_field</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FIELD_ANY</constant></entry> + <entry>0</entry> + <entry>Applications request this field order when any +one of the <constant>V4L2_FIELD_NONE</constant>, +<constant>V4L2_FIELD_TOP</constant>, +<constant>V4L2_FIELD_BOTTOM</constant>, or +<constant>V4L2_FIELD_INTERLACED</constant> formats is acceptable. +Drivers choose depending on hardware capabilities or e. g. the +requested image size, and return the actual field order. &v4l2-buffer; +<structfield>field</structfield> can never be +<constant>V4L2_FIELD_ANY</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_NONE</constant></entry> + <entry>1</entry> + <entry>Images are in progressive format, not interlaced. +The driver may also indicate this order when it cannot distinguish +between <constant>V4L2_FIELD_TOP</constant> and +<constant>V4L2_FIELD_BOTTOM</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_TOP</constant></entry> + <entry>2</entry> + <entry>Images consist of the top field only.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_BOTTOM</constant></entry> + <entry>3</entry> + <entry>Images consist of the bottom field only. +Applications may wish to prevent a device from capturing interlaced +images because they will have "comb" or "feathering" artefacts around +moving objects.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_INTERLACED</constant></entry> + <entry>4</entry> + <entry>Images contain both fields, interleaved line by +line. The temporal order of the fields (whether the top or bottom +field is first transmitted) depends on the current video standard. +M/NTSC transmits the bottom field first, all other standards the top +field first.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_SEQ_TB</constant></entry> + <entry>5</entry> + <entry>Images contain both fields, the top field lines +are stored first in memory, immediately followed by the bottom field +lines. Fields are always stored in temporal order, the older one first +in memory. Image sizes refer to the frame, not fields.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_SEQ_BT</constant></entry> + <entry>6</entry> + <entry>Images contain both fields, the bottom field +lines are stored first in memory, immediately followed by the top +field lines. Fields are always stored in temporal order, the older one +first in memory. Image sizes refer to the frame, not fields.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_ALTERNATE</constant></entry> + <entry>7</entry> + <entry>The two fields of a frame are passed in separate +buffers, in temporal order, &ie; the older one first. To indicate the field +parity (whether the current field is a top or bottom field) the driver +or application, depending on data direction, must set &v4l2-buffer; +<structfield>field</structfield> to +<constant>V4L2_FIELD_TOP</constant> or +<constant>V4L2_FIELD_BOTTOM</constant>. Any two successive fields pair +to build a frame. If fields are successive, without any dropped fields +between them (fields can drop individually), can be determined from +the &v4l2-buffer; <structfield>sequence</structfield> field. Image +sizes refer to the frame, not fields. This format cannot be selected +when using the read/write I/O method.<!-- Where it's indistinguishable +from V4L2_FIELD_SEQ_*. --></entry> + </row> + <row> + <entry><constant>V4L2_FIELD_INTERLACED_TB</constant></entry> + <entry>8</entry> + <entry>Images contain both fields, interleaved line by +line, top field first. The top field is transmitted first.</entry> + </row> + <row> + <entry><constant>V4L2_FIELD_INTERLACED_BT</constant></entry> + <entry>9</entry> + <entry>Images contain both fields, interleaved line by +line, top field first. The bottom field is transmitted first.</entry> + </row> + </tbody> + </tgroup> + </table> + + <figure id="fieldseq-tb"> + <title>Field Order, Top Field First Transmitted</title> + <mediaobject> + <imageobject> + <imagedata fileref="fieldseq_tb.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="fieldseq_tb.gif" format="GIF" /> + </imageobject> + </mediaobject> + </figure> + + <figure id="fieldseq-bt"> + <title>Field Order, Bottom Field First Transmitted</title> + <mediaobject> + <imageobject> + <imagedata fileref="fieldseq_bt.pdf" format="PS" /> + </imageobject> + <imageobject> + <imagedata fileref="fieldseq_bt.gif" format="GIF" /> + </imageobject> + </mediaobject> + </figure> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/keytable.c.xml b/Documentation/DocBook/v4l/keytable.c.xml new file mode 100644 index 0000000..d53254a --- /dev/null +++ b/Documentation/DocBook/v4l/keytable.c.xml @@ -0,0 +1,172 @@ +<programlisting> +/* keytable.c - This program allows checking/replacing keys at IR + + Copyright (C) 2006-2009 Mauro Carvalho Chehab <mchehab@infradead.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + */ + +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <linux/input.h> +#include <sys/ioctl.h> + +#include "parse.h" + +void prtcode (int *codes) +{ + struct parse_key *p; + + for (p=keynames;p->name!=NULL;p++) { + if (p->value == (unsigned)codes[1]) { + printf("scancode 0x%04x = %s (0x%02x)\n", codes[0], p->name, codes[1]); + return; + } + } + + if (isprint (codes[1])) + printf("scancode %d = '%c' (0x%02x)\n", codes[0], codes[1], codes[1]); + else + printf("scancode %d = 0x%02x\n", codes[0], codes[1]); +} + +int parse_code(char *string) +{ + struct parse_key *p; + + for (p=keynames;p->name!=NULL;p++) { + if (!strcasecmp(p->name, string)) { + return p->value; + } + } + return -1; +} + +int main (int argc, char *argv[]) +{ + int fd; + unsigned int i, j; + int codes[2]; + + if (argc<2 || argc>4) { + printf ("usage: %s <device> to get table; or\n" + " %s <device> <scancode> <keycode>\n" + " %s <device> <keycode_file>\n",*argv,*argv,*argv); + return -1; + } + + if ((fd = open(argv[1], O_RDONLY)) < 0) { + perror("Couldn't open input device"); + return(-1); + } + + if (argc==4) { + int value; + + value=parse_code(argv[3]); + + if (value==-1) { + value = strtol(argv[3], NULL, 0); + if (errno) + perror("value"); + } + + codes [0] = (unsigned) strtol(argv[2], NULL, 0); + codes [1] = (unsigned) value; + + if(ioctl(fd, EVIOCSKEYCODE, codes)) + perror ("EVIOCSKEYCODE"); + + if(ioctl(fd, EVIOCGKEYCODE, codes)==0) + prtcode(codes); + return 0; + } + + if (argc==3) { + FILE *fin; + int value; + char *scancode, *keycode, s[2048]; + + fin=fopen(argv[2],"r"); + if (fin==NULL) { + perror ("opening keycode file"); + return -1; + } + + /* Clears old table */ + for (j = 0; j < 256; j++) { + for (i = 0; i < 256; i++) { + codes[0] = (j << 8) | i; + codes[1] = KEY_RESERVED; + ioctl(fd, EVIOCSKEYCODE, codes); + } + } + + while (fgets(s,sizeof(s),fin)) { + scancode=strtok(s,"\n\t =:"); + if (!scancode) { + perror ("parsing input file scancode"); + return -1; + } + if (!strcasecmp(scancode, "scancode")) { + scancode = strtok(NULL,"\n\t =:"); + if (!scancode) { + perror ("parsing input file scancode"); + return -1; + } + } + + keycode=strtok(NULL,"\n\t =:("); + if (!keycode) { + perror ("parsing input file keycode"); + return -1; + } + + // printf ("parsing %s=%s:", scancode, keycode); + value=parse_code(keycode); + // printf ("\tvalue=%d\n",value); + + if (value==-1) { + value = strtol(keycode, NULL, 0); + if (errno) + perror("value"); + } + + codes [0] = (unsigned) strtol(scancode, NULL, 0); + codes [1] = (unsigned) value; + + // printf("\t%04x=%04x\n",codes[0], codes[1]); + if(ioctl(fd, EVIOCSKEYCODE, codes)) { + fprintf(stderr, "Setting scancode 0x%04x with 0x%04x via ",codes[0], codes[1]); + perror ("EVIOCSKEYCODE"); + } + + if(ioctl(fd, EVIOCGKEYCODE, codes)==0) + prtcode(codes); + } + return 0; + } + + /* Get scancode table */ + for (j = 0; j < 256; j++) { + for (i = 0; i < 256; i++) { + codes[0] = (j << 8) | i; + if (!ioctl(fd, EVIOCGKEYCODE, codes) && codes[1] != KEY_RESERVED) + prtcode(codes); + } + } + return 0; +} + +</programlisting> diff --git a/Documentation/DocBook/v4l/libv4l.xml b/Documentation/DocBook/v4l/libv4l.xml new file mode 100644 index 0000000..c14fc3d --- /dev/null +++ b/Documentation/DocBook/v4l/libv4l.xml @@ -0,0 +1,167 @@ +<title>Libv4l Userspace Library</title> +<section id="libv4l-introduction"> + <title>Introduction</title> + + <para>libv4l is a collection of libraries which adds a thin abstraction +layer on top of video4linux2 devices. The purpose of this (thin) layer +is to make it easy for application writers to support a wide variety of +devices without having to write separate code for different devices in the +same class.</para> +<para>An example of using libv4l is provided by +<link linkend='v4l2grab-example'>v4l2grab</link>. +</para> + + <para>libv4l consists of 3 different libraries:</para> + <section> + <title>libv4lconvert</title> + + <para>libv4lconvert is a library that converts several +different pixelformats found in V4L2 drivers into a few common RGB and +YUY formats.</para> + <para>It currently accepts the following V4L2 driver formats: +<link linkend="V4L2-PIX-FMT-BGR24"><constant>V4L2_PIX_FMT_BGR24</constant></link>, +<link linkend="V4L2-PIX-FMT-HM12"><constant>V4L2_PIX_FMT_HM12</constant></link>, +<link linkend="V4L2-PIX-FMT-JPEG"><constant>V4L2_PIX_FMT_JPEG</constant></link>, +<link linkend="V4L2-PIX-FMT-MJPEG"><constant>V4L2_PIX_FMT_MJPEG</constant></link>, +<link linkend="V4L2-PIX-FMT-MR97310A"><constant>V4L2_PIX_FMT_MR97310A</constant></link>, +<link linkend="V4L2-PIX-FMT-OV511"><constant>V4L2_PIX_FMT_OV511</constant></link>, +<link linkend="V4L2-PIX-FMT-OV518"><constant>V4L2_PIX_FMT_OV518</constant></link>, +<link linkend="V4L2-PIX-FMT-PAC207"><constant>V4L2_PIX_FMT_PAC207</constant></link>, +<link linkend="V4L2-PIX-FMT-PJPG"><constant>V4L2_PIX_FMT_PJPG</constant></link>, +<link linkend="V4L2-PIX-FMT-RGB24"><constant>V4L2_PIX_FMT_RGB24</constant></link>, +<link linkend="V4L2-PIX-FMT-SBGGR8"><constant>V4L2_PIX_FMT_SBGGR8</constant></link>, +<link linkend="V4L2-PIX-FMT-SGBRG8"><constant>V4L2_PIX_FMT_SGBRG8</constant></link>, +<link linkend="V4L2-PIX-FMT-SGRBG8"><constant>V4L2_PIX_FMT_SGRBG8</constant></link>, +<link linkend="V4L2-PIX-FMT-SN9C10X"><constant>V4L2_PIX_FMT_SN9C10X</constant></link>, +<link linkend="V4L2-PIX-FMT-SN9C20X-I420"><constant>V4L2_PIX_FMT_SN9C20X_I420</constant></link>, +<link linkend="V4L2-PIX-FMT-SPCA501"><constant>V4L2_PIX_FMT_SPCA501</constant></link>, +<link linkend="V4L2-PIX-FMT-SPCA505"><constant>V4L2_PIX_FMT_SPCA505</constant></link>, +<link linkend="V4L2-PIX-FMT-SPCA508"><constant>V4L2_PIX_FMT_SPCA508</constant></link>, +<link linkend="V4L2-PIX-FMT-SPCA561"><constant>V4L2_PIX_FMT_SPCA561</constant></link>, +<link linkend="V4L2-PIX-FMT-SQ905C"><constant>V4L2_PIX_FMT_SQ905C</constant></link>, +<constant>V4L2_PIX_FMT_SRGGB8</constant>, +<link linkend="V4L2-PIX-FMT-UYVY"><constant>V4L2_PIX_FMT_UYVY</constant></link>, +<link linkend="V4L2-PIX-FMT-YUV420"><constant>V4L2_PIX_FMT_YUV420</constant></link>, +<link linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link>, +<link linkend="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></link>, +and <link linkend="V4L2-PIX-FMT-YVYU"><constant>V4L2_PIX_FMT_YVYU</constant></link>. +</para> + <para>Later on libv4lconvert was expanded to also be able to do +various video processing functions to improve webcam video quality. +The video processing is split in to 2 parts: libv4lconvert/control and +libv4lconvert/processing.</para> + + <para>The control part is used to offer video controls which can +be used to control the video processing functions made available by + libv4lconvert/processing. These controls are stored application wide +(until reboot) by using a persistent shared memory object.</para> + + <para>libv4lconvert/processing offers the actual video +processing functionality.</para> + </section> + <section> + <title>libv4l1</title> + <para>This library offers functions that can be used to quickly +make v4l1 applications work with v4l2 devices. These functions work exactly +like the normal open/close/etc, except that libv4l1 does full emulation of +the v4l1 api on top of v4l2 drivers, in case of v4l1 drivers it +will just pass calls through.</para> + <para>Since those functions are emulations of the old V4L1 API, +it shouldn't be used for new applications.</para> + </section> + <section> + <title>libv4l2</title> + <para>This library should be used for all modern V4L2 +applications.</para> + <para>It provides handles to call V4L2 open/ioctl/close/poll +methods. Instead of just providing the raw output of the device, it enhances +the calls in the sense that it will use libv4lconvert to provide more video +formats and to enhance the image quality.</para> + <para>In most cases, libv4l2 just passes the calls directly +through to the v4l2 driver, intercepting the calls to +<link linkend='vidioc-g-fmt'><constant>VIDIOC_TRY_FMT</constant></link>, +<link linkend='vidioc-g-fmt'><constant>VIDIOC_G_FMT</constant></link> +<link linkend='vidioc-g-fmt'><constant>VIDIOC_S_FMT</constant></link> +<link linkend='vidioc-enum-framesizes'><constant>VIDIOC_ENUM_FRAMESIZES</constant></link> +and <link linkend='vidioc-enum-frameintervals'><constant>VIDIOC_ENUM_FRAMEINTERVALS</constant></link> +in order to emulate the formats +<link linkend="V4L2-PIX-FMT-BGR24"><constant>V4L2_PIX_FMT_BGR24</constant></link>, +<link linkend="V4L2-PIX-FMT-RGB24"><constant>V4L2_PIX_FMT_RGB24</constant></link>, +<link linkend="V4L2-PIX-FMT-YUV420"><constant>V4L2_PIX_FMT_YUV420</constant></link>, +and <link linkend="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></link>, +if they aren't available in the driver. +<link linkend='vidioc-enum-fmt'><constant>VIDIOC_ENUM_FMT</constant></link> +keeps enumerating the hardware supported formats, plus the emulated formats +offered by libv4l at the end. +</para> + <section id="libv4l-ops"> + <title>Libv4l device control functions</title> + <para>The common file operation methods are provided by +libv4l.</para> + <para>Those functions operate just like glibc +open/close/dup/ioctl/read/mmap/munmap:</para> +<itemizedlist><listitem> + <para>int v4l2_open(const char *file, int oflag, +...) - +operates like the standard <link linkend='func-open'>open()</link> function. +</para></listitem><listitem> + <para>int v4l2_close(int fd) - +operates like the standard <link linkend='func-close'>close()</link> function. +</para></listitem><listitem> + <para>int v4l2_dup(int fd) - +operates like the standard dup() function, duplicating a file handler. +</para></listitem><listitem> + <para>int v4l2_ioctl (int fd, unsigned long int request, ...) - +operates like the standard <link linkend='func-ioctl'>ioctl()</link> function. +</para></listitem><listitem> + <para>int v4l2_read (int fd, void* buffer, size_t n) - +operates like the standard <link linkend='func-read'>read()</link> function. +</para></listitem><listitem> + <para>void v4l2_mmap(void *start, size_t length, int prot, int flags, int fd, int64_t offset); - +operates like the standard <link linkend='func-mmap'>mmap()</link> function. +</para></listitem><listitem> + <para>int v4l2_munmap(void *_start, size_t length); - +operates like the standard <link linkend='func-munmap'>munmap()</link> function. +</para></listitem> +</itemizedlist> + <para>Those functions provide additional control:</para> +<itemizedlist><listitem> + <para>int v4l2_fd_open(int fd, int v4l2_flags) - +opens an already opened fd for further use through v4l2lib and possibly +modify libv4l2's default behavior through the v4l2_flags argument. +Currently, v4l2_flags can be <constant>V4L2_DISABLE_CONVERSION</constant>, +to disable format conversion. +</para></listitem><listitem> + <para>int v4l2_set_control(int fd, int cid, int value) - +This function takes a value of 0 - 65535, and then scales that range to +the actual range of the given v4l control id, and then if the cid exists +and is not locked sets the cid to the scaled value. +</para></listitem><listitem> + <para>int v4l2_get_control(int fd, int cid) - +This function returns a value of 0 - 65535, scaled to from the actual range +of the given v4l control id. when the cid does not exist, could not be +accessed for some reason, or some error occured 0 is returned. +</para></listitem> +</itemizedlist> + </section> + </section> + <section> + + <title>v4l1compat.so wrapper library</title> + + <para>This library intercepts calls to +open/close/ioctl/mmap/mmunmap operations and redirects them to the libv4l +counterparts, by using LD_PRELOAD=/usr/lib/v4l1compat.so. It also +emulates V4L1 calls via V4L2 API.</para> + <para>It allows usage of binary legacy applications that +still don't use libv4l.</para> + </section> + +</section> +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/pixfmt-grey.xml b/Documentation/DocBook/v4l/pixfmt-grey.xml new file mode 100644 index 0000000..3b72bc6 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-grey.xml @@ -0,0 +1,70 @@ + <refentry id="V4L2-PIX-FMT-GREY"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_GREY ('GREY')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_GREY</constant></refname> + <refpurpose>Grey-scale image</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is a grey-scale image. It is really a degenerate +Y'CbCr format which simply contains no Cb or Cr data.</para> + + <example> + <title><constant>V4L2_PIX_FMT_GREY</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-nv12.xml b/Documentation/DocBook/v4l/pixfmt-nv12.xml new file mode 100644 index 0000000..873f670 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-nv12.xml @@ -0,0 +1,151 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-NV12"><constant>V4L2_PIX_FMT_NV12</constant></refname> + <refname id="V4L2-PIX-FMT-NV21"><constant>V4L2_PIX_FMT_NV21</constant></refname> + <refpurpose>Formats with ½ horizontal and vertical +chroma resolution, also known as YUV 4:2:0. One luminance and one +chrominance plane with alternating chroma samples as opposed to +<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are two-plane versions of the YUV 4:2:0 format. +The three components are separated into two sub-images or planes. The +Y plane is first. The Y plane has one byte per pixel. For +<constant>V4L2_PIX_FMT_NV12</constant>, a combined CbCr plane +immediately follows the Y plane in memory. The CbCr plane is the same +width, in bytes, as the Y plane (and of the image), but is half as +tall in pixels. Each CbCr pair belongs to four pixels. For example, +Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to +Y'<subscript>00</subscript>, Y'<subscript>01</subscript>, +Y'<subscript>10</subscript>, Y'<subscript>11</subscript>. +<constant>V4L2_PIX_FMT_NV21</constant> is the same except the Cb and +Cr bytes are swapped, the CrCb plane starts with a Cr byte.</para> + + <para>If the Y plane has pad bytes after each row, then the +CbCr plane has as many pad bytes after its rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_NV12</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-nv16.xml b/Documentation/DocBook/v4l/pixfmt-nv16.xml new file mode 100644 index 0000000..2609403 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-nv16.xml @@ -0,0 +1,174 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_NV16 ('NV16'), V4L2_PIX_FMT_NV61 ('NV61')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-NV16"><constant>V4L2_PIX_FMT_NV16</constant></refname> + <refname id="V4L2-PIX-FMT-NV61"><constant>V4L2_PIX_FMT_NV61</constant></refname> + <refpurpose>Formats with ½ horizontal +chroma resolution, also known as YUV 4:2:2. One luminance and one +chrominance plane with alternating chroma samples as opposed to +<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are two-plane versions of the YUV 4:2:2 format. +The three components are separated into two sub-images or planes. The +Y plane is first. The Y plane has one byte per pixel. For +<constant>V4L2_PIX_FMT_NV16</constant>, a combined CbCr plane +immediately follows the Y plane in memory. The CbCr plane is the same +width and height, in bytes, as the Y plane (and of the image). +Each CbCr pair belongs to two pixels. For example, +Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to +Y'<subscript>00</subscript>, Y'<subscript>01</subscript>. +<constant>V4L2_PIX_FMT_NV61</constant> is the same except the Cb and +Cr bytes are swapped, the CrCb plane starts with a Cr byte.</para> + + <para>If the Y plane has pad bytes after each row, then the +CbCr plane has as many pad bytes after its rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_NV16</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 28:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-packed-rgb.xml b/Documentation/DocBook/v4l/pixfmt-packed-rgb.xml new file mode 100644 index 0000000..d2dd697 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-packed-rgb.xml @@ -0,0 +1,862 @@ +<refentry id="packed-rgb"> + <refmeta> + <refentrytitle>Packed RGB formats</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname>Packed RGB formats</refname> + <refpurpose>Packed RGB formats</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These formats are designed to match the pixel formats of +typical PC graphics frame buffers. They occupy 8, 16, 24 or 32 bits +per pixel. These are all packed-pixel formats, meaning all the data +for a pixel lie next to each other in memory.</para> + + <para>When one of these formats is used, drivers shall report the +colorspace <constant>V4L2_COLORSPACE_SRGB</constant>.</para> + + <table pgwide="1" frame="none" id="rgb-formats"> + <title>Packed RGB Image Formats</title> + <tgroup cols="37" align="center"> + <colspec colname="id" align="left" /> + <colspec colname="fourcc" /> + <colspec colname="bit" /> + + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + + <colspec colnum="13" colname="b17" align="center" /> + <colspec colnum="14" colname="b16" align="center" /> + <colspec colnum="15" colname="b15" align="center" /> + <colspec colnum="16" colname="b14" align="center" /> + <colspec colnum="17" colname="b13" align="center" /> + <colspec colnum="18" colname="b12" align="center" /> + <colspec colnum="19" colname="b11" align="center" /> + <colspec colnum="20" colname="b10" align="center" /> + + <colspec colnum="22" colname="b27" align="center" /> + <colspec colnum="23" colname="b26" align="center" /> + <colspec colnum="24" colname="b25" align="center" /> + <colspec colnum="25" colname="b24" align="center" /> + <colspec colnum="26" colname="b23" align="center" /> + <colspec colnum="27" colname="b22" align="center" /> + <colspec colnum="28" colname="b21" align="center" /> + <colspec colnum="29" colname="b20" align="center" /> + + <colspec colnum="31" colname="b37" align="center" /> + <colspec colnum="32" colname="b36" align="center" /> + <colspec colnum="33" colname="b35" align="center" /> + <colspec colnum="34" colname="b34" align="center" /> + <colspec colnum="35" colname="b33" align="center" /> + <colspec colnum="36" colname="b32" align="center" /> + <colspec colnum="37" colname="b31" align="center" /> + <colspec colnum="38" colname="b30" align="center" /> + + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <spanspec namest="b17" nameend="b10" spanname="b1" /> + <spanspec namest="b27" nameend="b20" spanname="b2" /> + <spanspec namest="b37" nameend="b30" spanname="b3" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry> </entry> + <entry spanname="b0">Byte 0 in memory</entry> + <entry spanname="b1">Byte 1</entry> + <entry spanname="b2">Byte 2</entry> + <entry spanname="b3">Byte 3</entry> + </row> + <row> + <entry> </entry> + <entry> </entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-RGB332"> + <entry><constant>V4L2_PIX_FMT_RGB332</constant></entry> + <entry>'RGB1'</entry> + <entry></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB444"> + <entry><constant>V4L2_PIX_FMT_RGB444</constant></entry> + <entry>'R444'</entry> + <entry></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB555"> + <entry><constant>V4L2_PIX_FMT_RGB555</constant></entry> + <entry>'RGBO'</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>a</entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB565"> + <entry><constant>V4L2_PIX_FMT_RGB565</constant></entry> + <entry>'RGBP'</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB555X"> + <entry><constant>V4L2_PIX_FMT_RGB555X</constant></entry> + <entry>'RGBQ'</entry> + <entry></entry> + <entry>a</entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB565X"> + <entry><constant>V4L2_PIX_FMT_RGB565X</constant></entry> + <entry>'RGBR'</entry> + <entry></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-BGR24"> + <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry> + <entry>'BGR3'</entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB24"> + <entry><constant>V4L2_PIX_FMT_RGB24</constant></entry> + <entry>'RGB3'</entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-BGR32"> + <entry><constant>V4L2_PIX_FMT_BGR32</constant></entry> + <entry>'BGR4'</entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + </row> + <row id="V4L2-PIX-FMT-RGB32"> + <entry><constant>V4L2_PIX_FMT_RGB32</constant></entry> + <entry>'RGB4'</entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Bit 7 is the most significant bit. The value of a = alpha +bits is undefined when reading from the driver, ignored when writing +to the driver, except when alpha blending has been negotiated for a +<link linkend="overlay">Video Overlay</link> or <link +linkend="osd">Video Output Overlay</link>.</para> + + <example> + <title><constant>V4L2_PIX_FMT_BGR24</constant> 4 × 4 pixel +image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="13" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>B<subscript>00</subscript></entry> + <entry>G<subscript>00</subscript></entry> + <entry>R<subscript>00</subscript></entry> + <entry>B<subscript>01</subscript></entry> + <entry>G<subscript>01</subscript></entry> + <entry>R<subscript>01</subscript></entry> + <entry>B<subscript>02</subscript></entry> + <entry>G<subscript>02</subscript></entry> + <entry>R<subscript>02</subscript></entry> + <entry>B<subscript>03</subscript></entry> + <entry>G<subscript>03</subscript></entry> + <entry>R<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>B<subscript>10</subscript></entry> + <entry>G<subscript>10</subscript></entry> + <entry>R<subscript>10</subscript></entry> + <entry>B<subscript>11</subscript></entry> + <entry>G<subscript>11</subscript></entry> + <entry>R<subscript>11</subscript></entry> + <entry>B<subscript>12</subscript></entry> + <entry>G<subscript>12</subscript></entry> + <entry>R<subscript>12</subscript></entry> + <entry>B<subscript>13</subscript></entry> + <entry>G<subscript>13</subscript></entry> + <entry>R<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>B<subscript>20</subscript></entry> + <entry>G<subscript>20</subscript></entry> + <entry>R<subscript>20</subscript></entry> + <entry>B<subscript>21</subscript></entry> + <entry>G<subscript>21</subscript></entry> + <entry>R<subscript>21</subscript></entry> + <entry>B<subscript>22</subscript></entry> + <entry>G<subscript>22</subscript></entry> + <entry>R<subscript>22</subscript></entry> + <entry>B<subscript>23</subscript></entry> + <entry>G<subscript>23</subscript></entry> + <entry>R<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 36:</entry> + <entry>B<subscript>30</subscript></entry> + <entry>G<subscript>30</subscript></entry> + <entry>R<subscript>30</subscript></entry> + <entry>B<subscript>31</subscript></entry> + <entry>G<subscript>31</subscript></entry> + <entry>R<subscript>31</subscript></entry> + <entry>B<subscript>32</subscript></entry> + <entry>G<subscript>32</subscript></entry> + <entry>R<subscript>32</subscript></entry> + <entry>B<subscript>33</subscript></entry> + <entry>G<subscript>33</subscript></entry> + <entry>R<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + + <important> + <para>Drivers may interpret these formats differently.</para> + </important> + + <para>Some RGB formats above are uncommon and were probably +defined in error. Drivers may interpret them as in <xref + linkend="rgb-formats-corrected" />.</para> + + <table pgwide="1" frame="none" id="rgb-formats-corrected"> + <title>Packed RGB Image Formats (corrected)</title> + <tgroup cols="37" align="center"> + <colspec colname="id" align="left" /> + <colspec colname="fourcc" /> + <colspec colname="bit" /> + + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + + <colspec colnum="13" colname="b17" align="center" /> + <colspec colnum="14" colname="b16" align="center" /> + <colspec colnum="15" colname="b15" align="center" /> + <colspec colnum="16" colname="b14" align="center" /> + <colspec colnum="17" colname="b13" align="center" /> + <colspec colnum="18" colname="b12" align="center" /> + <colspec colnum="19" colname="b11" align="center" /> + <colspec colnum="20" colname="b10" align="center" /> + + <colspec colnum="22" colname="b27" align="center" /> + <colspec colnum="23" colname="b26" align="center" /> + <colspec colnum="24" colname="b25" align="center" /> + <colspec colnum="25" colname="b24" align="center" /> + <colspec colnum="26" colname="b23" align="center" /> + <colspec colnum="27" colname="b22" align="center" /> + <colspec colnum="28" colname="b21" align="center" /> + <colspec colnum="29" colname="b20" align="center" /> + + <colspec colnum="31" colname="b37" align="center" /> + <colspec colnum="32" colname="b36" align="center" /> + <colspec colnum="33" colname="b35" align="center" /> + <colspec colnum="34" colname="b34" align="center" /> + <colspec colnum="35" colname="b33" align="center" /> + <colspec colnum="36" colname="b32" align="center" /> + <colspec colnum="37" colname="b31" align="center" /> + <colspec colnum="38" colname="b30" align="center" /> + + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <spanspec namest="b17" nameend="b10" spanname="b1" /> + <spanspec namest="b27" nameend="b20" spanname="b2" /> + <spanspec namest="b37" nameend="b30" spanname="b3" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry> </entry> + <entry spanname="b0">Byte 0 in memory</entry> + <entry spanname="b1">Byte 1</entry> + <entry spanname="b2">Byte 2</entry> + <entry spanname="b3">Byte 3</entry> + </row> + <row> + <entry> </entry> + <entry> </entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row><!-- id="V4L2-PIX-FMT-RGB332" --> + <entry><constant>V4L2_PIX_FMT_RGB332</constant></entry> + <entry>'RGB1'</entry> + <entry></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB444" --> + <entry><constant>V4L2_PIX_FMT_RGB444</constant></entry> + <entry>'R444'</entry> + <entry></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB555" --> + <entry><constant>V4L2_PIX_FMT_RGB555</constant></entry> + <entry>'RGBO'</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>a</entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB565" --> + <entry><constant>V4L2_PIX_FMT_RGB565</constant></entry> + <entry>'RGBP'</entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB555X" --> + <entry><constant>V4L2_PIX_FMT_RGB555X</constant></entry> + <entry>'RGBQ'</entry> + <entry></entry> + <entry>a</entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB565X" --> + <entry><constant>V4L2_PIX_FMT_RGB565X</constant></entry> + <entry>'RGBR'</entry> + <entry></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-BGR24" --> + <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry> + <entry>'BGR3'</entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB24" --> + <entry><constant>V4L2_PIX_FMT_RGB24</constant></entry> + <entry>'RGB3'</entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-BGR32" --> + <entry><constant>V4L2_PIX_FMT_BGR32</constant></entry> + <entry>'BGR4'</entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + </row> + <row><!-- id="V4L2-PIX-FMT-RGB32" --> + <entry><constant>V4L2_PIX_FMT_RGB32</constant></entry> + <entry>'RGB4'</entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry></entry> + <entry>r<subscript>7</subscript></entry> + <entry>r<subscript>6</subscript></entry> + <entry>r<subscript>5</subscript></entry> + <entry>r<subscript>4</subscript></entry> + <entry>r<subscript>3</subscript></entry> + <entry>r<subscript>2</subscript></entry> + <entry>r<subscript>1</subscript></entry> + <entry>r<subscript>0</subscript></entry> + <entry></entry> + <entry>g<subscript>7</subscript></entry> + <entry>g<subscript>6</subscript></entry> + <entry>g<subscript>5</subscript></entry> + <entry>g<subscript>4</subscript></entry> + <entry>g<subscript>3</subscript></entry> + <entry>g<subscript>2</subscript></entry> + <entry>g<subscript>1</subscript></entry> + <entry>g<subscript>0</subscript></entry> + <entry></entry> + <entry>b<subscript>7</subscript></entry> + <entry>b<subscript>6</subscript></entry> + <entry>b<subscript>5</subscript></entry> + <entry>b<subscript>4</subscript></entry> + <entry>b<subscript>3</subscript></entry> + <entry>b<subscript>2</subscript></entry> + <entry>b<subscript>1</subscript></entry> + <entry>b<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + + <para>A test utility to determine which RGB formats a driver +actually supports is available from the LinuxTV v4l-dvb repository. +See &v4l-dvb; for access instructions.</para> + + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-packed-yuv.xml b/Documentation/DocBook/v4l/pixfmt-packed-yuv.xml new file mode 100644 index 0000000..3cab5d0 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-packed-yuv.xml @@ -0,0 +1,244 @@ +<refentry id="packed-yuv"> + <refmeta> + <refentrytitle>Packed YUV formats</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname>Packed YUV formats</refname> + <refpurpose>Packed YUV formats</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>Similar to the packed RGB formats these formats store +the Y, Cb and Cr component of each pixel in one 16 or 32 bit +word.</para> + + <table pgwide="1" frame="none"> + <title>Packed YUV Image Formats</title> + <tgroup cols="37" align="center"> + <colspec colname="id" align="left" /> + <colspec colname="fourcc" /> + <colspec colname="bit" /> + + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + + <colspec colnum="13" colname="b17" align="center" /> + <colspec colnum="14" colname="b16" align="center" /> + <colspec colnum="15" colname="b15" align="center" /> + <colspec colnum="16" colname="b14" align="center" /> + <colspec colnum="17" colname="b13" align="center" /> + <colspec colnum="18" colname="b12" align="center" /> + <colspec colnum="19" colname="b11" align="center" /> + <colspec colnum="20" colname="b10" align="center" /> + + <colspec colnum="22" colname="b27" align="center" /> + <colspec colnum="23" colname="b26" align="center" /> + <colspec colnum="24" colname="b25" align="center" /> + <colspec colnum="25" colname="b24" align="center" /> + <colspec colnum="26" colname="b23" align="center" /> + <colspec colnum="27" colname="b22" align="center" /> + <colspec colnum="28" colname="b21" align="center" /> + <colspec colnum="29" colname="b20" align="center" /> + + <colspec colnum="31" colname="b37" align="center" /> + <colspec colnum="32" colname="b36" align="center" /> + <colspec colnum="33" colname="b35" align="center" /> + <colspec colnum="34" colname="b34" align="center" /> + <colspec colnum="35" colname="b33" align="center" /> + <colspec colnum="36" colname="b32" align="center" /> + <colspec colnum="37" colname="b31" align="center" /> + <colspec colnum="38" colname="b30" align="center" /> + + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <spanspec namest="b17" nameend="b10" spanname="b1" /> + <spanspec namest="b27" nameend="b20" spanname="b2" /> + <spanspec namest="b37" nameend="b30" spanname="b3" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry> </entry> + <entry spanname="b0">Byte 0 in memory</entry> + <entry spanname="b1">Byte 1</entry> + <entry spanname="b2">Byte 2</entry> + <entry spanname="b3">Byte 3</entry> + </row> + <row> + <entry> </entry> + <entry> </entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + <entry> </entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-YUV444"> + <entry><constant>V4L2_PIX_FMT_YUV444</constant></entry> + <entry>'Y444'</entry> + <entry></entry> + <entry>Cb<subscript>3</subscript></entry> + <entry>Cb<subscript>2</subscript></entry> + <entry>Cb<subscript>1</subscript></entry> + <entry>Cb<subscript>0</subscript></entry> + <entry>Cr<subscript>3</subscript></entry> + <entry>Cr<subscript>2</subscript></entry> + <entry>Cr<subscript>1</subscript></entry> + <entry>Cr<subscript>0</subscript></entry> + <entry></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry>Y'<subscript>3</subscript></entry> + <entry>Y'<subscript>2</subscript></entry> + <entry>Y'<subscript>1</subscript></entry> + <entry>Y'<subscript>0</subscript></entry> + </row> + + <row id="V4L2-PIX-FMT-YUV555"> + <entry><constant>V4L2_PIX_FMT_YUV555</constant></entry> + <entry>'YUVO'</entry> + <entry></entry> + <entry>Cb<subscript>2</subscript></entry> + <entry>Cb<subscript>1</subscript></entry> + <entry>Cb<subscript>0</subscript></entry> + <entry>Cr<subscript>4</subscript></entry> + <entry>Cr<subscript>3</subscript></entry> + <entry>Cr<subscript>2</subscript></entry> + <entry>Cr<subscript>1</subscript></entry> + <entry>Cr<subscript>0</subscript></entry> + <entry></entry> + <entry>a</entry> + <entry>Y'<subscript>4</subscript></entry> + <entry>Y'<subscript>3</subscript></entry> + <entry>Y'<subscript>2</subscript></entry> + <entry>Y'<subscript>1</subscript></entry> + <entry>Y'<subscript>0</subscript></entry> + <entry>Cb<subscript>4</subscript></entry> + <entry>Cb<subscript>3</subscript></entry> + </row> + + <row id="V4L2-PIX-FMT-YUV565"> + <entry><constant>V4L2_PIX_FMT_YUV565</constant></entry> + <entry>'YUVP'</entry> + <entry></entry> + <entry>Cb<subscript>2</subscript></entry> + <entry>Cb<subscript>1</subscript></entry> + <entry>Cb<subscript>0</subscript></entry> + <entry>Cr<subscript>4</subscript></entry> + <entry>Cr<subscript>3</subscript></entry> + <entry>Cr<subscript>2</subscript></entry> + <entry>Cr<subscript>1</subscript></entry> + <entry>Cr<subscript>0</subscript></entry> + <entry></entry> + <entry>Y'<subscript>4</subscript></entry> + <entry>Y'<subscript>3</subscript></entry> + <entry>Y'<subscript>2</subscript></entry> + <entry>Y'<subscript>1</subscript></entry> + <entry>Y'<subscript>0</subscript></entry> + <entry>Cb<subscript>5</subscript></entry> + <entry>Cb<subscript>4</subscript></entry> + <entry>Cb<subscript>3</subscript></entry> + </row> + + <row id="V4L2-PIX-FMT-YUV32"> + <entry><constant>V4L2_PIX_FMT_YUV32</constant></entry> + <entry>'YUV4'</entry> + <entry></entry> + <entry>a<subscript>7</subscript></entry> + <entry>a<subscript>6</subscript></entry> + <entry>a<subscript>5</subscript></entry> + <entry>a<subscript>4</subscript></entry> + <entry>a<subscript>3</subscript></entry> + <entry>a<subscript>2</subscript></entry> + <entry>a<subscript>1</subscript></entry> + <entry>a<subscript>0</subscript></entry> + <entry></entry> + <entry>Y'<subscript>7</subscript></entry> + <entry>Y'<subscript>6</subscript></entry> + <entry>Y'<subscript>5</subscript></entry> + <entry>Y'<subscript>4</subscript></entry> + <entry>Y'<subscript>3</subscript></entry> + <entry>Y'<subscript>2</subscript></entry> + <entry>Y'<subscript>1</subscript></entry> + <entry>Y'<subscript>0</subscript></entry> + <entry></entry> + <entry>Cb<subscript>7</subscript></entry> + <entry>Cb<subscript>6</subscript></entry> + <entry>Cb<subscript>5</subscript></entry> + <entry>Cb<subscript>4</subscript></entry> + <entry>Cb<subscript>3</subscript></entry> + <entry>Cb<subscript>2</subscript></entry> + <entry>Cb<subscript>1</subscript></entry> + <entry>Cb<subscript>0</subscript></entry> + <entry></entry> + <entry>Cr<subscript>7</subscript></entry> + <entry>Cr<subscript>6</subscript></entry> + <entry>Cr<subscript>5</subscript></entry> + <entry>Cr<subscript>4</subscript></entry> + <entry>Cr<subscript>3</subscript></entry> + <entry>Cr<subscript>2</subscript></entry> + <entry>Cr<subscript>1</subscript></entry> + <entry>Cr<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + + <para>Bit 7 is the most significant bit. The value of a = alpha +bits is undefined when reading from the driver, ignored when writing +to the driver, except when alpha blending has been negotiated for a +<link linkend="overlay">Video Overlay</link> or <link +linkend="osd">Video Output Overlay</link>.</para> + + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-sbggr16.xml b/Documentation/DocBook/v4l/pixfmt-sbggr16.xml new file mode 100644 index 0000000..519a9ef --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-sbggr16.xml @@ -0,0 +1,91 @@ +<refentry id="V4L2-PIX-FMT-SBGGR16"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SBGGR16 ('BYR2')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SBGGR16</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This format is similar to <link +linkend="V4L2-PIX-FMT-SBGGR8"> +<constant>V4L2_PIX_FMT_SBGGR8</constant></link>, except each pixel has +a depth of 16 bits. The least significant byte is stored at lower +memory addresses (little-endian). Note the actual sampling precision +may be lower than 16 bits, for example 10 bits per pixel with values +in range 0 to 1023.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SBGGR16</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>B<subscript>00low</subscript></entry> + <entry>B<subscript>00high</subscript></entry> + <entry>G<subscript>01low</subscript></entry> + <entry>G<subscript>01high</subscript></entry> + <entry>B<subscript>02low</subscript></entry> + <entry>B<subscript>02high</subscript></entry> + <entry>G<subscript>03low</subscript></entry> + <entry>G<subscript>03high</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>G<subscript>10low</subscript></entry> + <entry>G<subscript>10high</subscript></entry> + <entry>R<subscript>11low</subscript></entry> + <entry>R<subscript>11high</subscript></entry> + <entry>G<subscript>12low</subscript></entry> + <entry>G<subscript>12high</subscript></entry> + <entry>R<subscript>13low</subscript></entry> + <entry>R<subscript>13high</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>B<subscript>20low</subscript></entry> + <entry>B<subscript>20high</subscript></entry> + <entry>G<subscript>21low</subscript></entry> + <entry>G<subscript>21high</subscript></entry> + <entry>B<subscript>22low</subscript></entry> + <entry>B<subscript>22high</subscript></entry> + <entry>G<subscript>23low</subscript></entry> + <entry>G<subscript>23high</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>G<subscript>30low</subscript></entry> + <entry>G<subscript>30high</subscript></entry> + <entry>R<subscript>31low</subscript></entry> + <entry>R<subscript>31high</subscript></entry> + <entry>G<subscript>32low</subscript></entry> + <entry>G<subscript>32high</subscript></entry> + <entry>R<subscript>33low</subscript></entry> + <entry>R<subscript>33high</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-sbggr8.xml b/Documentation/DocBook/v4l/pixfmt-sbggr8.xml new file mode 100644 index 0000000..5fe84ec --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-sbggr8.xml @@ -0,0 +1,75 @@ + <refentry id="V4L2-PIX-FMT-SBGGR8"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SBGGR8 ('BA81')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SBGGR8</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a blue and green value, the second row of a green and +red value. This scheme repeats to the right and down for every two +columns and rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SBGGR8</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>B<subscript>00</subscript></entry> + <entry>G<subscript>01</subscript></entry> + <entry>B<subscript>02</subscript></entry> + <entry>G<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>G<subscript>10</subscript></entry> + <entry>R<subscript>11</subscript></entry> + <entry>G<subscript>12</subscript></entry> + <entry>R<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>B<subscript>20</subscript></entry> + <entry>G<subscript>21</subscript></entry> + <entry>B<subscript>22</subscript></entry> + <entry>G<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>G<subscript>30</subscript></entry> + <entry>R<subscript>31</subscript></entry> + <entry>G<subscript>32</subscript></entry> + <entry>R<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-sgbrg8.xml b/Documentation/DocBook/v4l/pixfmt-sgbrg8.xml new file mode 100644 index 0000000..d67a472 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-sgbrg8.xml @@ -0,0 +1,75 @@ + <refentry id="V4L2-PIX-FMT-SGBRG8"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SGBRG8 ('GBRG')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SGBRG8</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a green and blue value, the second row of a red and +green value. This scheme repeats to the right and down for every two +columns and rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SGBRG8</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>G<subscript>00</subscript></entry> + <entry>B<subscript>01</subscript></entry> + <entry>G<subscript>02</subscript></entry> + <entry>B<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>R<subscript>10</subscript></entry> + <entry>G<subscript>11</subscript></entry> + <entry>R<subscript>12</subscript></entry> + <entry>G<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>G<subscript>20</subscript></entry> + <entry>B<subscript>21</subscript></entry> + <entry>G<subscript>22</subscript></entry> + <entry>B<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>R<subscript>30</subscript></entry> + <entry>G<subscript>31</subscript></entry> + <entry>R<subscript>32</subscript></entry> + <entry>G<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-sgrbg8.xml b/Documentation/DocBook/v4l/pixfmt-sgrbg8.xml new file mode 100644 index 0000000..0cdf13b --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-sgrbg8.xml @@ -0,0 +1,75 @@ + <refentry id="V4L2-PIX-FMT-SGRBG8"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_SGRBG8 ('GRBG')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_SGRBG8</constant></refname> + <refpurpose>Bayer RGB format</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is commonly the native format of digital cameras, +reflecting the arrangement of sensors on the CCD device. Only one red, +green or blue value is given for each pixel. Missing components must +be interpolated from neighbouring pixels. From left to right the first +row consists of a green and blue value, the second row of a red and +green value. This scheme repeats to the right and down for every two +columns and rows.</para> + + <example> + <title><constant>V4L2_PIX_FMT_SGRBG8</constant> 4 × +4 pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>G<subscript>00</subscript></entry> + <entry>R<subscript>01</subscript></entry> + <entry>G<subscript>02</subscript></entry> + <entry>R<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>R<subscript>10</subscript></entry> + <entry>B<subscript>11</subscript></entry> + <entry>R<subscript>12</subscript></entry> + <entry>B<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>G<subscript>20</subscript></entry> + <entry>R<subscript>21</subscript></entry> + <entry>G<subscript>22</subscript></entry> + <entry>R<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>R<subscript>30</subscript></entry> + <entry>B<subscript>31</subscript></entry> + <entry>R<subscript>32</subscript></entry> + <entry>B<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-uyvy.xml b/Documentation/DocBook/v4l/pixfmt-uyvy.xml new file mode 100644 index 0000000..816c8d4 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-uyvy.xml @@ -0,0 +1,128 @@ + <refentry id="V4L2-PIX-FMT-UYVY"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_UYVY ('UYVY')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_UYVY</constant></refname> + <refpurpose>Variation of +<constant>V4L2_PIX_FMT_YUYV</constant> with different order of samples +in memory</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component.</para> + + <example> + <title><constant>V4L2_PIX_FMT_UYVY</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-vyuy.xml b/Documentation/DocBook/v4l/pixfmt-vyuy.xml new file mode 100644 index 0000000..61f12a5 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-vyuy.xml @@ -0,0 +1,128 @@ + <refentry id="V4L2-PIX-FMT-VYUY"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_VYUY ('VYUY')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_VYUY</constant></refname> + <refpurpose>Variation of +<constant>V4L2_PIX_FMT_YUYV</constant> with different order of samples +in memory</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component.</para> + + <example> + <title><constant>V4L2_PIX_FMT_VYUY</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-y16.xml b/Documentation/DocBook/v4l/pixfmt-y16.xml new file mode 100644 index 0000000..d584040 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-y16.xml @@ -0,0 +1,89 @@ +<refentry id="V4L2-PIX-FMT-Y16"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_Y16 ('Y16 ')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_Y16</constant></refname> + <refpurpose>Grey-scale image</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This is a grey-scale image with a depth of 16 bits per +pixel. The least significant byte is stored at lower memory addresses +(little-endian). Note the actual sampling precision may be lower than +16 bits, for example 10 bits per pixel with values in range 0 to +1023.</para> + + <example> + <title><constant>V4L2_PIX_FMT_Y16</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00low</subscript></entry> + <entry>Y'<subscript>00high</subscript></entry> + <entry>Y'<subscript>01low</subscript></entry> + <entry>Y'<subscript>01high</subscript></entry> + <entry>Y'<subscript>02low</subscript></entry> + <entry>Y'<subscript>02high</subscript></entry> + <entry>Y'<subscript>03low</subscript></entry> + <entry>Y'<subscript>03high</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>10low</subscript></entry> + <entry>Y'<subscript>10high</subscript></entry> + <entry>Y'<subscript>11low</subscript></entry> + <entry>Y'<subscript>11high</subscript></entry> + <entry>Y'<subscript>12low</subscript></entry> + <entry>Y'<subscript>12high</subscript></entry> + <entry>Y'<subscript>13low</subscript></entry> + <entry>Y'<subscript>13high</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20low</subscript></entry> + <entry>Y'<subscript>20high</subscript></entry> + <entry>Y'<subscript>21low</subscript></entry> + <entry>Y'<subscript>21high</subscript></entry> + <entry>Y'<subscript>22low</subscript></entry> + <entry>Y'<subscript>22high</subscript></entry> + <entry>Y'<subscript>23low</subscript></entry> + <entry>Y'<subscript>23high</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Y'<subscript>30low</subscript></entry> + <entry>Y'<subscript>30high</subscript></entry> + <entry>Y'<subscript>31low</subscript></entry> + <entry>Y'<subscript>31high</subscript></entry> + <entry>Y'<subscript>32low</subscript></entry> + <entry>Y'<subscript>32high</subscript></entry> + <entry>Y'<subscript>33low</subscript></entry> + <entry>Y'<subscript>33high</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> +</refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-y41p.xml b/Documentation/DocBook/v4l/pixfmt-y41p.xml new file mode 100644 index 0000000..73c8536 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-y41p.xml @@ -0,0 +1,157 @@ + <refentry id="V4L2-PIX-FMT-Y41P"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_Y41P ('Y41P')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_Y41P</constant></refname> + <refpurpose>Format with ¼ horizontal chroma +resolution, also known as YUV 4:1:1</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each 12 bytes is eight pixels. In the +twelve bytes are two CbCr pairs and eight Y's. The first CbCr pair +goes with the first four Y's, and the second CbCr pair goes with the +other four Y's. The Cb and Cr components have one fourth the +horizontal resolution of the Y component.</para> + + <para>Do not confuse this format with <link +linkend="V4L2-PIX-FMT-YUV411P"><constant>V4L2_PIX_FMT_YUV411P</constant></link>. +Y41P is derived from "YUV 4:1:1 <emphasis>packed</emphasis>", while +YUV411P stands for "YUV 4:1:1 <emphasis>planar</emphasis>".</para> + + <example> + <title><constant>V4L2_PIX_FMT_Y41P</constant> 8 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="13" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + <entry>Y'<subscript>04</subscript></entry> + <entry>Y'<subscript>05</subscript></entry> + <entry>Y'<subscript>06</subscript></entry> + <entry>Y'<subscript>07</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + <entry>Y'<subscript>14</subscript></entry> + <entry>Y'<subscript>15</subscript></entry> + <entry>Y'<subscript>16</subscript></entry> + <entry>Y'<subscript>17</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + <entry>Y'<subscript>24</subscript></entry> + <entry>Y'<subscript>25</subscript></entry> + <entry>Y'<subscript>26</subscript></entry> + <entry>Y'<subscript>27</subscript></entry> + </row> + <row> + <entry>start + 36:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + <entry>Y'<subscript>34</subscript></entry> + <entry>Y'<subscript>35</subscript></entry> + <entry>Y'<subscript>36</subscript></entry> + <entry>Y'<subscript>37</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable></para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="15" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry><entry></entry> + <entry>4</entry><entry></entry><entry>5</entry><entry></entry> + <entry>6</entry><entry></entry><entry>7</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-yuv410.xml b/Documentation/DocBook/v4l/pixfmt-yuv410.xml new file mode 100644 index 0000000..8eb4a19 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-yuv410.xml @@ -0,0 +1,141 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YVU410 ('YVU9'), V4L2_PIX_FMT_YUV410 ('YUV9')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-YVU410"><constant>V4L2_PIX_FMT_YVU410</constant></refname> + <refname id="V4L2-PIX-FMT-YUV410"><constant>V4L2_PIX_FMT_YUV410</constant></refname> + <refpurpose>Planar formats with ¼ horizontal and +vertical chroma resolution, also known as YUV 4:1:0</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are planar formats, as opposed to a packed format. +The three components are separated into three sub-images or planes. +The Y plane is first. The Y plane has one byte per pixel. For +<constant>V4L2_PIX_FMT_YVU410</constant>, the Cr plane immediately +follows the Y plane in memory. The Cr plane is ¼ the width and +¼ the height of the Y plane (and of the image). Each Cr belongs +to 16 pixels, a four-by-four square of the image. Following the Cr +plane is the Cb plane, just like the Cr plane. +<constant>V4L2_PIX_FMT_YUV410</constant> is the same, except the Cb +plane comes first, then the Cr plane.</para> + + <para>If the Y plane has pad bytes after each row, then the Cr +and Cb planes have ¼ as many pad bytes after their rows. In +other words, four Cx rows (including padding) are exactly as long as +one Y row (including padding).</para> + + <example> + <title><constant>V4L2_PIX_FMT_YVU410</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cr<subscript>00</subscript></entry> + </row> + <row> + <entry>start + 17:</entry> + <entry>Cb<subscript>00</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry></entry><entry></entry><entry>C</entry> + <entry></entry><entry></entry><entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-yuv411p.xml b/Documentation/DocBook/v4l/pixfmt-yuv411p.xml new file mode 100644 index 0000000..00e0960 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-yuv411p.xml @@ -0,0 +1,155 @@ + <refentry id="V4L2-PIX-FMT-YUV411P"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YUV411P ('411P')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_YUV411P</constant></refname> + <refpurpose>Format with ¼ horizontal chroma resolution, +also known as YUV 4:1:1. Planar layout as opposed to +<constant>V4L2_PIX_FMT_Y41P</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This format is not commonly used. This is a planar +format similar to the 4:2:2 planar format except with half as many +chroma. The three components are separated into three sub-images or +planes. The Y plane is first. The Y plane has one byte per pixel. The +Cb plane immediately follows the Y plane in memory. The Cb plane is +¼ the width of the Y plane (and of the image). Each Cb belongs +to 4 pixels all on the same row. For example, +Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>, +Y'<subscript>01</subscript>, Y'<subscript>02</subscript> and +Y'<subscript>03</subscript>. Following the Cb plane is the Cr plane, +just like the Cb plane.</para> + + <para>If the Y plane has pad bytes after each row, then the Cr +and Cb planes have ¼ as many pad bytes after their rows. In +other words, four C x rows (including padding) is exactly as long as +one Y row (including padding).</para> + + <example> + <title><constant>V4L2_PIX_FMT_YUV411P</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + </row> + <row> + <entry>start + 17:</entry> + <entry>Cb<subscript>10</subscript></entry> + </row> + <row> + <entry>start + 18:</entry> + <entry>Cb<subscript>20</subscript></entry> + </row> + <row> + <entry>start + 19:</entry> + <entry>Cb<subscript>30</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cr<subscript>00</subscript></entry> + </row> + <row> + <entry>start + 21:</entry> + <entry>Cr<subscript>10</subscript></entry> + </row> + <row> + <entry>start + 22:</entry> + <entry>Cr<subscript>20</subscript></entry> + </row> + <row> + <entry>start + 23:</entry> + <entry>Cr<subscript>30</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-yuv420.xml b/Documentation/DocBook/v4l/pixfmt-yuv420.xml new file mode 100644 index 0000000..42d7de5 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-yuv420.xml @@ -0,0 +1,157 @@ + <refentry> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YVU420 ('YV12'), V4L2_PIX_FMT_YUV420 ('YU12')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname id="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></refname> + <refname id="V4L2-PIX-FMT-YUV420"><constant>V4L2_PIX_FMT_YUV420</constant></refname> + <refpurpose>Planar formats with ½ horizontal and +vertical chroma resolution, also known as YUV 4:2:0</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>These are planar formats, as opposed to a packed format. +The three components are separated into three sub- images or planes. +The Y plane is first. The Y plane has one byte per pixel. For +<constant>V4L2_PIX_FMT_YVU420</constant>, the Cr plane immediately +follows the Y plane in memory. The Cr plane is half the width and half +the height of the Y plane (and of the image). Each Cr belongs to four +pixels, a two-by-two square of the image. For example, +Cr<subscript>0</subscript> belongs to Y'<subscript>00</subscript>, +Y'<subscript>01</subscript>, Y'<subscript>10</subscript>, and +Y'<subscript>11</subscript>. Following the Cr plane is the Cb plane, +just like the Cr plane. <constant>V4L2_PIX_FMT_YUV420</constant> is +the same except the Cb plane comes first, then the Cr plane.</para> + + <para>If the Y plane has pad bytes after each row, then the Cr +and Cb planes have half as many pad bytes after their rows. In other +words, two Cx rows (including padding) is exactly as long as one Y row +(including padding).</para> + + <example> + <title><constant>V4L2_PIX_FMT_YVU420</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 18:</entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 22:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + <row> + <entry></entry> + <entry></entry><entry>C</entry><entry></entry><entry></entry> + <entry></entry><entry>C</entry><entry></entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry></entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-yuv422p.xml b/Documentation/DocBook/v4l/pixfmt-yuv422p.xml new file mode 100644 index 0000000..4348bd9 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-yuv422p.xml @@ -0,0 +1,161 @@ + <refentry id="V4L2-PIX-FMT-YUV422P"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YUV422P ('422P')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_YUV422P</constant></refname> + <refpurpose>Format with ½ horizontal chroma resolution, +also known as YUV 4:2:2. Planar layout as opposed to +<constant>V4L2_PIX_FMT_YUYV</constant></refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>This format is not commonly used. This is a planar +version of the YUYV format. The three components are separated into +three sub-images or planes. The Y plane is first. The Y plane has one +byte per pixel. The Cb plane immediately follows the Y plane in +memory. The Cb plane is half the width of the Y plane (and of the +image). Each Cb belongs to two pixels. For example, +Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>, +Y'<subscript>01</subscript>. Following the Cb plane is the Cr plane, +just like the Cb plane.</para> + + <para>If the Y plane has pad bytes after each row, then the Cr +and Cb planes have half as many pad bytes after their rows. In other +words, two Cx rows (including padding) is exactly as long as one Y row +(including padding).</para> + + <example> + <title><constant>V4L2_PIX_FMT_YUV422P</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="5" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + </row> + <row> + <entry>start + 4:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + </row> + <row> + <entry>start + 12:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 18:</entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 20:</entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 22:</entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 26:</entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 28:</entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 30:</entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-yuyv.xml b/Documentation/DocBook/v4l/pixfmt-yuyv.xml new file mode 100644 index 0000000..bdb2ffa --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-yuyv.xml @@ -0,0 +1,128 @@ + <refentry id="V4L2-PIX-FMT-YUYV"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YUYV ('YUYV')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_YUYV</constant></refname> + <refpurpose>Packed format with ½ horizontal chroma +resolution, also known as YUV 4:2:2</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y component. +<constant>V4L2_PIX_FMT_YUYV </constant> is known in the Windows +environment as YUY2.</para> + + <example> + <title><constant>V4L2_PIX_FMT_YUYV</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt-yvyu.xml b/Documentation/DocBook/v4l/pixfmt-yvyu.xml new file mode 100644 index 0000000..40d17ae --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-yvyu.xml @@ -0,0 +1,128 @@ + <refentry id="V4L2-PIX-FMT-YVYU"> + <refmeta> + <refentrytitle>V4L2_PIX_FMT_YVYU ('YVYU')</refentrytitle> + &manvol; + </refmeta> + <refnamediv> + <refname><constant>V4L2_PIX_FMT_YVYU</constant></refname> + <refpurpose>Variation of +<constant>V4L2_PIX_FMT_YUYV</constant> with different order of samples +in memory</refpurpose> + </refnamediv> + <refsect1> + <title>Description</title> + + <para>In this format each four bytes is two pixels. Each four +bytes is two Y's, a Cb and a Cr. Each Y goes to one of the pixels, and +the Cb and Cr belong to both pixels. As you can see, the Cr and Cb +components have half the horizontal resolution of the Y +component.</para> + + <example> + <title><constant>V4L2_PIX_FMT_YVYU</constant> 4 × 4 +pixel image</title> + + <formalpara> + <title>Byte Order.</title> + <para>Each cell is one byte. + <informaltable frame="none"> + <tgroup cols="9" align="center"> + <colspec align="left" colwidth="2*" /> + <tbody valign="top"> + <row> + <entry>start + 0:</entry> + <entry>Y'<subscript>00</subscript></entry> + <entry>Cr<subscript>00</subscript></entry> + <entry>Y'<subscript>01</subscript></entry> + <entry>Cb<subscript>00</subscript></entry> + <entry>Y'<subscript>02</subscript></entry> + <entry>Cr<subscript>01</subscript></entry> + <entry>Y'<subscript>03</subscript></entry> + <entry>Cb<subscript>01</subscript></entry> + </row> + <row> + <entry>start + 8:</entry> + <entry>Y'<subscript>10</subscript></entry> + <entry>Cr<subscript>10</subscript></entry> + <entry>Y'<subscript>11</subscript></entry> + <entry>Cb<subscript>10</subscript></entry> + <entry>Y'<subscript>12</subscript></entry> + <entry>Cr<subscript>11</subscript></entry> + <entry>Y'<subscript>13</subscript></entry> + <entry>Cb<subscript>11</subscript></entry> + </row> + <row> + <entry>start + 16:</entry> + <entry>Y'<subscript>20</subscript></entry> + <entry>Cr<subscript>20</subscript></entry> + <entry>Y'<subscript>21</subscript></entry> + <entry>Cb<subscript>20</subscript></entry> + <entry>Y'<subscript>22</subscript></entry> + <entry>Cr<subscript>21</subscript></entry> + <entry>Y'<subscript>23</subscript></entry> + <entry>Cb<subscript>21</subscript></entry> + </row> + <row> + <entry>start + 24:</entry> + <entry>Y'<subscript>30</subscript></entry> + <entry>Cr<subscript>30</subscript></entry> + <entry>Y'<subscript>31</subscript></entry> + <entry>Cb<subscript>30</subscript></entry> + <entry>Y'<subscript>32</subscript></entry> + <entry>Cr<subscript>31</subscript></entry> + <entry>Y'<subscript>33</subscript></entry> + <entry>Cb<subscript>31</subscript></entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + + <formalpara> + <title>Color Sample Location.</title> + <para> + <informaltable frame="none"> + <tgroup cols="7" align="center"> + <tbody valign="top"> + <row> + <entry></entry> + <entry>0</entry><entry></entry><entry>1</entry><entry></entry> + <entry>2</entry><entry></entry><entry>3</entry> + </row> + <row> + <entry>0</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>1</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>2</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + <row> + <entry>3</entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry> + <entry>Y</entry><entry>C</entry><entry>Y</entry> + </row> + </tbody> + </tgroup> + </informaltable> + </para> + </formalpara> + </example> + </refsect1> + </refentry> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "pixfmt.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/pixfmt.xml b/Documentation/DocBook/v4l/pixfmt.xml new file mode 100644 index 0000000..aaea55d --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt.xml @@ -0,0 +1,796 @@ + <title>Image Formats</title> + + <para>The V4L2 API was primarily designed for devices exchanging +image data with applications. The +<structname>v4l2_pix_format</structname> structure defines the format +and layout of an image in memory. Image formats are negotiated with +the &VIDIOC-S-FMT; ioctl. (The explanations here focus on video +capturing and output, for overlay frame buffer formats see also +&VIDIOC-G-FBUF;.)</para> + + <table pgwide="1" frame="none" id="v4l2-pix-format"> + <title>struct <structname>v4l2_pix_format</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Image width in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Image height in pixels.</entry> + </row> + <row> + <entry spanname="hspan">Applications set these fields to +request an image size, drivers return the closest possible values. In +case of planar formats the <structfield>width</structfield> and +<structfield>height</structfield> applies to the largest plane. To +avoid ambiguities drivers must return values rounded up to a multiple +of the scale factor of any smaller planes. For example when the image +format is YUV 4:2:0, <structfield>width</structfield> and +<structfield>height</structfield> must be multiples of two.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixelformat</structfield></entry> + <entry>The pixel format or type of compression, set by the +application. This is a little endian <link +linkend="v4l2-fourcc">four character code</link>. V4L2 defines +standard RGB formats in <xref linkend="rgb-formats" />, YUV formats in <xref +linkend="yuv-formats" />, and reserved codes in <xref +linkend="reserved-formats" /></entry> + </row> + <row> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry>Video images are typically interlaced. Applications +can request to capture or output only the top or bottom field, or both +fields interlaced or sequentially stored in one buffer or alternating +in separate buffers. Drivers return the actual field order selected. +For details see <xref linkend="field-order" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>bytesperline</structfield></entry> + <entry>Distance in bytes between the leftmost pixels in two +adjacent lines.</entry> + </row> + <row> + <entry spanname="hspan"><para>Both applications and drivers +can set this field to request padding bytes at the end of each line. +Drivers however may ignore the value requested by the application, +returning <structfield>width</structfield> times bytes per pixel or a +larger value required by the hardware. That implies applications can +just set this field to zero to get a reasonable +default.</para><para>Video hardware may access padding bytes, +therefore they must reside in accessible memory. Consider cases where +padding bytes after the last line of an image cross a system page +boundary. Input devices may write padding bytes, the value is +undefined. Output devices ignore the contents of padding +bytes.</para><para>When the image format is planar the +<structfield>bytesperline</structfield> value applies to the largest +plane and is divided by the same factor as the +<structfield>width</structfield> field for any smaller planes. For +example the Cb and Cr planes of a YUV 4:2:0 image have half as many +padding bytes following each line as the Y plane. To avoid ambiguities +drivers must return a <structfield>bytesperline</structfield> value +rounded up to a multiple of the scale factor.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>sizeimage</structfield></entry> + <entry>Size in bytes of the buffer to hold a complete image, +set by the driver. Usually this is +<structfield>bytesperline</structfield> times +<structfield>height</structfield>. When the image consists of variable +length compressed data this is the maximum number of bytes required to +hold an image.</entry> + </row> + <row> + <entry>&v4l2-colorspace;</entry> + <entry><structfield>colorspace</structfield></entry> + <entry>This information supplements the +<structfield>pixelformat</structfield> and must be set by the driver, +see <xref linkend="colorspaces" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>priv</structfield></entry> + <entry>Reserved for custom (driver defined) additional +information about formats. When not used drivers and applications must +set this field to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <section> + <title>Standard Image Formats</title> + + <para>In order to exchange images between drivers and +applications, it is necessary to have standard image data formats +which both sides will interpret the same way. V4L2 includes several +such formats, and this section is intended to be an unambiguous +specification of the standard image data formats in V4L2.</para> + + <para>V4L2 drivers are not limited to these formats, however. +Driver-specific formats are possible. In that case the application may +depend on a codec to convert images to one of the standard formats +when needed. But the data can still be stored and retrieved in the +proprietary format. For example, a device may support a proprietary +compressed format. Applications can still capture and save the data in +the compressed format, saving much disk space, and later use a codec +to convert the images to the X Windows screen format when the video is +to be displayed.</para> + + <para>Even so, ultimately, some standard formats are needed, so +the V4L2 specification would not be complete without well-defined +standard formats.</para> + + <para>The V4L2 standard formats are mainly uncompressed formats. The +pixels are always arranged in memory from left to right, and from top +to bottom. The first byte of data in the image buffer is always for +the leftmost pixel of the topmost row. Following that is the pixel +immediately to its right, and so on until the end of the top row of +pixels. Following the rightmost pixel of the row there may be zero or +more bytes of padding to guarantee that each row of pixel data has a +certain alignment. Following the pad bytes, if any, is data for the +leftmost pixel of the second row from the top, and so on. The last row +has just as many pad bytes after it as the other rows.</para> + + <para>In V4L2 each format has an identifier which looks like +<constant>PIX_FMT_XXX</constant>, defined in the <link +linkend="videodev">videodev.h</link> header file. These identifiers +represent <link linkend="v4l2-fourcc">four character codes</link> +which are also listed below, however they are not the same as those +used in the Windows world.</para> + </section> + + <section id="colorspaces"> + <title>Colorspaces</title> + + <para>[intro]</para> + + <!-- See proposal by Billy Biggs, video4linux-list@redhat.com +on 11 Oct 2002, subject: "Re: [V4L] Re: v4l2 api", and +http://vektor.theorem.ca/graphics/ycbcr/ and +http://www.inforamp.net/~poynton/notes/colour_and_gamma/index.html --> + + <para> + <variablelist> + <varlistentry> + <term>Gamma Correction</term> + <listitem> + <para>[to do]</para> + <para>E'<subscript>R</subscript> = f(R)</para> + <para>E'<subscript>G</subscript> = f(G)</para> + <para>E'<subscript>B</subscript> = f(B)</para> + </listitem> + </varlistentry> + <varlistentry> + <term>Construction of luminance and color-difference +signals</term> + <listitem> + <para>[to do]</para> + <para>E'<subscript>Y</subscript> = +Coeff<subscript>R</subscript> E'<subscript>R</subscript> ++ Coeff<subscript>G</subscript> E'<subscript>G</subscript> ++ Coeff<subscript>B</subscript> E'<subscript>B</subscript></para> + <para>(E'<subscript>R</subscript> - E'<subscript>Y</subscript>) = E'<subscript>R</subscript> +- Coeff<subscript>R</subscript> E'<subscript>R</subscript> +- Coeff<subscript>G</subscript> E'<subscript>G</subscript> +- Coeff<subscript>B</subscript> E'<subscript>B</subscript></para> + <para>(E'<subscript>B</subscript> - E'<subscript>Y</subscript>) = E'<subscript>B</subscript> +- Coeff<subscript>R</subscript> E'<subscript>R</subscript> +- Coeff<subscript>G</subscript> E'<subscript>G</subscript> +- Coeff<subscript>B</subscript> E'<subscript>B</subscript></para> + </listitem> + </varlistentry> + <varlistentry> + <term>Re-normalized color-difference signals</term> + <listitem> + <para>The color-difference signals are scaled back to unity +range [-0.5;+0.5]:</para> + <para>K<subscript>B</subscript> = 0.5 / (1 - Coeff<subscript>B</subscript>)</para> + <para>K<subscript>R</subscript> = 0.5 / (1 - Coeff<subscript>R</subscript>)</para> + <para>P<subscript>B</subscript> = +K<subscript>B</subscript> (E'<subscript>B</subscript> - E'<subscript>Y</subscript>) = + 0.5 (Coeff<subscript>R</subscript> / Coeff<subscript>B</subscript>) E'<subscript>R</subscript> ++ 0.5 (Coeff<subscript>G</subscript> / Coeff<subscript>B</subscript>) E'<subscript>G</subscript> ++ 0.5 E'<subscript>B</subscript></para> + <para>P<subscript>R</subscript> = +K<subscript>R</subscript> (E'<subscript>R</subscript> - E'<subscript>Y</subscript>) = + 0.5 E'<subscript>R</subscript> ++ 0.5 (Coeff<subscript>G</subscript> / Coeff<subscript>R</subscript>) E'<subscript>G</subscript> ++ 0.5 (Coeff<subscript>B</subscript> / Coeff<subscript>R</subscript>) E'<subscript>B</subscript></para> + </listitem> + </varlistentry> + <varlistentry> + <term>Quantization</term> + <listitem> + <para>[to do]</para> + <para>Y' = (Lum. Levels - 1) · E'<subscript>Y</subscript> + Lum. Offset</para> + <para>C<subscript>B</subscript> = (Chrom. Levels - 1) +· P<subscript>B</subscript> + Chrom. Offset</para> + <para>C<subscript>R</subscript> = (Chrom. Levels - 1) +· P<subscript>R</subscript> + Chrom. Offset</para> + <para>Rounding to the nearest integer and clamping to the range +[0;255] finally yields the digital color components Y'CbCr +stored in YUV images.</para> + </listitem> + </varlistentry> + </variablelist> + </para> + + <example> + <title>ITU-R Rec. BT.601 color conversion</title> + + <para>Forward Transformation</para> + + <programlisting> +int ER, EG, EB; /* gamma corrected RGB input [0;255] */ +int Y1, Cb, Cr; /* output [0;255] */ + +double r, g, b; /* temporaries */ +double y1, pb, pr; + +int +clamp (double x) +{ + int r = x; /* round to nearest */ + + if (r < 0) return 0; + else if (r > 255) return 255; + else return r; +} + +r = ER / 255.0; +g = EG / 255.0; +b = EB / 255.0; + +y1 = 0.299 * r + 0.587 * g + 0.114 * b; +pb = -0.169 * r - 0.331 * g + 0.5 * b; +pr = 0.5 * r - 0.419 * g - 0.081 * b; + +Y1 = clamp (219 * y1 + 16); +Cb = clamp (224 * pb + 128); +Cr = clamp (224 * pr + 128); + +/* or shorter */ + +y1 = 0.299 * ER + 0.587 * EG + 0.114 * EB; + +Y1 = clamp ( (219 / 255.0) * y1 + 16); +Cb = clamp (((224 / 255.0) / (2 - 2 * 0.114)) * (EB - y1) + 128); +Cr = clamp (((224 / 255.0) / (2 - 2 * 0.299)) * (ER - y1) + 128); + </programlisting> + + <para>Inverse Transformation</para> + + <programlisting> +int Y1, Cb, Cr; /* gamma pre-corrected input [0;255] */ +int ER, EG, EB; /* output [0;255] */ + +double r, g, b; /* temporaries */ +double y1, pb, pr; + +int +clamp (double x) +{ + int r = x; /* round to nearest */ + + if (r < 0) return 0; + else if (r > 255) return 255; + else return r; +} + +y1 = (255 / 219.0) * (Y1 - 16); +pb = (255 / 224.0) * (Cb - 128); +pr = (255 / 224.0) * (Cr - 128); + +r = 1.0 * y1 + 0 * pb + 1.402 * pr; +g = 1.0 * y1 - 0.344 * pb - 0.714 * pr; +b = 1.0 * y1 + 1.772 * pb + 0 * pr; + +ER = clamp (r * 255); /* [ok? one should prob. limit y1,pb,pr] */ +EG = clamp (g * 255); +EB = clamp (b * 255); + </programlisting> + </example> + + <table pgwide="1" id="v4l2-colorspace" orient="land"> + <title>enum v4l2_colorspace</title> + <tgroup cols="11" align="center"> + <colspec align="left" /> + <colspec align="center" /> + <colspec align="left" /> + <colspec colname="cr" /> + <colspec colname="cg" /> + <colspec colname="cb" /> + <colspec colname="wp" /> + <colspec colname="gc" /> + <colspec colname="lum" /> + <colspec colname="qy" /> + <colspec colname="qc" /> + <spanspec namest="cr" nameend="cb" spanname="chrom" /> + <spanspec namest="qy" nameend="qc" spanname="quant" /> + <spanspec namest="lum" nameend="qc" spanname="spam" /> + <thead> + <row> + <entry morerows="1">Identifier</entry> + <entry morerows="1">Value</entry> + <entry morerows="1">Description</entry> + <entry spanname="chrom">Chromaticities<footnote> + <para>The coordinates of the color primaries are +given in the CIE system (1931)</para> + </footnote></entry> + <entry morerows="1">White Point</entry> + <entry morerows="1">Gamma Correction</entry> + <entry morerows="1">Luminance E'<subscript>Y</subscript></entry> + <entry spanname="quant">Quantization</entry> + </row> + <row> + <entry>Red</entry> + <entry>Green</entry> + <entry>Blue</entry> + <entry>Y'</entry> + <entry>Cb, Cr</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_COLORSPACE_SMPTE170M</constant></entry> + <entry>1</entry> + <entry>NTSC/PAL according to <xref linkend="smpte170m" />, +<xref linkend="itu601" /></entry> + <entry>x = 0.630, y = 0.340</entry> + <entry>x = 0.310, y = 0.595</entry> + <entry>x = 0.155, y = 0.070</entry> + <entry>x = 0.3127, y = 0.3290, + Illuminant D<subscript>65</subscript></entry> + <entry>E' = 4.5 I for I ≤0.018, +1.099 I<superscript>0.45</superscript> - 0.099 for 0.018 < I</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_SMPTE240M</constant></entry> + <entry>2</entry> + <entry>1125-Line (US) HDTV, see <xref +linkend="smpte240m" /></entry> + <entry>x = 0.630, y = 0.340</entry> + <entry>x = 0.310, y = 0.595</entry> + <entry>x = 0.155, y = 0.070</entry> + <entry>x = 0.3127, y = 0.3290, + Illuminant D<subscript>65</subscript></entry> + <entry>E' = 4 I for I ≤0.0228, +1.1115 I<superscript>0.45</superscript> - 0.1115 for 0.0228 < I</entry> + <entry>0.212 E'<subscript>R</subscript> ++ 0.701 E'<subscript>G</subscript> ++ 0.087 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_REC709</constant></entry> + <entry>3</entry> + <entry>HDTV and modern devices, see <xref +linkend="itu709" /></entry> + <entry>x = 0.640, y = 0.330</entry> + <entry>x = 0.300, y = 0.600</entry> + <entry>x = 0.150, y = 0.060</entry> + <entry>x = 0.3127, y = 0.3290, + Illuminant D<subscript>65</subscript></entry> + <entry>E' = 4.5 I for I ≤0.018, +1.099 I<superscript>0.45</superscript> - 0.099 for 0.018 < I</entry> + <entry>0.2125 E'<subscript>R</subscript> ++ 0.7154 E'<subscript>G</subscript> ++ 0.0721 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_BT878</constant></entry> + <entry>4</entry> + <entry>Broken Bt878 extents<footnote> + <para>The ubiquitous Bt878 video capture chip +quantizes E'<subscript>Y</subscript> to 238 levels, yielding a range +of Y' = 16 … 253, unlike Rec. 601 Y' = 16 … +235. This is not a typo in the Bt878 documentation, it has been +implemented in silicon. The chroma extents are unclear.</para> + </footnote>, <xref linkend="itu601" /></entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry><emphasis>237</emphasis> E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128 (probably)</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_470_SYSTEM_M</constant></entry> + <entry>5</entry> + <entry>M/NTSC<footnote> + <para>No identifier exists for M/PAL which uses +the chromaticities of M/NTSC, the remaining parameters are equal to B and +G/PAL.</para> + </footnote> according to <xref linkend="itu470" />, <xref + linkend="itu601" /></entry> + <entry>x = 0.67, y = 0.33</entry> + <entry>x = 0.21, y = 0.71</entry> + <entry>x = 0.14, y = 0.08</entry> + <entry>x = 0.310, y = 0.316, Illuminant C</entry> + <entry>?</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant></entry> + <entry>6</entry> + <entry>625-line PAL and SECAM systems according to <xref +linkend="itu470" />, <xref linkend="itu601" /></entry> + <entry>x = 0.64, y = 0.33</entry> + <entry>x = 0.29, y = 0.60</entry> + <entry>x = 0.15, y = 0.06</entry> + <entry>x = 0.313, y = 0.329, +Illuminant D<subscript>65</subscript></entry> + <entry>?</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry>219 E'<subscript>Y</subscript> + 16</entry> + <entry>224 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_JPEG</constant></entry> + <entry>7</entry> + <entry>JPEG Y'CbCr, see <xref linkend="jfif" />, <xref linkend="itu601" /></entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>?</entry> + <entry>0.299 E'<subscript>R</subscript> ++ 0.587 E'<subscript>G</subscript> ++ 0.114 E'<subscript>B</subscript></entry> + <entry>256 E'<subscript>Y</subscript> + 16<footnote> + <para>Note JFIF quantizes +Y'P<subscript>B</subscript>P<subscript>R</subscript> in range [0;+1] and +[-0.5;+0.5] to <emphasis>257</emphasis> levels, however Y'CbCr signals +are still clamped to [0;255].</para> + </footnote></entry> + <entry>256 P<subscript>B,R</subscript> + 128</entry> + </row> + <row> + <entry><constant>V4L2_COLORSPACE_SRGB</constant></entry> + <entry>8</entry> + <entry>[?]</entry> + <entry>x = 0.640, y = 0.330</entry> + <entry>x = 0.300, y = 0.600</entry> + <entry>x = 0.150, y = 0.060</entry> + <entry>x = 0.3127, y = 0.3290, + Illuminant D<subscript>65</subscript></entry> + <entry>E' = 4.5 I for I ≤0.018, +1.099 I<superscript>0.45</superscript> - 0.099 for 0.018 < I</entry> + <entry spanname="spam">n/a</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section id="pixfmt-indexed"> + <title>Indexed Format</title> + + <para>In this format each pixel is represented by an 8 bit index +into a 256 entry ARGB palette. It is intended for <link +linkend="osd">Video Output Overlays</link> only. There are no ioctls to +access the palette, this must be done with ioctls of the Linux framebuffer API.</para> + + <table pgwide="0" frame="none"> + <title>Indexed Image Format</title> + <tgroup cols="37" align="center"> + <colspec colname="id" align="left" /> + <colspec colname="fourcc" /> + <colspec colname="bit" /> + + <colspec colnum="4" colname="b07" align="center" /> + <colspec colnum="5" colname="b06" align="center" /> + <colspec colnum="6" colname="b05" align="center" /> + <colspec colnum="7" colname="b04" align="center" /> + <colspec colnum="8" colname="b03" align="center" /> + <colspec colnum="9" colname="b02" align="center" /> + <colspec colnum="10" colname="b01" align="center" /> + <colspec colnum="11" colname="b00" align="center" /> + + <spanspec namest="b07" nameend="b00" spanname="b0" /> + <spanspec namest="b17" nameend="b10" spanname="b1" /> + <spanspec namest="b27" nameend="b20" spanname="b2" /> + <spanspec namest="b37" nameend="b30" spanname="b3" /> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry> </entry> + <entry spanname="b0">Byte 0</entry> + </row> + <row> + <entry> </entry> + <entry> </entry> + <entry>Bit</entry> + <entry>7</entry> + <entry>6</entry> + <entry>5</entry> + <entry>4</entry> + <entry>3</entry> + <entry>2</entry> + <entry>1</entry> + <entry>0</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-PAL8"> + <entry><constant>V4L2_PIX_FMT_PAL8</constant></entry> + <entry>'PAL8'</entry> + <entry></entry> + <entry>i<subscript>7</subscript></entry> + <entry>i<subscript>6</subscript></entry> + <entry>i<subscript>5</subscript></entry> + <entry>i<subscript>4</subscript></entry> + <entry>i<subscript>3</subscript></entry> + <entry>i<subscript>2</subscript></entry> + <entry>i<subscript>1</subscript></entry> + <entry>i<subscript>0</subscript></entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section id="pixfmt-rgb"> + <title>RGB Formats</title> + + &sub-packed-rgb; + &sub-sbggr8; + &sub-sgbrg8; + &sub-sgrbg8; + &sub-sbggr16; + </section> + + <section id="yuv-formats"> + <title>YUV Formats</title> + + <para>YUV is the format native to TV broadcast and composite video +signals. It separates the brightness information (Y) from the color +information (U and V or Cb and Cr). The color information consists of +red and blue <emphasis>color difference</emphasis> signals, this way +the green component can be reconstructed by subtracting from the +brightness component. See <xref linkend="colorspaces" /> for conversion +examples. YUV was chosen because early television would only transmit +brightness information. To add color in a way compatible with existing +receivers a new signal carrier was added to transmit the color +difference signals. Secondary in the YUV format the U and V components +usually have lower resolution than the Y component. This is an analog +video compression technique taking advantage of a property of the +human visual system, being more sensitive to brightness +information.</para> + + &sub-packed-yuv; + &sub-grey; + &sub-y16; + &sub-yuyv; + &sub-uyvy; + &sub-yvyu; + &sub-vyuy; + &sub-y41p; + &sub-yuv420; + &sub-yuv410; + &sub-yuv422p; + &sub-yuv411p; + &sub-nv12; + &sub-nv16; + </section> + + <section> + <title>Compressed Formats</title> + + <table pgwide="1" frame="none" id="compressed-formats"> + <title>Compressed Image Formats</title> + <tgroup cols="3" align="left"> + &cs-def; + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry>Details</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-JPEG"> + <entry><constant>V4L2_PIX_FMT_JPEG</constant></entry> + <entry>'JPEG'</entry> + <entry>TBD. See also &VIDIOC-G-JPEGCOMP;, + &VIDIOC-S-JPEGCOMP;.</entry> + </row> + <row id="V4L2-PIX-FMT-MPEG"> + <entry><constant>V4L2_PIX_FMT_MPEG</constant></entry> + <entry>'MPEG'</entry> + <entry>MPEG stream. The actual format is determined by +extended control <constant>V4L2_CID_MPEG_STREAM_TYPE</constant>, see +<xref linkend="mpeg-control-id" />.</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <section id="pixfmt-reserved"> + <title>Reserved Format Identifiers</title> + + <para>These formats are not defined by this specification, they +are just listed for reference and to avoid naming conflicts. If you +want to register your own format, send an e-mail to the linux-media mailing +list &v4l-ml; for inclusion in the <filename>videodev2.h</filename> +file. If you want to share your format with other developers add a +link to your documentation and send a copy to the linux-media mailing list +for inclusion in this section. If you think your format should be listed +in a standard format section please make a proposal on the linux-media mailing +list.</para> + + <table pgwide="1" frame="none" id="reserved-formats"> + <title>Reserved Image Formats</title> + <tgroup cols="3" align="left"> + &cs-def; + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + <entry>Details</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2-PIX-FMT-DV"> + <entry><constant>V4L2_PIX_FMT_DV</constant></entry> + <entry>'dvsd'</entry> + <entry>unknown</entry> + </row> + <row id="V4L2-PIX-FMT-ET61X251"> + <entry><constant>V4L2_PIX_FMT_ET61X251</constant></entry> + <entry>'E625'</entry> + <entry>Compressed format of the ET61X251 driver.</entry> + </row> + <row id="V4L2-PIX-FMT-HI240"> + <entry><constant>V4L2_PIX_FMT_HI240</constant></entry> + <entry>'HI24'</entry> + <entry><para>8 bit RGB format used by the BTTV driver.</para></entry> + </row> + <row id="V4L2-PIX-FMT-HM12"> + <entry><constant>V4L2_PIX_FMT_HM12</constant></entry> + <entry>'HM12'</entry> + <entry><para>YUV 4:2:0 format used by the +IVTV driver, <ulink url="http://www.ivtvdriver.org/"> +http://www.ivtvdriver.org/</ulink></para><para>The format is documented in the +kernel sources in the file <filename>Documentation/video4linux/cx2341x/README.hm12</filename> +</para></entry> + </row> + <row id="V4L2-PIX-FMT-SPCA501"> + <entry><constant>V4L2_PIX_FMT_SPCA501</constant></entry> + <entry>'S501'</entry> + <entry>YUYV per line used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SPCA505"> + <entry><constant>V4L2_PIX_FMT_SPCA505</constant></entry> + <entry>'S505'</entry> + <entry>YYUV per line used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SPCA508"> + <entry><constant>V4L2_PIX_FMT_SPCA508</constant></entry> + <entry>'S508'</entry> + <entry>YUVY per line used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SPCA561"> + <entry><constant>V4L2_PIX_FMT_SPCA561</constant></entry> + <entry>'S561'</entry> + <entry>Compressed GBRG Bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SGRBG10"> + <entry><constant>V4L2_PIX_FMT_SGRBG10</constant></entry> + <entry>'DA10'</entry> + <entry>10 bit raw Bayer, expanded to 16 bits.</entry> + </row> + <row id="V4L2-PIX-FMT-SGRBG10DPCM8"> + <entry><constant>V4L2_PIX_FMT_SGRBG10DPCM8</constant></entry> + <entry>'DB10'</entry> + <entry>10 bit raw Bayer DPCM compressed to 8 bits.</entry> + </row> + <row id="V4L2-PIX-FMT-PAC207"> + <entry><constant>V4L2_PIX_FMT_PAC207</constant></entry> + <entry>'P207'</entry> + <entry>Compressed BGGR Bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-MR97310A"> + <entry><constant>V4L2_PIX_FMT_MR97310A</constant></entry> + <entry>'M310'</entry> + <entry>Compressed BGGR Bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-OV511"> + <entry><constant>V4L2_PIX_FMT_OV511</constant></entry> + <entry>'O511'</entry> + <entry>OV511 JPEG format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-OV518"> + <entry><constant>V4L2_PIX_FMT_OV518</constant></entry> + <entry>'O518'</entry> + <entry>OV518 JPEG format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-PJPG"> + <entry><constant>V4L2_PIX_FMT_PJPG</constant></entry> + <entry>'PJPG'</entry> + <entry>Pixart 73xx JPEG format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SQ905C"> + <entry><constant>V4L2_PIX_FMT_SQ905C</constant></entry> + <entry>'905C'</entry> + <entry>Compressed RGGB bayer format used by the gspca driver.</entry> + </row> + <row id="V4L2-PIX-FMT-MJPEG"> + <entry><constant>V4L2_PIX_FMT_MJPEG</constant></entry> + <entry>'MJPG'</entry> + <entry>Compressed format used by the Zoran driver</entry> + </row> + <row id="V4L2-PIX-FMT-PWC1"> + <entry><constant>V4L2_PIX_FMT_PWC1</constant></entry> + <entry>'PWC1'</entry> + <entry>Compressed format of the PWC driver.</entry> + </row> + <row id="V4L2-PIX-FMT-PWC2"> + <entry><constant>V4L2_PIX_FMT_PWC2</constant></entry> + <entry>'PWC2'</entry> + <entry>Compressed format of the PWC driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SN9C10X"> + <entry><constant>V4L2_PIX_FMT_SN9C10X</constant></entry> + <entry>'S910'</entry> + <entry>Compressed format of the SN9C102 driver.</entry> + </row> + <row id="V4L2-PIX-FMT-SN9C20X-I420"> + <entry><constant>V4L2_PIX_FMT_SN9C20X_I420</constant></entry> + <entry>'S920'</entry> + <entry>YUV 4:2:0 format of the gspca sn9c20x driver.</entry> + </row> + <row id="V4L2-PIX-FMT-WNVA"> + <entry><constant>V4L2_PIX_FMT_WNVA</constant></entry> + <entry>'WNVA'</entry> + <entry><para>Used by the Winnov Videum driver, <ulink +url="http://www.thedirks.org/winnov/"> +http://www.thedirks.org/winnov/</ulink></para></entry> + </row> + <row id="V4L2-PIX-FMT-YYUV"> + <entry><constant>V4L2_PIX_FMT_YYUV</constant></entry> + <entry>'YYUV'</entry> + <entry>unknown</entry> + </row> + </tbody> + </tgroup> + </table> + </section> + + <!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: + --> diff --git a/Documentation/DocBook/v4l/remote_controllers.xml b/Documentation/DocBook/v4l/remote_controllers.xml new file mode 100644 index 0000000..eb66953 --- /dev/null +++ b/Documentation/DocBook/v4l/remote_controllers.xml @@ -0,0 +1,170 @@ +<title>Remote Controllers</title> +<section id="Remote_controllers_Intro"> +<title>Introduction</title> + +<para>Currently, most analog and digital devices have a Infrared input for remote controllers. Each manufacturer has their own type of control. It is not rare that the same manufacturer to ship different types of controls, depending on the device.</para> +<para>Unfortunately, during several years, there weren't any effort to uniform the IR keycodes under different boards. This resulted that the same IR keyname to be mapped completely different on different IR's. Due to that, V4L2 API now specifies a standard for mapping Media keys on IR.</para> +<para>This standard should be used by both V4L/DVB drivers and userspace applications</para> +<para>The modules register the remote as keyboard within the linux input layer. This means that the IR key strokes will look like normal keyboard key strokes (if CONFIG_INPUT_KEYBOARD is enabled). Using the event devices (CONFIG_INPUT_EVDEV) it is possible for applications to access the remote via /dev/input/event devices.</para> + +<table pgwide="1" frame="none" id="rc_standard_keymap"> +<title>IR default keymapping</title> +<tgroup cols="3"> +&cs-str; +<tbody valign="top"> +<row> +<entry>Key code</entry> +<entry>Meaning</entry> +<entry>Key examples on IR</entry> +</row> + +<row><entry><emphasis role="bold">Numeric keys</emphasis></entry></row> + +<row><entry><constant>KEY_0</constant></entry><entry>Keyboard digit 0</entry><entry>0</entry></row> +<row><entry><constant>KEY_1</constant></entry><entry>Keyboard digit 1</entry><entry>1</entry></row> +<row><entry><constant>KEY_2</constant></entry><entry>Keyboard digit 2</entry><entry>2</entry></row> +<row><entry><constant>KEY_3</constant></entry><entry>Keyboard digit 3</entry><entry>3</entry></row> +<row><entry><constant>KEY_4</constant></entry><entry>Keyboard digit 4</entry><entry>4</entry></row> +<row><entry><constant>KEY_5</constant></entry><entry>Keyboard digit 5</entry><entry>5</entry></row> +<row><entry><constant>KEY_6</constant></entry><entry>Keyboard digit 6</entry><entry>6</entry></row> +<row><entry><constant>KEY_7</constant></entry><entry>Keyboard digit 7</entry><entry>7</entry></row> +<row><entry><constant>KEY_8</constant></entry><entry>Keyboard digit 8</entry><entry>8</entry></row> +<row><entry><constant>KEY_9</constant></entry><entry>Keyboard digit 9</entry><entry>9</entry></row> + +<row><entry><emphasis role="bold">Movie play control</emphasis></entry></row> + +<row><entry><constant>KEY_FORWARD</constant></entry><entry>Instantly advance in time</entry><entry>>> / FORWARD</entry></row> +<row><entry><constant>KEY_BACK</constant></entry><entry>Instantly go back in time</entry><entry><<< / BACK</entry></row> +<row><entry><constant>KEY_FASTFORWARD</constant></entry><entry>Play movie faster</entry><entry>>>> / FORWARD</entry></row> +<row><entry><constant>KEY_REWIND</constant></entry><entry>Play movie back</entry><entry>REWIND / BACKWARD</entry></row> +<row><entry><constant>KEY_NEXT</constant></entry><entry>Select next chapter / sub-chapter / interval</entry><entry>NEXT / SKIP</entry></row> +<row><entry><constant>KEY_PREVIOUS</constant></entry><entry>Select previous chapter / sub-chapter / interval</entry><entry><< / PREV / PREVIOUS</entry></row> +<row><entry><constant>KEY_AGAIN</constant></entry><entry>Repeat the video or a video interval</entry><entry>REPEAT / LOOP / RECALL</entry></row> +<row><entry><constant>KEY_PAUSE</constant></entry><entry>Pause sroweam</entry><entry>PAUSE / FREEZE</entry></row> +<row><entry><constant>KEY_PLAY</constant></entry><entry>Play movie at the normal timeshift</entry><entry>NORMAL TIMESHIFT / LIVE / ></entry></row> +<row><entry><constant>KEY_PLAYPAUSE</constant></entry><entry>Alternate between play and pause</entry><entry>PLAY / PAUSE</entry></row> +<row><entry><constant>KEY_STOP</constant></entry><entry>Stop sroweam</entry><entry>STOP</entry></row> +<row><entry><constant>KEY_RECORD</constant></entry><entry>Start/stop recording sroweam</entry><entry>CAPTURE / REC / RECORD/PAUSE</entry></row> +<row><entry><constant>KEY_CAMERA</constant></entry><entry>Take a picture of the image</entry><entry>CAMERA ICON / CAPTURE / SNAPSHOT</entry></row> +<row><entry><constant>KEY_SHUFFLE</constant></entry><entry>Enable shuffle mode</entry><entry>SHUFFLE</entry></row> +<row><entry><constant>KEY_TIME</constant></entry><entry>Activate time shift mode</entry><entry>TIME SHIFT</entry></row> +<row><entry><constant>KEY_TITLE</constant></entry><entry>Allow changing the chapter</entry><entry>CHAPTER</entry></row> +<row><entry><constant>KEY_SUBTITLE</constant></entry><entry>Allow changing the subtitle</entry><entry>SUBTITLE</entry></row> + +<row><entry><emphasis role="bold">Image control</emphasis></entry></row> + +<row><entry><constant>KEY_BRIGHTNESSDOWN</constant></entry><entry>Decrease Brightness</entry><entry>BRIGHTNESS DECREASE</entry></row> +<row><entry><constant>KEY_BRIGHTNESSUP</constant></entry><entry>Increase Brightness</entry><entry>BRIGHTNESS INCREASE</entry></row> + +<row><entry><constant>KEY_ANGLE</constant></entry><entry>Switch video camera angle (on videos with more than one angle stored)</entry><entry>ANGLE / SWAP</entry></row> +<row><entry><constant>KEY_EPG</constant></entry><entry>Open the Elecrowonic Play Guide (EPG)</entry><entry>EPG / GUIDE</entry></row> +<row><entry><constant>KEY_TEXT</constant></entry><entry>Activate/change closed caption mode</entry><entry>CLOSED CAPTION/TELETEXT / DVD TEXT / TELETEXT / TTX</entry></row> + +<row><entry><emphasis role="bold">Audio control</emphasis></entry></row> + +<row><entry><constant>KEY_AUDIO</constant></entry><entry>Change audio source</entry><entry>AUDIO SOURCE / AUDIO / MUSIC</entry></row> +<row><entry><constant>KEY_MUTE</constant></entry><entry>Mute/unmute audio</entry><entry>MUTE / DEMUTE / UNMUTE</entry></row> +<row><entry><constant>KEY_VOLUMEDOWN</constant></entry><entry>Decrease volume</entry><entry>VOLUME- / VOLUME DOWN</entry></row> +<row><entry><constant>KEY_VOLUMEUP</constant></entry><entry>Increase volume</entry><entry>VOLUME+ / VOLUME UP</entry></row> +<row><entry><constant>KEY_MODE</constant></entry><entry>Change sound mode</entry><entry>MONO/STEREO</entry></row> +<row><entry><constant>KEY_LANGUAGE</constant></entry><entry>Select Language</entry><entry>1ST / 2ND LANGUAGE / DVD LANG / MTS/SAP / MTS SEL</entry></row> + +<row><entry><emphasis role="bold">Channel control</emphasis></entry></row> + +<row><entry><constant>KEY_CHANNEL</constant></entry><entry>Go to the next favorite channel</entry><entry>ALT / CHANNEL / CH SURFING / SURF / FAV</entry></row> +<row><entry><constant>KEY_CHANNELDOWN</constant></entry><entry>Decrease channel sequencially</entry><entry>CHANNEL - / CHANNEL DOWN / DOWN</entry></row> +<row><entry><constant>KEY_CHANNELUP</constant></entry><entry>Increase channel sequencially</entry><entry>CHANNEL + / CHANNEL UP / UP</entry></row> +<row><entry><constant>KEY_DIGITS</constant></entry><entry>Use more than one digit for channel</entry><entry>PLUS / 100/ 1xx / xxx / -/-- / Single Double Triple Digit</entry></row> +<row><entry><constant>KEY_SEARCH</constant></entry><entry>Start channel autoscan</entry><entry>SCAN / AUTOSCAN</entry></row> + +<row><entry><emphasis role="bold">Colored keys</emphasis></entry></row> + +<row><entry><constant>KEY_BLUE</constant></entry><entry>IR Blue key</entry><entry>BLUE</entry></row> +<row><entry><constant>KEY_GREEN</constant></entry><entry>IR Green Key</entry><entry>GREEN</entry></row> +<row><entry><constant>KEY_RED</constant></entry><entry>IR Red key</entry><entry>RED</entry></row> +<row><entry><constant>KEY_YELLOW</constant></entry><entry>IR Yellow key</entry><entry> YELLOW</entry></row> + +<row><entry><emphasis role="bold">Media selection</emphasis></entry></row> + +<row><entry><constant>KEY_CD</constant></entry><entry>Change input source to Compact Disc</entry><entry>CD</entry></row> +<row><entry><constant>KEY_DVD</constant></entry><entry>Change input to DVD</entry><entry>DVD / DVD MENU</entry></row> +<row><entry><constant>KEY_EJECTCLOSECD</constant></entry><entry>Open/close the CD/DVD player</entry><entry>-> ) / CLOSE / OPEN</entry></row> + +<row><entry><constant>KEY_MEDIA</constant></entry><entry>Turn on/off Media application</entry><entry>PC/TV / TURN ON/OFF APP</entry></row> +<row><entry><constant>KEY_PC</constant></entry><entry>Selects from TV to PC</entry><entry>PC</entry></row> +<row><entry><constant>KEY_RADIO</constant></entry><entry>Put into AM/FM radio mode</entry><entry>RADIO / TV/FM / TV/RADIO / FM / FM/RADIO</entry></row> +<row><entry><constant>KEY_TV</constant></entry><entry>Select tv mode</entry><entry>TV / LIVE TV</entry></row> +<row><entry><constant>KEY_TV2</constant></entry><entry>Select Cable mode</entry><entry>AIR/CBL</entry></row> +<row><entry><constant>KEY_VCR</constant></entry><entry>Select VCR mode</entry><entry>VCR MODE / DTR</entry></row> +<row><entry><constant>KEY_VIDEO</constant></entry><entry>Alternate between input modes</entry><entry>SOURCE / SELECT / DISPLAY / SWITCH INPUTS / VIDEO</entry></row> + +<row><entry><emphasis role="bold">Power control</emphasis></entry></row> + +<row><entry><constant>KEY_POWER</constant></entry><entry>Turn on/off computer</entry><entry>SYSTEM POWER / COMPUTER POWER</entry></row> +<row><entry><constant>KEY_POWER2</constant></entry><entry>Turn on/off application</entry><entry>TV ON/OFF / POWER</entry></row> +<row><entry><constant>KEY_SLEEP</constant></entry><entry>Activate sleep timer</entry><entry>SLEEP / SLEEP TIMER</entry></row> +<row><entry><constant>KEY_SUSPEND</constant></entry><entry>Put computer into suspend mode</entry><entry>STANDBY / SUSPEND</entry></row> + +<row><entry><emphasis role="bold">Window control</emphasis></entry></row> + +<row><entry><constant>KEY_CLEAR</constant></entry><entry>Stop sroweam and return to default input video/audio</entry><entry>CLEAR / RESET / BOSS KEY</entry></row> +<row><entry><constant>KEY_CYCLEWINDOWS</constant></entry><entry>Minimize windows and move to the next one</entry><entry>ALT-TAB / MINIMIZE / DESKTOP</entry></row> +<row><entry><constant>KEY_FAVORITES</constant></entry><entry>Open the favorites sroweam window</entry><entry>TV WALL / Favorites</entry></row> +<row><entry><constant>KEY_MENU</constant></entry><entry>Call application menu</entry><entry>2ND CONTROLS (USA: MENU) / DVD/MENU / SHOW/HIDE CTRL</entry></row> +<row><entry><constant>KEY_NEW</constant></entry><entry>Open/Close Picture in Picture</entry><entry>PIP</entry></row> +<row><entry><constant>KEY_OK</constant></entry><entry>Send a confirmation code to application</entry><entry>OK / ENTER / RETURN</entry></row> +<row><entry><constant>KEY_SCREEN</constant></entry><entry>Select screen aspect ratio</entry><entry>4:3 16:9 SELECT</entry></row> +<row><entry><constant>KEY_ZOOM</constant></entry><entry>Put device into zoom/full screen mode</entry><entry>ZOOM / FULL SCREEN / ZOOM+ / HIDE PANNEL / SWITCH</entry></row> + +<row><entry><emphasis role="bold">Navigation keys</emphasis></entry></row> + +<row><entry><constant>KEY_ESC</constant></entry><entry>Cancel current operation</entry><entry>CANCEL / BACK</entry></row> +<row><entry><constant>KEY_HELP</constant></entry><entry>Open a Help window</entry><entry>HELP</entry></row> +<row><entry><constant>KEY_HOMEPAGE</constant></entry><entry>Navigate to Homepage</entry><entry>HOME</entry></row> +<row><entry><constant>KEY_INFO</constant></entry><entry>Open On Screen Display</entry><entry>DISPLAY INFORMATION / OSD</entry></row> +<row><entry><constant>KEY_WWW</constant></entry><entry>Open the default browser</entry><entry>WEB</entry></row> +<row><entry><constant>KEY_UP</constant></entry><entry>Up key</entry><entry>UP</entry></row> +<row><entry><constant>KEY_DOWN</constant></entry><entry>Down key</entry><entry>DOWN</entry></row> +<row><entry><constant>KEY_LEFT</constant></entry><entry>Left key</entry><entry>LEFT</entry></row> +<row><entry><constant>KEY_RIGHT</constant></entry><entry>Right key</entry><entry>RIGHT</entry></row> + +<row><entry><emphasis role="bold">Miscelaneous keys</emphasis></entry></row> + +<row><entry><constant>KEY_DOT</constant></entry><entry>Return a dot</entry><entry>.</entry></row> +<row><entry><constant>KEY_FN</constant></entry><entry>Select a function</entry><entry>FUNCTION</entry></row> + +</tbody> +</tgroup> +</table> + +<para>It should be noticed that, sometimes, there some fundamental missing keys at some cheaper IR's. Due to that, it is recommended to:</para> + +<table pgwide="1" frame="none" id="rc_keymap_notes"> +<title>Notes</title> +<tgroup cols="1"> +&cs-str; +<tbody valign="top"> +<row> +<entry>On simpler IR's, without separate channel keys, you need to map UP as <constant>KEY_CHANNELUP</constant></entry> +</row><row> +<entry>On simpler IR's, without separate channel keys, you need to map DOWN as <constant>KEY_CHANNELDOWN</constant></entry> +</row><row> +<entry>On simpler IR's, without separate volume keys, you need to map LEFT as <constant>KEY_VOLUMEDOWN</constant></entry> +</row><row> +<entry>On simpler IR's, without separate volume keys, you need to map RIGHT as <constant>KEY_VOLUMEUP</constant></entry> +</row> +</tbody> +</tgroup> +</table> + +</section> + +<section id="Remote_controllers_table_change"> +<title>Changing default Remote Controller mappings</title> +<para>The event interface provides two ioctls to be used against +the /dev/input/event device, to allow changing the default +keymapping.</para> + +<para>This program demonstrates how to replace the keymap tables.</para> +&sub-keytable-c; +</section> diff --git a/Documentation/DocBook/v4l/v4l2.xml b/Documentation/DocBook/v4l/v4l2.xml new file mode 100644 index 0000000..9780172 --- /dev/null +++ b/Documentation/DocBook/v4l/v4l2.xml @@ -0,0 +1,481 @@ + <partinfo> + <authorgroup> + <author> + <firstname>Michael</firstname> + <surname>Schimek</surname> + <othername role="mi">H</othername> + <affiliation> + <address> + <email>mschimek@gmx.at</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Bill</firstname> + <surname>Dirks</surname> + <!-- Commented until Bill opts in to be spammed. + <affiliation> + <address> + <email>bill@thedirks.org</email> + </address> + </affiliation> --> + <contrib>Original author of the V4L2 API and +documentation.</contrib> + </author> + + <author> + <firstname>Hans</firstname> + <surname>Verkuil</surname> + <contrib>Designed and documented the VIDIOC_LOG_STATUS ioctl, +the extended control ioctls and major parts of the sliced VBI +API.</contrib> + <affiliation> + <address> + <email>hverkuil@xs4all.nl</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Martin</firstname> + <surname>Rubli</surname> + <!-- + <affiliation> + <address> + <email>martin_rubli@logitech.com</email> + </address> + </affiliation> --> + <contrib>Designed and documented the VIDIOC_ENUM_FRAMESIZES +and VIDIOC_ENUM_FRAMEINTERVALS ioctls.</contrib> + </author> + + <author> + <firstname>Andy</firstname> + <surname>Walls</surname> + <contrib>Documented the fielded V4L2_MPEG_STREAM_VBI_FMT_IVTV +MPEG stream embedded, sliced VBI data format in this specification. +</contrib> + <affiliation> + <address> + <email>awalls@radix.net</email> + </address> + </affiliation> + </author> + + <author> + <firstname>Mauro</firstname> + <surname>Carvalho Chehab</surname> + <contrib>Documented libv4l, designed and added v4l2grab example, +Remote Controller chapter.</contrib> + <affiliation> + <address> + <email>mchehab@redhat.com</email> + </address> + </affiliation> + </author> + </authorgroup> + + <copyright> + <year>1999</year> + <year>2000</year> + <year>2001</year> + <year>2002</year> + <year>2003</year> + <year>2004</year> + <year>2005</year> + <year>2006</year> + <year>2007</year> + <year>2008</year> + <year>2009</year> + <holder>Bill Dirks, Michael H. Schimek, Hans Verkuil, Martin +Rubli, Andy Walls, Mauro Carvalho Chehab</holder> + </copyright> + <legalnotice> + <para>Except when explicitly stated as GPL, programming examples within + this part can be used and distributed without restrictions.</para> + </legalnotice> + <revhistory> + <!-- Put document revisions here, newest first. --> + <!-- API revisions (changes and additions of defines, enums, +structs, ioctls) must be noted in more detail in the history chapter +(compat.sgml), along with the possible impact on existing drivers and +applications. --> + + <revision> + <revnumber>2.6.32</revnumber> + <date>2009-08-31</date> + <authorinitials>mcc</authorinitials> + <revremark>Now, revisions will match the kernel version where +the V4L2 API changes will be used by the Linux Kernel. +Also added Remote Controller chapter.</revremark> + </revision> + + <revision> + <revnumber>0.29</revnumber> + <date>2009-08-26</date> + <authorinitials>ev</authorinitials> + <revremark>Added documentation for string controls and for FM Transmitter controls.</revremark> + </revision> + + <revision> + <revnumber>0.28</revnumber> + <date>2009-08-26</date> + <authorinitials>gl</authorinitials> + <revremark>Added V4L2_CID_BAND_STOP_FILTER documentation.</revremark> + </revision> + + <revision> + <revnumber>0.27</revnumber> + <date>2009-08-15</date> + <authorinitials>mcc</authorinitials> + <revremark>Added libv4l and Remote Controller documentation; +added v4l2grab and keytable application examples.</revremark> + </revision> + + <revision> + <revnumber>0.26</revnumber> + <date>2009-07-23</date> + <authorinitials>hv</authorinitials> + <revremark>Finalized the RDS capture API. Added modulator and RDS encoder +capabilities. Added support for string controls.</revremark> + </revision> + + <revision> + <revnumber>0.25</revnumber> + <date>2009-01-18</date> + <authorinitials>hv</authorinitials> + <revremark>Added pixel formats VYUY, NV16 and NV61, and changed +the debug ioctls VIDIOC_DBG_G/S_REGISTER and VIDIOC_DBG_G_CHIP_IDENT. +Added camera controls V4L2_CID_ZOOM_ABSOLUTE, V4L2_CID_ZOOM_RELATIVE, +V4L2_CID_ZOOM_CONTINUOUS and V4L2_CID_PRIVACY.</revremark> + </revision> + + <revision> + <revnumber>0.24</revnumber> + <date>2008-03-04</date> + <authorinitials>mhs</authorinitials> + <revremark>Added pixel formats Y16 and SBGGR16, new controls +and a camera controls class. Removed VIDIOC_G/S_MPEGCOMP.</revremark> + </revision> + + <revision> + <revnumber>0.23</revnumber> + <date>2007-08-30</date> + <authorinitials>mhs</authorinitials> + <revremark>Fixed a typo in VIDIOC_DBG_G/S_REGISTER. +Clarified the byte order of packed pixel formats.</revremark> + </revision> + + <revision> + <revnumber>0.22</revnumber> + <date>2007-08-29</date> + <authorinitials>mhs</authorinitials> + <revremark>Added the Video Output Overlay interface, new MPEG +controls, V4L2_FIELD_INTERLACED_TB and V4L2_FIELD_INTERLACED_BT, +VIDIOC_DBG_G/S_REGISTER, VIDIOC_(TRY_)ENCODER_CMD, +VIDIOC_G_CHIP_IDENT, VIDIOC_G_ENC_INDEX, new pixel formats. +Clarifications in the cropping chapter, about RGB pixel formats, the +mmap(), poll(), select(), read() and write() functions. Typographical +fixes.</revremark> + </revision> + + <revision> + <revnumber>0.21</revnumber> + <date>2006-12-19</date> + <authorinitials>mhs</authorinitials> + <revremark>Fixed a link in the VIDIOC_G_EXT_CTRLS section.</revremark> + </revision> + + <revision> + <revnumber>0.20</revnumber> + <date>2006-11-24</date> + <authorinitials>mhs</authorinitials> + <revremark>Clarified the purpose of the audioset field in +struct v4l2_input and v4l2_output.</revremark> + </revision> + + <revision> + <revnumber>0.19</revnumber> + <date>2006-10-19</date> + <authorinitials>mhs</authorinitials> + <revremark>Documented V4L2_PIX_FMT_RGB444.</revremark> + </revision> + + <revision> + <revnumber>0.18</revnumber> + <date>2006-10-18</date> + <authorinitials>mhs</authorinitials> + <revremark>Added the description of extended controls by Hans +Verkuil. Linked V4L2_PIX_FMT_MPEG to V4L2_CID_MPEG_STREAM_TYPE.</revremark> + </revision> + + <revision> + <revnumber>0.17</revnumber> + <date>2006-10-12</date> + <authorinitials>mhs</authorinitials> + <revremark>Corrected V4L2_PIX_FMT_HM12 description.</revremark> + </revision> + + <revision> + <revnumber>0.16</revnumber> + <date>2006-10-08</date> + <authorinitials>mhs</authorinitials> + <revremark>VIDIOC_ENUM_FRAMESIZES and +VIDIOC_ENUM_FRAMEINTERVALS are now part of the API.</revremark> + </revision> + + <revision> + <revnumber>0.15</revnumber> + <date>2006-09-23</date> + <authorinitials>mhs</authorinitials> + <revremark>Cleaned up the bibliography, added BT.653 and +BT.1119. capture.c/start_capturing() for user pointer I/O did not +initialize the buffer index. Documented the V4L MPEG and MJPEG +VID_TYPEs and V4L2_PIX_FMT_SBGGR8. Updated the list of reserved pixel +formats. See the history chapter for API changes.</revremark> + </revision> + + <revision> + <revnumber>0.14</revnumber> + <date>2006-09-14</date> + <authorinitials>mr</authorinitials> + <revremark>Added VIDIOC_ENUM_FRAMESIZES and +VIDIOC_ENUM_FRAMEINTERVALS proposal for frame format enumeration of +digital devices.</revremark> + </revision> + + <revision> + <revnumber>0.13</revnumber> + <date>2006-04-07</date> + <authorinitials>mhs</authorinitials> + <revremark>Corrected the description of struct v4l2_window +clips. New V4L2_STD_ and V4L2_TUNER_MODE_LANG1_LANG2 +defines.</revremark> + </revision> + + <revision> + <revnumber>0.12</revnumber> + <date>2006-02-03</date> + <authorinitials>mhs</authorinitials> + <revremark>Corrected the description of struct +v4l2_captureparm and v4l2_outputparm.</revremark> + </revision> + + <revision> + <revnumber>0.11</revnumber> + <date>2006-01-27</date> + <authorinitials>mhs</authorinitials> + <revremark>Improved the description of struct +v4l2_tuner.</revremark> + </revision> + + <revision> + <revnumber>0.10</revnumber> + <date>2006-01-10</date> + <authorinitials>mhs</authorinitials> + <revremark>VIDIOC_G_INPUT and VIDIOC_S_PARM +clarifications.</revremark> + </revision> + + <revision> + <revnumber>0.9</revnumber> + <date>2005-11-27</date> + <authorinitials>mhs</authorinitials> + <revremark>Improved the 525 line numbering diagram. Hans +Verkuil and I rewrote the sliced VBI section. He also contributed a +VIDIOC_LOG_STATUS page. Fixed VIDIOC_S_STD call in the video standard +selection example. Various updates.</revremark> + </revision> + + <revision> + <revnumber>0.8</revnumber> + <date>2004-10-04</date> + <authorinitials>mhs</authorinitials> + <revremark>Somehow a piece of junk slipped into the capture +example, removed.</revremark> + </revision> + + <revision> + <revnumber>0.7</revnumber> + <date>2004-09-19</date> + <authorinitials>mhs</authorinitials> + <revremark>Fixed video standard selection, control +enumeration, downscaling and aspect example. Added read and user +pointer i/o to video capture example.</revremark> + </revision> + + <revision> + <revnumber>0.6</revnumber> + <date>2004-08-01</date> + <authorinitials>mhs</authorinitials> + <revremark>v4l2_buffer changes, added video capture example, +various corrections.</revremark> + </revision> + + <revision> + <revnumber>0.5</revnumber> + <date>2003-11-05</date> + <authorinitials>mhs</authorinitials> + <revremark>Pixel format erratum.</revremark> + </revision> + + <revision> + <revnumber>0.4</revnumber> + <date>2003-09-17</date> + <authorinitials>mhs</authorinitials> + <revremark>Corrected source and Makefile to generate a PDF. +SGML fixes. Added latest API changes. Closed gaps in the history +chapter.</revremark> + </revision> + + <revision> + <revnumber>0.3</revnumber> + <date>2003-02-05</date> + <authorinitials>mhs</authorinitials> + <revremark>Another draft, more corrections.</revremark> + </revision> + + <revision> + <revnumber>0.2</revnumber> + <date>2003-01-15</date> + <authorinitials>mhs</authorinitials> + <revremark>Second draft, with corrections pointed out by Gerd +Knorr.</revremark> + </revision> + + <revision> + <revnumber>0.1</revnumber> + <date>2002-12-01</date> + <authorinitials>mhs</authorinitials> + <revremark>First draft, based on documentation by Bill Dirks +and discussions on the V4L mailing list.</revremark> + </revision> + </revhistory> +</partinfo> + +<title>Video for Linux Two API Specification</title> + <subtitle>Revision 2.6.32</subtitle> + + <chapter id="common"> + &sub-common; + </chapter> + + <chapter id="pixfmt"> + &sub-pixfmt; + </chapter> + + <chapter id="io"> + &sub-io; + </chapter> + + <chapter id="devices"> + <title>Interfaces</title> + + <section id="capture"> &sub-dev-capture; </section> + <section id="overlay"> &sub-dev-overlay; </section> + <section id="output"> &sub-dev-output; </section> + <section id="osd"> &sub-dev-osd; </section> + <section id="codec"> &sub-dev-codec; </section> + <section id="effect"> &sub-dev-effect; </section> + <section id="raw-vbi"> &sub-dev-raw-vbi; </section> + <section id="sliced"> &sub-dev-sliced-vbi; </section> + <section id="ttx"> &sub-dev-teletext; </section> + <section id="radio"> &sub-dev-radio; </section> + <section id="rds"> &sub-dev-rds; </section> + </chapter> + + <chapter id="driver"> + &sub-driver; + </chapter> + + <chapter id="libv4l"> + &sub-libv4l; + </chapter> + + <chapter id="compat"> + &sub-compat; + </chapter> + + <appendix id="function_ref"> + <title>Function Reference</title> + <reference id="user-func"> + + <!-- Keep this alphabetically sorted. --> + + &sub-close; + &sub-ioctl; + <!-- All ioctls go here. --> + &sub-cropcap; + &sub-dbg-g-chip-ident; + &sub-dbg-g-register; + &sub-encoder-cmd; + &sub-enumaudio; + &sub-enumaudioout; + &sub-enum-fmt; + &sub-enum-framesizes; + &sub-enum-frameintervals; + &sub-enuminput; + &sub-enumoutput; + &sub-enumstd; + &sub-g-audio; + &sub-g-audioout; + &sub-g-crop; + &sub-g-ctrl; + &sub-g-enc-index; + &sub-g-ext-ctrls; + &sub-g-fbuf; + &sub-g-fmt; + &sub-g-frequency; + &sub-g-input; + &sub-g-jpegcomp; + &sub-g-modulator; + &sub-g-output; + &sub-g-parm; + &sub-g-priority; + &sub-g-sliced-vbi-cap; + &sub-g-std; + &sub-g-tuner; + &sub-log-status; + &sub-overlay; + &sub-qbuf; + &sub-querybuf; + &sub-querycap; + &sub-queryctrl; + &sub-querystd; + &sub-reqbufs; + &sub-s-hw-freq-seek; + &sub-streamon; + <!-- End of ioctls. --> + &sub-mmap; + &sub-munmap; + &sub-open; + &sub-poll; + &sub-read; + &sub-select; + &sub-write; + </reference> + </appendix> + + <appendix id="videodev"> + <title>Video For Linux Two Header File</title> + &sub-videodev2-h; + </appendix> + + <appendix id="capture-example"> + <title>Video Capture Example</title> + &sub-capture-c; + </appendix> + + <appendix id="v4l2grab-example"> + <title>Video Grabber example using libv4l</title> + <para>This program demonstrates how to grab V4L2 images in ppm format by +using libv4l handlers. The advantage is that this grabber can potentially work +with any V4L2 driver.</para> + &sub-v4l2grab-c; + </appendix> + + &sub-media-indices; + + &sub-biblio; + diff --git a/Documentation/DocBook/v4l/v4l2grab.c.xml b/Documentation/DocBook/v4l/v4l2grab.c.xml new file mode 100644 index 0000000..bed12e4 --- /dev/null +++ b/Documentation/DocBook/v4l/v4l2grab.c.xml @@ -0,0 +1,164 @@ +<programlisting> +/* V4L2 video picture grabber + Copyright (C) 2009 Mauro Carvalho Chehab <mchehab@infradead.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> +#include <errno.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/mman.h> +#include <linux/videodev2.h> +#include "../libv4l/include/libv4l2.h" + +#define CLEAR(x) memset(&(x), 0, sizeof(x)) + +struct buffer { + void *start; + size_t length; +}; + +static void xioctl(int fh, int request, void *arg) +{ + int r; + + do { + r = v4l2_ioctl(fh, request, arg); + } while (r == -1 && ((errno == EINTR) || (errno == EAGAIN))); + + if (r == -1) { + fprintf(stderr, "error %d, %s\n", errno, strerror(errno)); + exit(EXIT_FAILURE); + } +} + +int main(int argc, char **argv) +{ + struct <link linkend="v4l2-format">v4l2_format</link> fmt; + struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf; + struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> req; + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + fd_set fds; + struct timeval tv; + int r, fd = -1; + unsigned int i, n_buffers; + char *dev_name = "/dev/video0"; + char out_name[256]; + FILE *fout; + struct buffer *buffers; + + fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK, 0); + if (fd < 0) { + perror("Cannot open device"); + exit(EXIT_FAILURE); + } + + CLEAR(fmt); + fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + fmt.fmt.pix.width = 640; + fmt.fmt.pix.height = 480; + fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB24; + fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; + xioctl(fd, VIDIOC_S_FMT, &fmt); + if (fmt.fmt.pix.pixelformat != V4L2_PIX_FMT_RGB24) { + printf("Libv4l didn't accept RGB24 format. Can't proceed.\n"); + exit(EXIT_FAILURE); + } + if ((fmt.fmt.pix.width != 640) || (fmt.fmt.pix.height != 480)) + printf("Warning: driver is sending image at %dx%d\n", + fmt.fmt.pix.width, fmt.fmt.pix.height); + + CLEAR(req); + req.count = 2; + req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + req.memory = V4L2_MEMORY_MMAP; + xioctl(fd, VIDIOC_REQBUFS, &req); + + buffers = calloc(req.count, sizeof(*buffers)); + for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { + CLEAR(buf); + + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = n_buffers; + + xioctl(fd, VIDIOC_QUERYBUF, &buf); + + buffers[n_buffers].length = buf.length; + buffers[n_buffers].start = v4l2_mmap(NULL, buf.length, + PROT_READ | PROT_WRITE, MAP_SHARED, + fd, buf.m.offset); + + if (MAP_FAILED == buffers[n_buffers].start) { + perror("mmap"); + exit(EXIT_FAILURE); + } + } + + for (i = 0; i < n_buffers; ++i) { + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + buf.index = i; + xioctl(fd, VIDIOC_QBUF, &buf); + } + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + + xioctl(fd, VIDIOC_STREAMON, &type); + for (i = 0; i < 20; i++) { + do { + FD_ZERO(&fds); + FD_SET(fd, &fds); + + /* Timeout. */ + tv.tv_sec = 2; + tv.tv_usec = 0; + + r = select(fd + 1, &fds, NULL, NULL, &tv); + } while ((r == -1 && (errno = EINTR))); + if (r == -1) { + perror("select"); + return errno; + } + + CLEAR(buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_MMAP; + xioctl(fd, VIDIOC_DQBUF, &buf); + + sprintf(out_name, "out%03d.ppm", i); + fout = fopen(out_name, "w"); + if (!fout) { + perror("Cannot open image"); + exit(EXIT_FAILURE); + } + fprintf(fout, "P6\n%d %d 255\n", + fmt.fmt.pix.width, fmt.fmt.pix.height); + fwrite(buffers[buf.index].start, buf.bytesused, 1, fout); + fclose(fout); + + xioctl(fd, VIDIOC_QBUF, &buf); + } + + type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + xioctl(fd, VIDIOC_STREAMOFF, &type); + for (i = 0; i < n_buffers; ++i) + v4l2_munmap(buffers[i].start, buffers[i].length); + v4l2_close(fd); + + return 0; +} +</programlisting> diff --git a/Documentation/DocBook/v4l/vbi_525.gif b/Documentation/DocBook/v4l/vbi_525.gif Binary files differnew file mode 100644 index 0000000..5580b69 --- /dev/null +++ b/Documentation/DocBook/v4l/vbi_525.gif diff --git a/Documentation/DocBook/v4l/vbi_525.pdf b/Documentation/DocBook/v4l/vbi_525.pdf Binary files differnew file mode 100644 index 0000000..9e72c25 --- /dev/null +++ b/Documentation/DocBook/v4l/vbi_525.pdf diff --git a/Documentation/DocBook/v4l/vbi_625.gif b/Documentation/DocBook/v4l/vbi_625.gif Binary files differnew file mode 100644 index 0000000..34e3251 --- /dev/null +++ b/Documentation/DocBook/v4l/vbi_625.gif diff --git a/Documentation/DocBook/v4l/vbi_625.pdf b/Documentation/DocBook/v4l/vbi_625.pdf Binary files differnew file mode 100644 index 0000000..765235e --- /dev/null +++ b/Documentation/DocBook/v4l/vbi_625.pdf diff --git a/Documentation/DocBook/v4l/vbi_hsync.gif b/Documentation/DocBook/v4l/vbi_hsync.gif Binary files differnew file mode 100644 index 0000000..b02434d --- /dev/null +++ b/Documentation/DocBook/v4l/vbi_hsync.gif diff --git a/Documentation/DocBook/v4l/vbi_hsync.pdf b/Documentation/DocBook/v4l/vbi_hsync.pdf Binary files differnew file mode 100644 index 0000000..200b668 --- /dev/null +++ b/Documentation/DocBook/v4l/vbi_hsync.pdf diff --git a/Documentation/DocBook/v4l/videodev2.h.xml b/Documentation/DocBook/v4l/videodev2.h.xml new file mode 100644 index 0000000..6a8e139 --- /dev/null +++ b/Documentation/DocBook/v4l/videodev2.h.xml @@ -0,0 +1,1639 @@ +<programlisting> +/* + * Video for Linux Two header file + * + * Copyright (C) 1999-2007 the contributors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Alternatively you can redistribute this file under the terms of the + * BSD license as stated below: + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. The names of its contributors may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Header file for v4l or V4L2 drivers and applications + * with public API. + * All kernel-specific stuff were moved to media/v4l2-dev.h, so + * no #if __KERNEL tests are allowed here + * + * See http://linuxtv.org for more info + * + * Author: Bill Dirks <bill@thedirks.org> + * Justin Schoeman + * Hans Verkuil <hverkuil@xs4all.nl> + * et al. + */ +#ifndef __LINUX_VIDEODEV2_H +#define __LINUX_VIDEODEV2_H + +#ifdef __KERNEL__ +#include <linux/time.h> /* need struct timeval */ +#else +#include <sys/time.h> +#endif +#include <linux/compiler.h> +#include <linux/ioctl.h> +#include <linux/types.h> + +/* + * Common stuff for both V4L1 and V4L2 + * Moved from videodev.h + */ +#define VIDEO_MAX_FRAME 32 + +#ifndef __KERNEL__ + +/* These defines are V4L1 specific and should not be used with the V4L2 API! + They will be removed from this header in the future. */ + +#define VID_TYPE_CAPTURE 1 /* Can capture */ +#define VID_TYPE_TUNER 2 /* Can tune */ +#define VID_TYPE_TELETEXT 4 /* Does teletext */ +#define VID_TYPE_OVERLAY 8 /* Overlay onto frame buffer */ +#define VID_TYPE_CHROMAKEY 16 /* Overlay by chromakey */ +#define VID_TYPE_CLIPPING 32 /* Can clip */ +#define VID_TYPE_FRAMERAM 64 /* Uses the frame buffer memory */ +#define VID_TYPE_SCALES 128 /* Scalable */ +#define VID_TYPE_MONOCHROME 256 /* Monochrome only */ +#define VID_TYPE_SUBCAPTURE 512 /* Can capture subareas of the image */ +#define VID_TYPE_MPEG_DECODER 1024 /* Can decode MPEG streams */ +#define VID_TYPE_MPEG_ENCODER 2048 /* Can encode MPEG streams */ +#define VID_TYPE_MJPEG_DECODER 4096 /* Can decode MJPEG streams */ +#define VID_TYPE_MJPEG_ENCODER 8192 /* Can encode MJPEG streams */ +#endif + +/* + * M I S C E L L A N E O U S + */ + +/* Four-character-code (FOURCC) */ +#define v4l2_fourcc(a, b, c, d)\ + ((__u32)(a) | ((__u32)(b) << 8) | ((__u32)(c) << 16) | ((__u32)(d) << 24)) + +/* + * E N U M S + */ +enum <link linkend="v4l2-field">v4l2_field</link> { + V4L2_FIELD_ANY = 0, /* driver can choose from none, + top, bottom, interlaced + depending on whatever it thinks + is approximate ... */ + V4L2_FIELD_NONE = 1, /* this device has no fields ... */ + V4L2_FIELD_TOP = 2, /* top field only */ + V4L2_FIELD_BOTTOM = 3, /* bottom field only */ + V4L2_FIELD_INTERLACED = 4, /* both fields interlaced */ + V4L2_FIELD_SEQ_TB = 5, /* both fields sequential into one + buffer, top-bottom order */ + V4L2_FIELD_SEQ_BT = 6, /* same as above + bottom-top order */ + V4L2_FIELD_ALTERNATE = 7, /* both fields alternating into + separate buffers */ + V4L2_FIELD_INTERLACED_TB = 8, /* both fields interlaced, top field + first and the top field is + transmitted first */ + V4L2_FIELD_INTERLACED_BT = 9, /* both fields interlaced, top field + first and the bottom field is + transmitted first */ +}; +#define V4L2_FIELD_HAS_TOP(field) \ + ((field) == V4L2_FIELD_TOP ||\ + (field) == V4L2_FIELD_INTERLACED ||\ + (field) == V4L2_FIELD_INTERLACED_TB ||\ + (field) == V4L2_FIELD_INTERLACED_BT ||\ + (field) == V4L2_FIELD_SEQ_TB ||\ + (field) == V4L2_FIELD_SEQ_BT) +#define V4L2_FIELD_HAS_BOTTOM(field) \ + ((field) == V4L2_FIELD_BOTTOM ||\ + (field) == V4L2_FIELD_INTERLACED ||\ + (field) == V4L2_FIELD_INTERLACED_TB ||\ + (field) == V4L2_FIELD_INTERLACED_BT ||\ + (field) == V4L2_FIELD_SEQ_TB ||\ + (field) == V4L2_FIELD_SEQ_BT) +#define V4L2_FIELD_HAS_BOTH(field) \ + ((field) == V4L2_FIELD_INTERLACED ||\ + (field) == V4L2_FIELD_INTERLACED_TB ||\ + (field) == V4L2_FIELD_INTERLACED_BT ||\ + (field) == V4L2_FIELD_SEQ_TB ||\ + (field) == V4L2_FIELD_SEQ_BT) + +enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> { + V4L2_BUF_TYPE_VIDEO_CAPTURE = 1, + V4L2_BUF_TYPE_VIDEO_OUTPUT = 2, + V4L2_BUF_TYPE_VIDEO_OVERLAY = 3, + V4L2_BUF_TYPE_VBI_CAPTURE = 4, + V4L2_BUF_TYPE_VBI_OUTPUT = 5, + V4L2_BUF_TYPE_SLICED_VBI_CAPTURE = 6, + V4L2_BUF_TYPE_SLICED_VBI_OUTPUT = 7, +#if 1 /*KEEP*/ + /* Experimental */ + V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY = 8, +#endif + V4L2_BUF_TYPE_PRIVATE = 0x80, +}; + +enum <link linkend="v4l2-ctrl-type">v4l2_ctrl_type</link> { + V4L2_CTRL_TYPE_INTEGER = 1, + V4L2_CTRL_TYPE_BOOLEAN = 2, + V4L2_CTRL_TYPE_MENU = 3, + V4L2_CTRL_TYPE_BUTTON = 4, + V4L2_CTRL_TYPE_INTEGER64 = 5, + V4L2_CTRL_TYPE_CTRL_CLASS = 6, + V4L2_CTRL_TYPE_STRING = 7, +}; + +enum <link linkend="v4l2-tuner-type">v4l2_tuner_type</link> { + V4L2_TUNER_RADIO = 1, + V4L2_TUNER_ANALOG_TV = 2, + V4L2_TUNER_DIGITAL_TV = 3, +}; + +enum <link linkend="v4l2-memory">v4l2_memory</link> { + V4L2_MEMORY_MMAP = 1, + V4L2_MEMORY_USERPTR = 2, + V4L2_MEMORY_OVERLAY = 3, +}; + +/* see also http://vektor.theorem.ca/graphics/ycbcr/ */ +enum <link linkend="v4l2-colorspace">v4l2_colorspace</link> { + /* ITU-R 601 -- broadcast NTSC/PAL */ + V4L2_COLORSPACE_SMPTE170M = 1, + + /* 1125-Line (US) HDTV */ + V4L2_COLORSPACE_SMPTE240M = 2, + + /* HD and modern captures. */ + V4L2_COLORSPACE_REC709 = 3, + + /* broken BT878 extents (601, luma range 16-253 instead of 16-235) */ + V4L2_COLORSPACE_BT878 = 4, + + /* These should be useful. Assume 601 extents. */ + V4L2_COLORSPACE_470_SYSTEM_M = 5, + V4L2_COLORSPACE_470_SYSTEM_BG = 6, + + /* I know there will be cameras that send this. So, this is + * unspecified chromaticities and full 0-255 on each of the + * Y'CbCr components + */ + V4L2_COLORSPACE_JPEG = 7, + + /* For RGB colourspaces, this is probably a good start. */ + V4L2_COLORSPACE_SRGB = 8, +}; + +enum <link linkend="v4l2-priority">v4l2_priority</link> { + V4L2_PRIORITY_UNSET = 0, /* not initialized */ + V4L2_PRIORITY_BACKGROUND = 1, + V4L2_PRIORITY_INTERACTIVE = 2, + V4L2_PRIORITY_RECORD = 3, + V4L2_PRIORITY_DEFAULT = V4L2_PRIORITY_INTERACTIVE, +}; + +struct <link linkend="v4l2-rect">v4l2_rect</link> { + __s32 left; + __s32 top; + __s32 width; + __s32 height; +}; + +struct <link linkend="v4l2-fract">v4l2_fract</link> { + __u32 numerator; + __u32 denominator; +}; + +/* + * D R I V E R C A P A B I L I T I E S + */ +struct <link linkend="v4l2-capability">v4l2_capability</link> { + __u8 driver[16]; /* i.e.ie; "bttv" */ + __u8 card[32]; /* i.e.ie; "Hauppauge WinTV" */ + __u8 bus_info[32]; /* "PCI:" + pci_name(pci_dev) */ + __u32 version; /* should use KERNEL_VERSION() */ + __u32 capabilities; /* Device capabilities */ + __u32 reserved[4]; +}; + +/* Values for 'capabilities' field */ +#define V4L2_CAP_VIDEO_CAPTURE 0x00000001 /* Is a video capture device */ +#define V4L2_CAP_VIDEO_OUTPUT 0x00000002 /* Is a video output device */ +#define V4L2_CAP_VIDEO_OVERLAY 0x00000004 /* Can do video overlay */ +#define V4L2_CAP_VBI_CAPTURE 0x00000010 /* Is a raw VBI capture device */ +#define V4L2_CAP_VBI_OUTPUT 0x00000020 /* Is a raw VBI output device */ +#define V4L2_CAP_SLICED_VBI_CAPTURE 0x00000040 /* Is a sliced VBI capture device */ +#define V4L2_CAP_SLICED_VBI_OUTPUT 0x00000080 /* Is a sliced VBI output device */ +#define V4L2_CAP_RDS_CAPTURE 0x00000100 /* RDS data capture */ +#define V4L2_CAP_VIDEO_OUTPUT_OVERLAY 0x00000200 /* Can do video output overlay */ +#define V4L2_CAP_HW_FREQ_SEEK 0x00000400 /* Can do hardware frequency seek */ +#define V4L2_CAP_RDS_OUTPUT 0x00000800 /* Is an RDS encoder */ + +#define V4L2_CAP_TUNER 0x00010000 /* has a tuner */ +#define V4L2_CAP_AUDIO 0x00020000 /* has audio support */ +#define V4L2_CAP_RADIO 0x00040000 /* is a radio device */ +#define V4L2_CAP_MODULATOR 0x00080000 /* has a modulator */ + +#define V4L2_CAP_READWRITE 0x01000000 /* read/write systemcalls */ +#define V4L2_CAP_ASYNCIO 0x02000000 /* async I/O */ +#define V4L2_CAP_STREAMING 0x04000000 /* streaming I/O ioctls */ + +/* + * V I D E O I M A G E F O R M A T + */ +struct <link linkend="v4l2-pix-format">v4l2_pix_format</link> { + __u32 width; + __u32 height; + __u32 pixelformat; + enum <link linkend="v4l2-field">v4l2_field</link> field; + __u32 bytesperline; /* for padding, zero if unused */ + __u32 sizeimage; + enum <link linkend="v4l2-colorspace">v4l2_colorspace</link> colorspace; + __u32 priv; /* private data, depends on pixelformat */ +}; + +/* Pixel format FOURCC depth Description */ + +/* RGB formats */ +#define <link linkend="V4L2-PIX-FMT-RGB332">V4L2_PIX_FMT_RGB332</link> v4l2_fourcc('R', 'G', 'B', '1') /* 8 RGB-3-3-2 */ +#define <link linkend="V4L2-PIX-FMT-RGB444">V4L2_PIX_FMT_RGB444</link> v4l2_fourcc('R', '4', '4', '4') /* 16 xxxxrrrr ggggbbbb */ +#define <link linkend="V4L2-PIX-FMT-RGB555">V4L2_PIX_FMT_RGB555</link> v4l2_fourcc('R', 'G', 'B', 'O') /* 16 RGB-5-5-5 */ +#define <link linkend="V4L2-PIX-FMT-RGB565">V4L2_PIX_FMT_RGB565</link> v4l2_fourcc('R', 'G', 'B', 'P') /* 16 RGB-5-6-5 */ +#define <link linkend="V4L2-PIX-FMT-RGB555X">V4L2_PIX_FMT_RGB555X</link> v4l2_fourcc('R', 'G', 'B', 'Q') /* 16 RGB-5-5-5 BE */ +#define <link linkend="V4L2-PIX-FMT-RGB565X">V4L2_PIX_FMT_RGB565X</link> v4l2_fourcc('R', 'G', 'B', 'R') /* 16 RGB-5-6-5 BE */ +#define <link linkend="V4L2-PIX-FMT-BGR24">V4L2_PIX_FMT_BGR24</link> v4l2_fourcc('B', 'G', 'R', '3') /* 24 BGR-8-8-8 */ +#define <link linkend="V4L2-PIX-FMT-RGB24">V4L2_PIX_FMT_RGB24</link> v4l2_fourcc('R', 'G', 'B', '3') /* 24 RGB-8-8-8 */ +#define <link linkend="V4L2-PIX-FMT-BGR32">V4L2_PIX_FMT_BGR32</link> v4l2_fourcc('B', 'G', 'R', '4') /* 32 BGR-8-8-8-8 */ +#define <link linkend="V4L2-PIX-FMT-RGB32">V4L2_PIX_FMT_RGB32</link> v4l2_fourcc('R', 'G', 'B', '4') /* 32 RGB-8-8-8-8 */ + +/* Grey formats */ +#define <link linkend="V4L2-PIX-FMT-GREY">V4L2_PIX_FMT_GREY</link> v4l2_fourcc('G', 'R', 'E', 'Y') /* 8 Greyscale */ +#define <link linkend="V4L2-PIX-FMT-Y16">V4L2_PIX_FMT_Y16</link> v4l2_fourcc('Y', '1', '6', ' ') /* 16 Greyscale */ + +/* Palette formats */ +#define <link linkend="V4L2-PIX-FMT-PAL8">V4L2_PIX_FMT_PAL8</link> v4l2_fourcc('P', 'A', 'L', '8') /* 8 8-bit palette */ + +/* Luminance+Chrominance formats */ +#define <link linkend="V4L2-PIX-FMT-YVU410">V4L2_PIX_FMT_YVU410</link> v4l2_fourcc('Y', 'V', 'U', '9') /* 9 YVU 4:1:0 */ +#define <link linkend="V4L2-PIX-FMT-YVU420">V4L2_PIX_FMT_YVU420</link> v4l2_fourcc('Y', 'V', '1', '2') /* 12 YVU 4:2:0 */ +#define <link linkend="V4L2-PIX-FMT-YUYV">V4L2_PIX_FMT_YUYV</link> v4l2_fourcc('Y', 'U', 'Y', 'V') /* 16 YUV 4:2:2 */ +#define <link linkend="V4L2-PIX-FMT-YYUV">V4L2_PIX_FMT_YYUV</link> v4l2_fourcc('Y', 'Y', 'U', 'V') /* 16 YUV 4:2:2 */ +#define <link linkend="V4L2-PIX-FMT-YVYU">V4L2_PIX_FMT_YVYU</link> v4l2_fourcc('Y', 'V', 'Y', 'U') /* 16 YVU 4:2:2 */ +#define <link linkend="V4L2-PIX-FMT-UYVY">V4L2_PIX_FMT_UYVY</link> v4l2_fourcc('U', 'Y', 'V', 'Y') /* 16 YUV 4:2:2 */ +#define <link linkend="V4L2-PIX-FMT-VYUY">V4L2_PIX_FMT_VYUY</link> v4l2_fourcc('V', 'Y', 'U', 'Y') /* 16 YUV 4:2:2 */ +#define <link linkend="V4L2-PIX-FMT-YUV422P">V4L2_PIX_FMT_YUV422P</link> v4l2_fourcc('4', '2', '2', 'P') /* 16 YVU422 planar */ +#define <link linkend="V4L2-PIX-FMT-YUV411P">V4L2_PIX_FMT_YUV411P</link> v4l2_fourcc('4', '1', '1', 'P') /* 16 YVU411 planar */ +#define <link linkend="V4L2-PIX-FMT-Y41P">V4L2_PIX_FMT_Y41P</link> v4l2_fourcc('Y', '4', '1', 'P') /* 12 YUV 4:1:1 */ +#define <link linkend="V4L2-PIX-FMT-YUV444">V4L2_PIX_FMT_YUV444</link> v4l2_fourcc('Y', '4', '4', '4') /* 16 xxxxyyyy uuuuvvvv */ +#define <link linkend="V4L2-PIX-FMT-YUV555">V4L2_PIX_FMT_YUV555</link> v4l2_fourcc('Y', 'U', 'V', 'O') /* 16 YUV-5-5-5 */ +#define <link linkend="V4L2-PIX-FMT-YUV565">V4L2_PIX_FMT_YUV565</link> v4l2_fourcc('Y', 'U', 'V', 'P') /* 16 YUV-5-6-5 */ +#define <link linkend="V4L2-PIX-FMT-YUV32">V4L2_PIX_FMT_YUV32</link> v4l2_fourcc('Y', 'U', 'V', '4') /* 32 YUV-8-8-8-8 */ +#define <link linkend="V4L2-PIX-FMT-YUV410">V4L2_PIX_FMT_YUV410</link> v4l2_fourcc('Y', 'U', 'V', '9') /* 9 YUV 4:1:0 */ +#define <link linkend="V4L2-PIX-FMT-YUV420">V4L2_PIX_FMT_YUV420</link> v4l2_fourcc('Y', 'U', '1', '2') /* 12 YUV 4:2:0 */ +#define <link linkend="V4L2-PIX-FMT-HI240">V4L2_PIX_FMT_HI240</link> v4l2_fourcc('H', 'I', '2', '4') /* 8 8-bit color */ +#define <link linkend="V4L2-PIX-FMT-HM12">V4L2_PIX_FMT_HM12</link> v4l2_fourcc('H', 'M', '1', '2') /* 8 YUV 4:2:0 16x16 macroblocks */ + +/* two planes -- one Y, one Cr + Cb interleaved */ +#define <link linkend="V4L2-PIX-FMT-NV12">V4L2_PIX_FMT_NV12</link> v4l2_fourcc('N', 'V', '1', '2') /* 12 Y/CbCr 4:2:0 */ +#define <link linkend="V4L2-PIX-FMT-NV21">V4L2_PIX_FMT_NV21</link> v4l2_fourcc('N', 'V', '2', '1') /* 12 Y/CrCb 4:2:0 */ +#define <link linkend="V4L2-PIX-FMT-NV16">V4L2_PIX_FMT_NV16</link> v4l2_fourcc('N', 'V', '1', '6') /* 16 Y/CbCr 4:2:2 */ +#define <link linkend="V4L2-PIX-FMT-NV61">V4L2_PIX_FMT_NV61</link> v4l2_fourcc('N', 'V', '6', '1') /* 16 Y/CrCb 4:2:2 */ + +/* Bayer formats - see http://www.siliconimaging.com/RGB%20Bayer.htm */ +#define <link linkend="V4L2-PIX-FMT-SBGGR8">V4L2_PIX_FMT_SBGGR8</link> v4l2_fourcc('B', 'A', '8', '1') /* 8 BGBG.. GRGR.. */ +#define <link linkend="V4L2-PIX-FMT-SGBRG8">V4L2_PIX_FMT_SGBRG8</link> v4l2_fourcc('G', 'B', 'R', 'G') /* 8 GBGB.. RGRG.. */ +#define <link linkend="V4L2-PIX-FMT-SGRBG8">V4L2_PIX_FMT_SGRBG8</link> v4l2_fourcc('G', 'R', 'B', 'G') /* 8 GRGR.. BGBG.. */ +#define <link linkend="V4L2-PIX-FMT-SGRBG10">V4L2_PIX_FMT_SGRBG10</link> v4l2_fourcc('B', 'A', '1', '0') /* 10bit raw bayer */ + /* 10bit raw bayer DPCM compressed to 8 bits */ +#define <link linkend="V4L2-PIX-FMT-SGRBG10DPCM8">V4L2_PIX_FMT_SGRBG10DPCM8</link> v4l2_fourcc('B', 'D', '1', '0') + /* + * 10bit raw bayer, expanded to 16 bits + * xxxxrrrrrrrrrrxxxxgggggggggg xxxxggggggggggxxxxbbbbbbbbbb... + */ +#define <link linkend="V4L2-PIX-FMT-SBGGR16">V4L2_PIX_FMT_SBGGR16</link> v4l2_fourcc('B', 'Y', 'R', '2') /* 16 BGBG.. GRGR.. */ + +/* compressed formats */ +#define <link linkend="V4L2-PIX-FMT-MJPEG">V4L2_PIX_FMT_MJPEG</link> v4l2_fourcc('M', 'J', 'P', 'G') /* Motion-JPEG */ +#define <link linkend="V4L2-PIX-FMT-JPEG">V4L2_PIX_FMT_JPEG</link> v4l2_fourcc('J', 'P', 'E', 'G') /* JFIF JPEG */ +#define <link linkend="V4L2-PIX-FMT-DV">V4L2_PIX_FMT_DV</link> v4l2_fourcc('d', 'v', 's', 'd') /* 1394 */ +#define <link linkend="V4L2-PIX-FMT-MPEG">V4L2_PIX_FMT_MPEG</link> v4l2_fourcc('M', 'P', 'E', 'G') /* MPEG-1/2/4 */ + +/* Vendor-specific formats */ +#define <link linkend="V4L2-PIX-FMT-WNVA">V4L2_PIX_FMT_WNVA</link> v4l2_fourcc('W', 'N', 'V', 'A') /* Winnov hw compress */ +#define <link linkend="V4L2-PIX-FMT-SN9C10X">V4L2_PIX_FMT_SN9C10X</link> v4l2_fourcc('S', '9', '1', '0') /* SN9C10x compression */ +#define <link linkend="V4L2-PIX-FMT-SN9C20X-I420">V4L2_PIX_FMT_SN9C20X_I420</link> v4l2_fourcc('S', '9', '2', '0') /* SN9C20x YUV 4:2:0 */ +#define <link linkend="V4L2-PIX-FMT-PWC1">V4L2_PIX_FMT_PWC1</link> v4l2_fourcc('P', 'W', 'C', '1') /* pwc older webcam */ +#define <link linkend="V4L2-PIX-FMT-PWC2">V4L2_PIX_FMT_PWC2</link> v4l2_fourcc('P', 'W', 'C', '2') /* pwc newer webcam */ +#define <link linkend="V4L2-PIX-FMT-ET61X251">V4L2_PIX_FMT_ET61X251</link> v4l2_fourcc('E', '6', '2', '5') /* ET61X251 compression */ +#define <link linkend="V4L2-PIX-FMT-SPCA501">V4L2_PIX_FMT_SPCA501</link> v4l2_fourcc('S', '5', '0', '1') /* YUYV per line */ +#define <link linkend="V4L2-PIX-FMT-SPCA505">V4L2_PIX_FMT_SPCA505</link> v4l2_fourcc('S', '5', '0', '5') /* YYUV per line */ +#define <link linkend="V4L2-PIX-FMT-SPCA508">V4L2_PIX_FMT_SPCA508</link> v4l2_fourcc('S', '5', '0', '8') /* YUVY per line */ +#define <link linkend="V4L2-PIX-FMT-SPCA561">V4L2_PIX_FMT_SPCA561</link> v4l2_fourcc('S', '5', '6', '1') /* compressed GBRG bayer */ +#define <link linkend="V4L2-PIX-FMT-PAC207">V4L2_PIX_FMT_PAC207</link> v4l2_fourcc('P', '2', '0', '7') /* compressed BGGR bayer */ +#define <link linkend="V4L2-PIX-FMT-MR97310A">V4L2_PIX_FMT_MR97310A</link> v4l2_fourcc('M', '3', '1', '0') /* compressed BGGR bayer */ +#define <link linkend="V4L2-PIX-FMT-SQ905C">V4L2_PIX_FMT_SQ905C</link> v4l2_fourcc('9', '0', '5', 'C') /* compressed RGGB bayer */ +#define <link linkend="V4L2-PIX-FMT-PJPG">V4L2_PIX_FMT_PJPG</link> v4l2_fourcc('P', 'J', 'P', 'G') /* Pixart 73xx JPEG */ +#define <link linkend="V4L2-PIX-FMT-OV511">V4L2_PIX_FMT_OV511</link> v4l2_fourcc('O', '5', '1', '1') /* ov511 JPEG */ +#define <link linkend="V4L2-PIX-FMT-OV518">V4L2_PIX_FMT_OV518</link> v4l2_fourcc('O', '5', '1', '8') /* ov518 JPEG */ + +/* + * F O R M A T E N U M E R A T I O N + */ +struct <link linkend="v4l2-fmtdesc">v4l2_fmtdesc</link> { + __u32 index; /* Format number */ + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; /* buffer type */ + __u32 flags; + __u8 description[32]; /* Description string */ + __u32 pixelformat; /* Format fourcc */ + __u32 reserved[4]; +}; + +#define V4L2_FMT_FLAG_COMPRESSED 0x0001 +#define V4L2_FMT_FLAG_EMULATED 0x0002 + +#if 1 /*KEEP*/ + /* Experimental Frame Size and frame rate enumeration */ +/* + * F R A M E S I Z E E N U M E R A T I O N + */ +enum <link linkend="v4l2-frmsizetypes">v4l2_frmsizetypes</link> { + V4L2_FRMSIZE_TYPE_DISCRETE = 1, + V4L2_FRMSIZE_TYPE_CONTINUOUS = 2, + V4L2_FRMSIZE_TYPE_STEPWISE = 3, +}; + +struct <link linkend="v4l2-frmsize-discrete">v4l2_frmsize_discrete</link> { + __u32 width; /* Frame width [pixel] */ + __u32 height; /* Frame height [pixel] */ +}; + +struct <link linkend="v4l2-frmsize-stepwise">v4l2_frmsize_stepwise</link> { + __u32 min_width; /* Minimum frame width [pixel] */ + __u32 max_width; /* Maximum frame width [pixel] */ + __u32 step_width; /* Frame width step size [pixel] */ + __u32 min_height; /* Minimum frame height [pixel] */ + __u32 max_height; /* Maximum frame height [pixel] */ + __u32 step_height; /* Frame height step size [pixel] */ +}; + +struct <link linkend="v4l2-frmsizeenum">v4l2_frmsizeenum</link> { + __u32 index; /* Frame size number */ + __u32 pixel_format; /* Pixel format */ + __u32 type; /* Frame size type the device supports. */ + + union { /* Frame size */ + struct <link linkend="v4l2-frmsize-discrete">v4l2_frmsize_discrete</link> discrete; + struct <link linkend="v4l2-frmsize-stepwise">v4l2_frmsize_stepwise</link> stepwise; + }; + + __u32 reserved[2]; /* Reserved space for future use */ +}; + +/* + * F R A M E R A T E E N U M E R A T I O N + */ +enum <link linkend="v4l2-frmivaltypes">v4l2_frmivaltypes</link> { + V4L2_FRMIVAL_TYPE_DISCRETE = 1, + V4L2_FRMIVAL_TYPE_CONTINUOUS = 2, + V4L2_FRMIVAL_TYPE_STEPWISE = 3, +}; + +struct <link linkend="v4l2-frmival-stepwise">v4l2_frmival_stepwise</link> { + struct <link linkend="v4l2-fract">v4l2_fract</link> min; /* Minimum frame interval [s] */ + struct <link linkend="v4l2-fract">v4l2_fract</link> max; /* Maximum frame interval [s] */ + struct <link linkend="v4l2-fract">v4l2_fract</link> step; /* Frame interval step size [s] */ +}; + +struct <link linkend="v4l2-frmivalenum">v4l2_frmivalenum</link> { + __u32 index; /* Frame format index */ + __u32 pixel_format; /* Pixel format */ + __u32 width; /* Frame width */ + __u32 height; /* Frame height */ + __u32 type; /* Frame interval type the device supports. */ + + union { /* Frame interval */ + struct <link linkend="v4l2-fract">v4l2_fract</link> discrete; + struct <link linkend="v4l2-frmival-stepwise">v4l2_frmival_stepwise</link> stepwise; + }; + + __u32 reserved[2]; /* Reserved space for future use */ +}; +#endif + +/* + * T I M E C O D E + */ +struct <link linkend="v4l2-timecode">v4l2_timecode</link> { + __u32 type; + __u32 flags; + __u8 frames; + __u8 seconds; + __u8 minutes; + __u8 hours; + __u8 userbits[4]; +}; + +/* Type */ +#define V4L2_TC_TYPE_24FPS 1 +#define V4L2_TC_TYPE_25FPS 2 +#define V4L2_TC_TYPE_30FPS 3 +#define V4L2_TC_TYPE_50FPS 4 +#define V4L2_TC_TYPE_60FPS 5 + +/* Flags */ +#define V4L2_TC_FLAG_DROPFRAME 0x0001 /* "drop-frame" mode */ +#define V4L2_TC_FLAG_COLORFRAME 0x0002 +#define V4L2_TC_USERBITS_field 0x000C +#define V4L2_TC_USERBITS_USERDEFINED 0x0000 +#define V4L2_TC_USERBITS_8BITCHARS 0x0008 +/* The above is based on SMPTE timecodes */ + +struct <link linkend="v4l2-jpegcompression">v4l2_jpegcompression</link> { + int quality; + + int APPn; /* Number of APP segment to be written, + * must be 0..15 */ + int APP_len; /* Length of data in JPEG APPn segment */ + char APP_data[60]; /* Data in the JPEG APPn segment. */ + + int COM_len; /* Length of data in JPEG COM segment */ + char COM_data[60]; /* Data in JPEG COM segment */ + + __u32 jpeg_markers; /* Which markers should go into the JPEG + * output. Unless you exactly know what + * you do, leave them untouched. + * Inluding less markers will make the + * resulting code smaller, but there will + * be fewer aplications which can read it. + * The presence of the APP and COM marker + * is influenced by APP_len and COM_len + * ONLY, not by this property! */ + +#define V4L2_JPEG_MARKER_DHT (1<<3) /* Define Huffman Tables */ +#define V4L2_JPEG_MARKER_DQT (1<<4) /* Define Quantization Tables */ +#define V4L2_JPEG_MARKER_DRI (1<<5) /* Define Restart Interval */ +#define V4L2_JPEG_MARKER_COM (1<<6) /* Comment segment */ +#define V4L2_JPEG_MARKER_APP (1<<7) /* App segment, driver will + * allways use APP0 */ +}; + +/* + * M E M O R Y - M A P P I N G B U F F E R S + */ +struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> { + __u32 count; + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + enum <link linkend="v4l2-memory">v4l2_memory</link> memory; + __u32 reserved[2]; +}; + +struct <link linkend="v4l2-buffer">v4l2_buffer</link> { + __u32 index; + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + __u32 bytesused; + __u32 flags; + enum <link linkend="v4l2-field">v4l2_field</link> field; + struct timeval timestamp; + struct <link linkend="v4l2-timecode">v4l2_timecode</link> timecode; + __u32 sequence; + + /* memory location */ + enum <link linkend="v4l2-memory">v4l2_memory</link> memory; + union { + __u32 offset; + unsigned long userptr; + } m; + __u32 length; + __u32 input; + __u32 reserved; +}; + +/* Flags for 'flags' field */ +#define V4L2_BUF_FLAG_MAPPED 0x0001 /* Buffer is mapped (flag) */ +#define V4L2_BUF_FLAG_QUEUED 0x0002 /* Buffer is queued for processing */ +#define V4L2_BUF_FLAG_DONE 0x0004 /* Buffer is ready */ +#define V4L2_BUF_FLAG_KEYFRAME 0x0008 /* Image is a keyframe (I-frame) */ +#define V4L2_BUF_FLAG_PFRAME 0x0010 /* Image is a P-frame */ +#define V4L2_BUF_FLAG_BFRAME 0x0020 /* Image is a B-frame */ +#define V4L2_BUF_FLAG_TIMECODE 0x0100 /* timecode field is valid */ +#define V4L2_BUF_FLAG_INPUT 0x0200 /* input field is valid */ + +/* + * O V E R L A Y P R E V I E W + */ +struct <link linkend="v4l2-framebuffer">v4l2_framebuffer</link> { + __u32 capability; + __u32 flags; +/* FIXME: in theory we should pass something like PCI device + memory + * region + offset instead of some physical address */ + void *base; + struct <link linkend="v4l2-pix-format">v4l2_pix_format</link> fmt; +}; +/* Flags for the 'capability' field. Read only */ +#define V4L2_FBUF_CAP_EXTERNOVERLAY 0x0001 +#define V4L2_FBUF_CAP_CHROMAKEY 0x0002 +#define V4L2_FBUF_CAP_LIST_CLIPPING 0x0004 +#define V4L2_FBUF_CAP_BITMAP_CLIPPING 0x0008 +#define V4L2_FBUF_CAP_LOCAL_ALPHA 0x0010 +#define V4L2_FBUF_CAP_GLOBAL_ALPHA 0x0020 +#define V4L2_FBUF_CAP_LOCAL_INV_ALPHA 0x0040 +/* Flags for the 'flags' field. */ +#define V4L2_FBUF_FLAG_PRIMARY 0x0001 +#define V4L2_FBUF_FLAG_OVERLAY 0x0002 +#define V4L2_FBUF_FLAG_CHROMAKEY 0x0004 +#define V4L2_FBUF_FLAG_LOCAL_ALPHA 0x0008 +#define V4L2_FBUF_FLAG_GLOBAL_ALPHA 0x0010 +#define V4L2_FBUF_FLAG_LOCAL_INV_ALPHA 0x0020 + +struct <link linkend="v4l2-clip">v4l2_clip</link> { + struct <link linkend="v4l2-rect">v4l2_rect</link> c; + struct <link linkend="v4l2-clip">v4l2_clip</link> __user *next; +}; + +struct <link linkend="v4l2-window">v4l2_window</link> { + struct <link linkend="v4l2-rect">v4l2_rect</link> w; + enum <link linkend="v4l2-field">v4l2_field</link> field; + __u32 chromakey; + struct <link linkend="v4l2-clip">v4l2_clip</link> __user *clips; + __u32 clipcount; + void __user *bitmap; + __u8 global_alpha; +}; + +/* + * C A P T U R E P A R A M E T E R S + */ +struct <link linkend="v4l2-captureparm">v4l2_captureparm</link> { + __u32 capability; /* Supported modes */ + __u32 capturemode; /* Current mode */ + struct <link linkend="v4l2-fract">v4l2_fract</link> timeperframe; /* Time per frame in .1us units */ + __u32 extendedmode; /* Driver-specific extensions */ + __u32 readbuffers; /* # of buffers for read */ + __u32 reserved[4]; +}; + +/* Flags for 'capability' and 'capturemode' fields */ +#define V4L2_MODE_HIGHQUALITY 0x0001 /* High quality imaging mode */ +#define V4L2_CAP_TIMEPERFRAME 0x1000 /* timeperframe field is supported */ + +struct <link linkend="v4l2-outputparm">v4l2_outputparm</link> { + __u32 capability; /* Supported modes */ + __u32 outputmode; /* Current mode */ + struct <link linkend="v4l2-fract">v4l2_fract</link> timeperframe; /* Time per frame in seconds */ + __u32 extendedmode; /* Driver-specific extensions */ + __u32 writebuffers; /* # of buffers for write */ + __u32 reserved[4]; +}; + +/* + * I N P U T I M A G E C R O P P I N G + */ +struct <link linkend="v4l2-cropcap">v4l2_cropcap</link> { + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + struct <link linkend="v4l2-rect">v4l2_rect</link> bounds; + struct <link linkend="v4l2-rect">v4l2_rect</link> defrect; + struct <link linkend="v4l2-fract">v4l2_fract</link> pixelaspect; +}; + +struct <link linkend="v4l2-crop">v4l2_crop</link> { + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + struct <link linkend="v4l2-rect">v4l2_rect</link> c; +}; + +/* + * A N A L O G V I D E O S T A N D A R D + */ + +typedef __u64 v4l2_std_id; + +/* one bit for each */ +#define V4L2_STD_PAL_B ((v4l2_std_id)0x00000001) +#define V4L2_STD_PAL_B1 ((v4l2_std_id)0x00000002) +#define V4L2_STD_PAL_G ((v4l2_std_id)0x00000004) +#define V4L2_STD_PAL_H ((v4l2_std_id)0x00000008) +#define V4L2_STD_PAL_I ((v4l2_std_id)0x00000010) +#define V4L2_STD_PAL_D ((v4l2_std_id)0x00000020) +#define V4L2_STD_PAL_D1 ((v4l2_std_id)0x00000040) +#define V4L2_STD_PAL_K ((v4l2_std_id)0x00000080) + +#define V4L2_STD_PAL_M ((v4l2_std_id)0x00000100) +#define V4L2_STD_PAL_N ((v4l2_std_id)0x00000200) +#define V4L2_STD_PAL_Nc ((v4l2_std_id)0x00000400) +#define V4L2_STD_PAL_60 ((v4l2_std_id)0x00000800) + +#define V4L2_STD_NTSC_M ((v4l2_std_id)0x00001000) +#define V4L2_STD_NTSC_M_JP ((v4l2_std_id)0x00002000) +#define V4L2_STD_NTSC_443 ((v4l2_std_id)0x00004000) +#define V4L2_STD_NTSC_M_KR ((v4l2_std_id)0x00008000) + +#define V4L2_STD_SECAM_B ((v4l2_std_id)0x00010000) +#define V4L2_STD_SECAM_D ((v4l2_std_id)0x00020000) +#define V4L2_STD_SECAM_G ((v4l2_std_id)0x00040000) +#define V4L2_STD_SECAM_H ((v4l2_std_id)0x00080000) +#define V4L2_STD_SECAM_K ((v4l2_std_id)0x00100000) +#define V4L2_STD_SECAM_K1 ((v4l2_std_id)0x00200000) +#define V4L2_STD_SECAM_L ((v4l2_std_id)0x00400000) +#define V4L2_STD_SECAM_LC ((v4l2_std_id)0x00800000) + +/* ATSC/HDTV */ +#define V4L2_STD_ATSC_8_VSB ((v4l2_std_id)0x01000000) +#define V4L2_STD_ATSC_16_VSB ((v4l2_std_id)0x02000000) + +/* FIXME: + Although std_id is 64 bits, there is an issue on PPC32 architecture that + makes switch(__u64) to break. So, there's a hack on v4l2-common.c rounding + this value to 32 bits. + As, currently, the max value is for V4L2_STD_ATSC_16_VSB (30 bits wide), + it should work fine. However, if needed to add more than two standards, + v4l2-common.c should be fixed. + */ + +/* some merged standards */ +#define V4L2_STD_MN (V4L2_STD_PAL_M|V4L2_STD_PAL_N|V4L2_STD_PAL_Nc|V4L2_STD_NTSC) +#define V4L2_STD_B (V4L2_STD_PAL_B|V4L2_STD_PAL_B1|V4L2_STD_SECAM_B) +#define V4L2_STD_GH (V4L2_STD_PAL_G|V4L2_STD_PAL_H|V4L2_STD_SECAM_G|V4L2_STD_SECAM_H) +#define V4L2_STD_DK (V4L2_STD_PAL_DK|V4L2_STD_SECAM_DK) + +/* some common needed stuff */ +#define V4L2_STD_PAL_BG (V4L2_STD_PAL_B |\ + V4L2_STD_PAL_B1 |\ + V4L2_STD_PAL_G) +#define V4L2_STD_PAL_DK (V4L2_STD_PAL_D |\ + V4L2_STD_PAL_D1 |\ + V4L2_STD_PAL_K) +#define V4L2_STD_PAL (V4L2_STD_PAL_BG |\ + V4L2_STD_PAL_DK |\ + V4L2_STD_PAL_H |\ + V4L2_STD_PAL_I) +#define V4L2_STD_NTSC (V4L2_STD_NTSC_M |\ + V4L2_STD_NTSC_M_JP |\ + V4L2_STD_NTSC_M_KR) +#define V4L2_STD_SECAM_DK (V4L2_STD_SECAM_D |\ + V4L2_STD_SECAM_K |\ + V4L2_STD_SECAM_K1) +#define V4L2_STD_SECAM (V4L2_STD_SECAM_B |\ + V4L2_STD_SECAM_G |\ + V4L2_STD_SECAM_H |\ + V4L2_STD_SECAM_DK |\ + V4L2_STD_SECAM_L |\ + V4L2_STD_SECAM_LC) + +#define V4L2_STD_525_60 (V4L2_STD_PAL_M |\ + V4L2_STD_PAL_60 |\ + V4L2_STD_NTSC |\ + V4L2_STD_NTSC_443) +#define V4L2_STD_625_50 (V4L2_STD_PAL |\ + V4L2_STD_PAL_N |\ + V4L2_STD_PAL_Nc |\ + V4L2_STD_SECAM) +#define V4L2_STD_ATSC (V4L2_STD_ATSC_8_VSB |\ + V4L2_STD_ATSC_16_VSB) + +#define V4L2_STD_UNKNOWN 0 +#define V4L2_STD_ALL (V4L2_STD_525_60 |\ + V4L2_STD_625_50) + +struct <link linkend="v4l2-standard">v4l2_standard</link> { + __u32 index; + v4l2_std_id id; + __u8 name[24]; + struct <link linkend="v4l2-fract">v4l2_fract</link> frameperiod; /* Frames, not fields */ + __u32 framelines; + __u32 reserved[4]; +}; + +/* + * V I D E O I N P U T S + */ +struct <link linkend="v4l2-input">v4l2_input</link> { + __u32 index; /* Which input */ + __u8 name[32]; /* Label */ + __u32 type; /* Type of input */ + __u32 audioset; /* Associated audios (bitfield) */ + __u32 tuner; /* Associated tuner */ + v4l2_std_id std; + __u32 status; + __u32 reserved[4]; +}; + +/* Values for the 'type' field */ +#define V4L2_INPUT_TYPE_TUNER 1 +#define V4L2_INPUT_TYPE_CAMERA 2 + +/* field 'status' - general */ +#define V4L2_IN_ST_NO_POWER 0x00000001 /* Attached device is off */ +#define V4L2_IN_ST_NO_SIGNAL 0x00000002 +#define V4L2_IN_ST_NO_COLOR 0x00000004 + +/* field 'status' - sensor orientation */ +/* If sensor is mounted upside down set both bits */ +#define V4L2_IN_ST_HFLIP 0x00000010 /* Frames are flipped horizontally */ +#define V4L2_IN_ST_VFLIP 0x00000020 /* Frames are flipped vertically */ + +/* field 'status' - analog */ +#define V4L2_IN_ST_NO_H_LOCK 0x00000100 /* No horizontal sync lock */ +#define V4L2_IN_ST_COLOR_KILL 0x00000200 /* Color killer is active */ + +/* field 'status' - digital */ +#define V4L2_IN_ST_NO_SYNC 0x00010000 /* No synchronization lock */ +#define V4L2_IN_ST_NO_EQU 0x00020000 /* No equalizer lock */ +#define V4L2_IN_ST_NO_CARRIER 0x00040000 /* Carrier recovery failed */ + +/* field 'status' - VCR and set-top box */ +#define V4L2_IN_ST_MACROVISION 0x01000000 /* Macrovision detected */ +#define V4L2_IN_ST_NO_ACCESS 0x02000000 /* Conditional access denied */ +#define V4L2_IN_ST_VTR 0x04000000 /* VTR time constant */ + +/* + * V I D E O O U T P U T S + */ +struct <link linkend="v4l2-output">v4l2_output</link> { + __u32 index; /* Which output */ + __u8 name[32]; /* Label */ + __u32 type; /* Type of output */ + __u32 audioset; /* Associated audios (bitfield) */ + __u32 modulator; /* Associated modulator */ + v4l2_std_id std; + __u32 reserved[4]; +}; +/* Values for the 'type' field */ +#define V4L2_OUTPUT_TYPE_MODULATOR 1 +#define V4L2_OUTPUT_TYPE_ANALOG 2 +#define V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY 3 + +/* + * C O N T R O L S + */ +struct <link linkend="v4l2-control">v4l2_control</link> { + __u32 id; + __s32 value; +}; + +struct <link linkend="v4l2-ext-control">v4l2_ext_control</link> { + __u32 id; + __u32 size; + __u32 reserved2[1]; + union { + __s32 value; + __s64 value64; + char *string; + }; +} __attribute__ ((packed)); + +struct <link linkend="v4l2-ext-controls">v4l2_ext_controls</link> { + __u32 ctrl_class; + __u32 count; + __u32 error_idx; + __u32 reserved[2]; + struct <link linkend="v4l2-ext-control">v4l2_ext_control</link> *controls; +}; + +/* Values for ctrl_class field */ +#define V4L2_CTRL_CLASS_USER 0x00980000 /* Old-style 'user' controls */ +#define V4L2_CTRL_CLASS_MPEG 0x00990000 /* MPEG-compression controls */ +#define V4L2_CTRL_CLASS_CAMERA 0x009a0000 /* Camera class controls */ +#define V4L2_CTRL_CLASS_FM_TX 0x009b0000 /* FM Modulator control class */ + +#define V4L2_CTRL_ID_MASK (0x0fffffff) +#define V4L2_CTRL_ID2CLASS(id) ((id) & 0x0fff0000UL) +#define V4L2_CTRL_DRIVER_PRIV(id) (((id) & 0xffff) >= 0x1000) + +/* Used in the VIDIOC_QUERYCTRL ioctl for querying controls */ +struct <link linkend="v4l2-queryctrl">v4l2_queryctrl</link> { + __u32 id; + enum <link linkend="v4l2-ctrl-type">v4l2_ctrl_type</link> type; + __u8 name[32]; /* Whatever */ + __s32 minimum; /* Note signedness */ + __s32 maximum; + __s32 step; + __s32 default_value; + __u32 flags; + __u32 reserved[2]; +}; + +/* Used in the VIDIOC_QUERYMENU ioctl for querying menu items */ +struct <link linkend="v4l2-querymenu">v4l2_querymenu</link> { + __u32 id; + __u32 index; + __u8 name[32]; /* Whatever */ + __u32 reserved; +}; + +/* Control flags */ +#define V4L2_CTRL_FLAG_DISABLED 0x0001 +#define V4L2_CTRL_FLAG_GRABBED 0x0002 +#define V4L2_CTRL_FLAG_READ_ONLY 0x0004 +#define V4L2_CTRL_FLAG_UPDATE 0x0008 +#define V4L2_CTRL_FLAG_INACTIVE 0x0010 +#define V4L2_CTRL_FLAG_SLIDER 0x0020 +#define V4L2_CTRL_FLAG_WRITE_ONLY 0x0040 + +/* Query flag, to be ORed with the control ID */ +#define V4L2_CTRL_FLAG_NEXT_CTRL 0x80000000 + +/* User-class control IDs defined by V4L2 */ +#define V4L2_CID_BASE (V4L2_CTRL_CLASS_USER | 0x900) +#define V4L2_CID_USER_BASE V4L2_CID_BASE +/* IDs reserved for driver specific controls */ +#define V4L2_CID_PRIVATE_BASE 0x08000000 + +#define V4L2_CID_USER_CLASS (V4L2_CTRL_CLASS_USER | 1) +#define V4L2_CID_BRIGHTNESS (V4L2_CID_BASE+0) +#define V4L2_CID_CONTRAST (V4L2_CID_BASE+1) +#define V4L2_CID_SATURATION (V4L2_CID_BASE+2) +#define V4L2_CID_HUE (V4L2_CID_BASE+3) +#define V4L2_CID_AUDIO_VOLUME (V4L2_CID_BASE+5) +#define V4L2_CID_AUDIO_BALANCE (V4L2_CID_BASE+6) +#define V4L2_CID_AUDIO_BASS (V4L2_CID_BASE+7) +#define V4L2_CID_AUDIO_TREBLE (V4L2_CID_BASE+8) +#define V4L2_CID_AUDIO_MUTE (V4L2_CID_BASE+9) +#define V4L2_CID_AUDIO_LOUDNESS (V4L2_CID_BASE+10) +#define V4L2_CID_BLACK_LEVEL (V4L2_CID_BASE+11) /* Deprecated */ +#define V4L2_CID_AUTO_WHITE_BALANCE (V4L2_CID_BASE+12) +#define V4L2_CID_DO_WHITE_BALANCE (V4L2_CID_BASE+13) +#define V4L2_CID_RED_BALANCE (V4L2_CID_BASE+14) +#define V4L2_CID_BLUE_BALANCE (V4L2_CID_BASE+15) +#define V4L2_CID_GAMMA (V4L2_CID_BASE+16) +#define V4L2_CID_WHITENESS (V4L2_CID_GAMMA) /* Deprecated */ +#define V4L2_CID_EXPOSURE (V4L2_CID_BASE+17) +#define V4L2_CID_AUTOGAIN (V4L2_CID_BASE+18) +#define V4L2_CID_GAIN (V4L2_CID_BASE+19) +#define V4L2_CID_HFLIP (V4L2_CID_BASE+20) +#define V4L2_CID_VFLIP (V4L2_CID_BASE+21) + +/* Deprecated; use V4L2_CID_PAN_RESET and V4L2_CID_TILT_RESET */ +#define V4L2_CID_HCENTER (V4L2_CID_BASE+22) +#define V4L2_CID_VCENTER (V4L2_CID_BASE+23) + +#define V4L2_CID_POWER_LINE_FREQUENCY (V4L2_CID_BASE+24) +enum <link linkend="v4l2-power-line-frequency">v4l2_power_line_frequency</link> { + V4L2_CID_POWER_LINE_FREQUENCY_DISABLED = 0, + V4L2_CID_POWER_LINE_FREQUENCY_50HZ = 1, + V4L2_CID_POWER_LINE_FREQUENCY_60HZ = 2, +}; +#define V4L2_CID_HUE_AUTO (V4L2_CID_BASE+25) +#define V4L2_CID_WHITE_BALANCE_TEMPERATURE (V4L2_CID_BASE+26) +#define V4L2_CID_SHARPNESS (V4L2_CID_BASE+27) +#define V4L2_CID_BACKLIGHT_COMPENSATION (V4L2_CID_BASE+28) +#define V4L2_CID_CHROMA_AGC (V4L2_CID_BASE+29) +#define V4L2_CID_COLOR_KILLER (V4L2_CID_BASE+30) +#define V4L2_CID_COLORFX (V4L2_CID_BASE+31) +enum <link linkend="v4l2-colorfx">v4l2_colorfx</link> { + V4L2_COLORFX_NONE = 0, + V4L2_COLORFX_BW = 1, + V4L2_COLORFX_SEPIA = 2, +}; +#define V4L2_CID_AUTOBRIGHTNESS (V4L2_CID_BASE+32) +#define V4L2_CID_BAND_STOP_FILTER (V4L2_CID_BASE+33) + +/* last CID + 1 */ +#define V4L2_CID_LASTP1 (V4L2_CID_BASE+34) + +/* MPEG-class control IDs defined by V4L2 */ +#define V4L2_CID_MPEG_BASE (V4L2_CTRL_CLASS_MPEG | 0x900) +#define V4L2_CID_MPEG_CLASS (V4L2_CTRL_CLASS_MPEG | 1) + +/* MPEG streams */ +#define V4L2_CID_MPEG_STREAM_TYPE (V4L2_CID_MPEG_BASE+0) +enum <link linkend="v4l2-mpeg-stream-type">v4l2_mpeg_stream_type</link> { + V4L2_MPEG_STREAM_TYPE_MPEG2_PS = 0, /* MPEG-2 program stream */ + V4L2_MPEG_STREAM_TYPE_MPEG2_TS = 1, /* MPEG-2 transport stream */ + V4L2_MPEG_STREAM_TYPE_MPEG1_SS = 2, /* MPEG-1 system stream */ + V4L2_MPEG_STREAM_TYPE_MPEG2_DVD = 3, /* MPEG-2 DVD-compatible stream */ + V4L2_MPEG_STREAM_TYPE_MPEG1_VCD = 4, /* MPEG-1 VCD-compatible stream */ + V4L2_MPEG_STREAM_TYPE_MPEG2_SVCD = 5, /* MPEG-2 SVCD-compatible stream */ +}; +#define V4L2_CID_MPEG_STREAM_PID_PMT (V4L2_CID_MPEG_BASE+1) +#define V4L2_CID_MPEG_STREAM_PID_AUDIO (V4L2_CID_MPEG_BASE+2) +#define V4L2_CID_MPEG_STREAM_PID_VIDEO (V4L2_CID_MPEG_BASE+3) +#define V4L2_CID_MPEG_STREAM_PID_PCR (V4L2_CID_MPEG_BASE+4) +#define V4L2_CID_MPEG_STREAM_PES_ID_AUDIO (V4L2_CID_MPEG_BASE+5) +#define V4L2_CID_MPEG_STREAM_PES_ID_VIDEO (V4L2_CID_MPEG_BASE+6) +#define V4L2_CID_MPEG_STREAM_VBI_FMT (V4L2_CID_MPEG_BASE+7) +enum <link linkend="v4l2-mpeg-stream-vbi-fmt">v4l2_mpeg_stream_vbi_fmt</link> { + V4L2_MPEG_STREAM_VBI_FMT_NONE = 0, /* No VBI in the MPEG stream */ + V4L2_MPEG_STREAM_VBI_FMT_IVTV = 1, /* VBI in private packets, IVTV format */ +}; + +/* MPEG audio */ +#define V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ (V4L2_CID_MPEG_BASE+100) +enum <link linkend="v4l2-mpeg-audio-sampling-freq">v4l2_mpeg_audio_sampling_freq</link> { + V4L2_MPEG_AUDIO_SAMPLING_FREQ_44100 = 0, + V4L2_MPEG_AUDIO_SAMPLING_FREQ_48000 = 1, + V4L2_MPEG_AUDIO_SAMPLING_FREQ_32000 = 2, +}; +#define V4L2_CID_MPEG_AUDIO_ENCODING (V4L2_CID_MPEG_BASE+101) +enum <link linkend="v4l2-mpeg-audio-encoding">v4l2_mpeg_audio_encoding</link> { + V4L2_MPEG_AUDIO_ENCODING_LAYER_1 = 0, + V4L2_MPEG_AUDIO_ENCODING_LAYER_2 = 1, + V4L2_MPEG_AUDIO_ENCODING_LAYER_3 = 2, + V4L2_MPEG_AUDIO_ENCODING_AAC = 3, + V4L2_MPEG_AUDIO_ENCODING_AC3 = 4, +}; +#define V4L2_CID_MPEG_AUDIO_L1_BITRATE (V4L2_CID_MPEG_BASE+102) +enum <link linkend="v4l2-mpeg-audio-l1-bitrate">v4l2_mpeg_audio_l1_bitrate</link> { + V4L2_MPEG_AUDIO_L1_BITRATE_32K = 0, + V4L2_MPEG_AUDIO_L1_BITRATE_64K = 1, + V4L2_MPEG_AUDIO_L1_BITRATE_96K = 2, + V4L2_MPEG_AUDIO_L1_BITRATE_128K = 3, + V4L2_MPEG_AUDIO_L1_BITRATE_160K = 4, + V4L2_MPEG_AUDIO_L1_BITRATE_192K = 5, + V4L2_MPEG_AUDIO_L1_BITRATE_224K = 6, + V4L2_MPEG_AUDIO_L1_BITRATE_256K = 7, + V4L2_MPEG_AUDIO_L1_BITRATE_288K = 8, + V4L2_MPEG_AUDIO_L1_BITRATE_320K = 9, + V4L2_MPEG_AUDIO_L1_BITRATE_352K = 10, + V4L2_MPEG_AUDIO_L1_BITRATE_384K = 11, + V4L2_MPEG_AUDIO_L1_BITRATE_416K = 12, + V4L2_MPEG_AUDIO_L1_BITRATE_448K = 13, +}; +#define V4L2_CID_MPEG_AUDIO_L2_BITRATE (V4L2_CID_MPEG_BASE+103) +enum <link linkend="v4l2-mpeg-audio-l2-bitrate">v4l2_mpeg_audio_l2_bitrate</link> { + V4L2_MPEG_AUDIO_L2_BITRATE_32K = 0, + V4L2_MPEG_AUDIO_L2_BITRATE_48K = 1, + V4L2_MPEG_AUDIO_L2_BITRATE_56K = 2, + V4L2_MPEG_AUDIO_L2_BITRATE_64K = 3, + V4L2_MPEG_AUDIO_L2_BITRATE_80K = 4, + V4L2_MPEG_AUDIO_L2_BITRATE_96K = 5, + V4L2_MPEG_AUDIO_L2_BITRATE_112K = 6, + V4L2_MPEG_AUDIO_L2_BITRATE_128K = 7, + V4L2_MPEG_AUDIO_L2_BITRATE_160K = 8, + V4L2_MPEG_AUDIO_L2_BITRATE_192K = 9, + V4L2_MPEG_AUDIO_L2_BITRATE_224K = 10, + V4L2_MPEG_AUDIO_L2_BITRATE_256K = 11, + V4L2_MPEG_AUDIO_L2_BITRATE_320K = 12, + V4L2_MPEG_AUDIO_L2_BITRATE_384K = 13, +}; +#define V4L2_CID_MPEG_AUDIO_L3_BITRATE (V4L2_CID_MPEG_BASE+104) +enum <link linkend="v4l2-mpeg-audio-l3-bitrate">v4l2_mpeg_audio_l3_bitrate</link> { + V4L2_MPEG_AUDIO_L3_BITRATE_32K = 0, + V4L2_MPEG_AUDIO_L3_BITRATE_40K = 1, + V4L2_MPEG_AUDIO_L3_BITRATE_48K = 2, + V4L2_MPEG_AUDIO_L3_BITRATE_56K = 3, + V4L2_MPEG_AUDIO_L3_BITRATE_64K = 4, + V4L2_MPEG_AUDIO_L3_BITRATE_80K = 5, + V4L2_MPEG_AUDIO_L3_BITRATE_96K = 6, + V4L2_MPEG_AUDIO_L3_BITRATE_112K = 7, + V4L2_MPEG_AUDIO_L3_BITRATE_128K = 8, + V4L2_MPEG_AUDIO_L3_BITRATE_160K = 9, + V4L2_MPEG_AUDIO_L3_BITRATE_192K = 10, + V4L2_MPEG_AUDIO_L3_BITRATE_224K = 11, + V4L2_MPEG_AUDIO_L3_BITRATE_256K = 12, + V4L2_MPEG_AUDIO_L3_BITRATE_320K = 13, +}; +#define V4L2_CID_MPEG_AUDIO_MODE (V4L2_CID_MPEG_BASE+105) +enum <link linkend="v4l2-mpeg-audio-mode">v4l2_mpeg_audio_mode</link> { + V4L2_MPEG_AUDIO_MODE_STEREO = 0, + V4L2_MPEG_AUDIO_MODE_JOINT_STEREO = 1, + V4L2_MPEG_AUDIO_MODE_DUAL = 2, + V4L2_MPEG_AUDIO_MODE_MONO = 3, +}; +#define V4L2_CID_MPEG_AUDIO_MODE_EXTENSION (V4L2_CID_MPEG_BASE+106) +enum <link linkend="v4l2-mpeg-audio-mode-extension">v4l2_mpeg_audio_mode_extension</link> { + V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_4 = 0, + V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_8 = 1, + V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_12 = 2, + V4L2_MPEG_AUDIO_MODE_EXTENSION_BOUND_16 = 3, +}; +#define V4L2_CID_MPEG_AUDIO_EMPHASIS (V4L2_CID_MPEG_BASE+107) +enum <link linkend="v4l2-mpeg-audio-emphasis">v4l2_mpeg_audio_emphasis</link> { + V4L2_MPEG_AUDIO_EMPHASIS_NONE = 0, + V4L2_MPEG_AUDIO_EMPHASIS_50_DIV_15_uS = 1, + V4L2_MPEG_AUDIO_EMPHASIS_CCITT_J17 = 2, +}; +#define V4L2_CID_MPEG_AUDIO_CRC (V4L2_CID_MPEG_BASE+108) +enum <link linkend="v4l2-mpeg-audio-crc">v4l2_mpeg_audio_crc</link> { + V4L2_MPEG_AUDIO_CRC_NONE = 0, + V4L2_MPEG_AUDIO_CRC_CRC16 = 1, +}; +#define V4L2_CID_MPEG_AUDIO_MUTE (V4L2_CID_MPEG_BASE+109) +#define V4L2_CID_MPEG_AUDIO_AAC_BITRATE (V4L2_CID_MPEG_BASE+110) +#define V4L2_CID_MPEG_AUDIO_AC3_BITRATE (V4L2_CID_MPEG_BASE+111) +enum <link linkend="v4l2-mpeg-audio-ac3-bitrate">v4l2_mpeg_audio_ac3_bitrate</link> { + V4L2_MPEG_AUDIO_AC3_BITRATE_32K = 0, + V4L2_MPEG_AUDIO_AC3_BITRATE_40K = 1, + V4L2_MPEG_AUDIO_AC3_BITRATE_48K = 2, + V4L2_MPEG_AUDIO_AC3_BITRATE_56K = 3, + V4L2_MPEG_AUDIO_AC3_BITRATE_64K = 4, + V4L2_MPEG_AUDIO_AC3_BITRATE_80K = 5, + V4L2_MPEG_AUDIO_AC3_BITRATE_96K = 6, + V4L2_MPEG_AUDIO_AC3_BITRATE_112K = 7, + V4L2_MPEG_AUDIO_AC3_BITRATE_128K = 8, + V4L2_MPEG_AUDIO_AC3_BITRATE_160K = 9, + V4L2_MPEG_AUDIO_AC3_BITRATE_192K = 10, + V4L2_MPEG_AUDIO_AC3_BITRATE_224K = 11, + V4L2_MPEG_AUDIO_AC3_BITRATE_256K = 12, + V4L2_MPEG_AUDIO_AC3_BITRATE_320K = 13, + V4L2_MPEG_AUDIO_AC3_BITRATE_384K = 14, + V4L2_MPEG_AUDIO_AC3_BITRATE_448K = 15, + V4L2_MPEG_AUDIO_AC3_BITRATE_512K = 16, + V4L2_MPEG_AUDIO_AC3_BITRATE_576K = 17, + V4L2_MPEG_AUDIO_AC3_BITRATE_640K = 18, +}; + +/* MPEG video */ +#define V4L2_CID_MPEG_VIDEO_ENCODING (V4L2_CID_MPEG_BASE+200) +enum <link linkend="v4l2-mpeg-video-encoding">v4l2_mpeg_video_encoding</link> { + V4L2_MPEG_VIDEO_ENCODING_MPEG_1 = 0, + V4L2_MPEG_VIDEO_ENCODING_MPEG_2 = 1, + V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC = 2, +}; +#define V4L2_CID_MPEG_VIDEO_ASPECT (V4L2_CID_MPEG_BASE+201) +enum <link linkend="v4l2-mpeg-video-aspect">v4l2_mpeg_video_aspect</link> { + V4L2_MPEG_VIDEO_ASPECT_1x1 = 0, + V4L2_MPEG_VIDEO_ASPECT_4x3 = 1, + V4L2_MPEG_VIDEO_ASPECT_16x9 = 2, + V4L2_MPEG_VIDEO_ASPECT_221x100 = 3, +}; +#define V4L2_CID_MPEG_VIDEO_B_FRAMES (V4L2_CID_MPEG_BASE+202) +#define V4L2_CID_MPEG_VIDEO_GOP_SIZE (V4L2_CID_MPEG_BASE+203) +#define V4L2_CID_MPEG_VIDEO_GOP_CLOSURE (V4L2_CID_MPEG_BASE+204) +#define V4L2_CID_MPEG_VIDEO_PULLDOWN (V4L2_CID_MPEG_BASE+205) +#define V4L2_CID_MPEG_VIDEO_BITRATE_MODE (V4L2_CID_MPEG_BASE+206) +enum <link linkend="v4l2-mpeg-video-bitrate-mode">v4l2_mpeg_video_bitrate_mode</link> { + V4L2_MPEG_VIDEO_BITRATE_MODE_VBR = 0, + V4L2_MPEG_VIDEO_BITRATE_MODE_CBR = 1, +}; +#define V4L2_CID_MPEG_VIDEO_BITRATE (V4L2_CID_MPEG_BASE+207) +#define V4L2_CID_MPEG_VIDEO_BITRATE_PEAK (V4L2_CID_MPEG_BASE+208) +#define V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION (V4L2_CID_MPEG_BASE+209) +#define V4L2_CID_MPEG_VIDEO_MUTE (V4L2_CID_MPEG_BASE+210) +#define V4L2_CID_MPEG_VIDEO_MUTE_YUV (V4L2_CID_MPEG_BASE+211) + +/* MPEG-class control IDs specific to the CX2341x driver as defined by V4L2 */ +#define V4L2_CID_MPEG_CX2341X_BASE (V4L2_CTRL_CLASS_MPEG | 0x1000) +#define V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE (V4L2_CID_MPEG_CX2341X_BASE+0) +enum <link linkend="v4l2-mpeg-cx2341x-video-spatial-filter-mode">v4l2_mpeg_cx2341x_video_spatial_filter_mode</link> { + V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_MANUAL = 0, + V4L2_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE_AUTO = 1, +}; +#define V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER (V4L2_CID_MPEG_CX2341X_BASE+1) +#define V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE (V4L2_CID_MPEG_CX2341X_BASE+2) +enum <link linkend="luma-spatial-filter-type">v4l2_mpeg_cx2341x_video_luma_spatial_filter_type</link> { + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_OFF = 0, + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_HOR = 1, + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_1D_VERT = 2, + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_HV_SEPARABLE = 3, + V4L2_MPEG_CX2341X_VIDEO_LUMA_SPATIAL_FILTER_TYPE_2D_SYM_NON_SEPARABLE = 4, +}; +#define V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE (V4L2_CID_MPEG_CX2341X_BASE+3) +enum <link linkend="chroma-spatial-filter-type">v4l2_mpeg_cx2341x_video_chroma_spatial_filter_type</link> { + V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_OFF = 0, + V4L2_MPEG_CX2341X_VIDEO_CHROMA_SPATIAL_FILTER_TYPE_1D_HOR = 1, +}; +#define V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE (V4L2_CID_MPEG_CX2341X_BASE+4) +enum <link linkend="v4l2-mpeg-cx2341x-video-temporal-filter-mode">v4l2_mpeg_cx2341x_video_temporal_filter_mode</link> { + V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_MANUAL = 0, + V4L2_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER_MODE_AUTO = 1, +}; +#define V4L2_CID_MPEG_CX2341X_VIDEO_TEMPORAL_FILTER (V4L2_CID_MPEG_CX2341X_BASE+5) +#define V4L2_CID_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE (V4L2_CID_MPEG_CX2341X_BASE+6) +enum <link linkend="v4l2-mpeg-cx2341x-video-median-filter-type">v4l2_mpeg_cx2341x_video_median_filter_type</link> { + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_OFF = 0, + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR = 1, + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_VERT = 2, + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_HOR_VERT = 3, + V4L2_MPEG_CX2341X_VIDEO_MEDIAN_FILTER_TYPE_DIAG = 4, +}; +#define V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_BOTTOM (V4L2_CID_MPEG_CX2341X_BASE+7) +#define V4L2_CID_MPEG_CX2341X_VIDEO_LUMA_MEDIAN_FILTER_TOP (V4L2_CID_MPEG_CX2341X_BASE+8) +#define V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_BOTTOM (V4L2_CID_MPEG_CX2341X_BASE+9) +#define V4L2_CID_MPEG_CX2341X_VIDEO_CHROMA_MEDIAN_FILTER_TOP (V4L2_CID_MPEG_CX2341X_BASE+10) +#define V4L2_CID_MPEG_CX2341X_STREAM_INSERT_NAV_PACKETS (V4L2_CID_MPEG_CX2341X_BASE+11) + +/* Camera class control IDs */ +#define V4L2_CID_CAMERA_CLASS_BASE (V4L2_CTRL_CLASS_CAMERA | 0x900) +#define V4L2_CID_CAMERA_CLASS (V4L2_CTRL_CLASS_CAMERA | 1) + +#define V4L2_CID_EXPOSURE_AUTO (V4L2_CID_CAMERA_CLASS_BASE+1) +enum <link linkend="v4l2-exposure-auto-type">v4l2_exposure_auto_type</link> { + V4L2_EXPOSURE_AUTO = 0, + V4L2_EXPOSURE_MANUAL = 1, + V4L2_EXPOSURE_SHUTTER_PRIORITY = 2, + V4L2_EXPOSURE_APERTURE_PRIORITY = 3 +}; +#define V4L2_CID_EXPOSURE_ABSOLUTE (V4L2_CID_CAMERA_CLASS_BASE+2) +#define V4L2_CID_EXPOSURE_AUTO_PRIORITY (V4L2_CID_CAMERA_CLASS_BASE+3) + +#define V4L2_CID_PAN_RELATIVE (V4L2_CID_CAMERA_CLASS_BASE+4) +#define V4L2_CID_TILT_RELATIVE (V4L2_CID_CAMERA_CLASS_BASE+5) +#define V4L2_CID_PAN_RESET (V4L2_CID_CAMERA_CLASS_BASE+6) +#define V4L2_CID_TILT_RESET (V4L2_CID_CAMERA_CLASS_BASE+7) + +#define V4L2_CID_PAN_ABSOLUTE (V4L2_CID_CAMERA_CLASS_BASE+8) +#define V4L2_CID_TILT_ABSOLUTE (V4L2_CID_CAMERA_CLASS_BASE+9) + +#define V4L2_CID_FOCUS_ABSOLUTE (V4L2_CID_CAMERA_CLASS_BASE+10) +#define V4L2_CID_FOCUS_RELATIVE (V4L2_CID_CAMERA_CLASS_BASE+11) +#define V4L2_CID_FOCUS_AUTO (V4L2_CID_CAMERA_CLASS_BASE+12) + +#define V4L2_CID_ZOOM_ABSOLUTE (V4L2_CID_CAMERA_CLASS_BASE+13) +#define V4L2_CID_ZOOM_RELATIVE (V4L2_CID_CAMERA_CLASS_BASE+14) +#define V4L2_CID_ZOOM_CONTINUOUS (V4L2_CID_CAMERA_CLASS_BASE+15) + +#define V4L2_CID_PRIVACY (V4L2_CID_CAMERA_CLASS_BASE+16) + +/* FM Modulator class control IDs */ +#define V4L2_CID_FM_TX_CLASS_BASE (V4L2_CTRL_CLASS_FM_TX | 0x900) +#define V4L2_CID_FM_TX_CLASS (V4L2_CTRL_CLASS_FM_TX | 1) + +#define V4L2_CID_RDS_TX_DEVIATION (V4L2_CID_FM_TX_CLASS_BASE + 1) +#define V4L2_CID_RDS_TX_PI (V4L2_CID_FM_TX_CLASS_BASE + 2) +#define V4L2_CID_RDS_TX_PTY (V4L2_CID_FM_TX_CLASS_BASE + 3) +#define V4L2_CID_RDS_TX_PS_NAME (V4L2_CID_FM_TX_CLASS_BASE + 5) +#define V4L2_CID_RDS_TX_RADIO_TEXT (V4L2_CID_FM_TX_CLASS_BASE + 6) + +#define V4L2_CID_AUDIO_LIMITER_ENABLED (V4L2_CID_FM_TX_CLASS_BASE + 64) +#define V4L2_CID_AUDIO_LIMITER_RELEASE_TIME (V4L2_CID_FM_TX_CLASS_BASE + 65) +#define V4L2_CID_AUDIO_LIMITER_DEVIATION (V4L2_CID_FM_TX_CLASS_BASE + 66) + +#define V4L2_CID_AUDIO_COMPRESSION_ENABLED (V4L2_CID_FM_TX_CLASS_BASE + 80) +#define V4L2_CID_AUDIO_COMPRESSION_GAIN (V4L2_CID_FM_TX_CLASS_BASE + 81) +#define V4L2_CID_AUDIO_COMPRESSION_THRESHOLD (V4L2_CID_FM_TX_CLASS_BASE + 82) +#define V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME (V4L2_CID_FM_TX_CLASS_BASE + 83) +#define V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME (V4L2_CID_FM_TX_CLASS_BASE + 84) + +#define V4L2_CID_PILOT_TONE_ENABLED (V4L2_CID_FM_TX_CLASS_BASE + 96) +#define V4L2_CID_PILOT_TONE_DEVIATION (V4L2_CID_FM_TX_CLASS_BASE + 97) +#define V4L2_CID_PILOT_TONE_FREQUENCY (V4L2_CID_FM_TX_CLASS_BASE + 98) + +#define V4L2_CID_TUNE_PREEMPHASIS (V4L2_CID_FM_TX_CLASS_BASE + 112) +enum <link linkend="v4l2-preemphasis">v4l2_preemphasis</link> { + V4L2_PREEMPHASIS_DISABLED = 0, + V4L2_PREEMPHASIS_50_uS = 1, + V4L2_PREEMPHASIS_75_uS = 2, +}; +#define V4L2_CID_TUNE_POWER_LEVEL (V4L2_CID_FM_TX_CLASS_BASE + 113) +#define V4L2_CID_TUNE_ANTENNA_CAPACITOR (V4L2_CID_FM_TX_CLASS_BASE + 114) + +/* + * T U N I N G + */ +struct <link linkend="v4l2-tuner">v4l2_tuner</link> { + __u32 index; + __u8 name[32]; + enum <link linkend="v4l2-tuner-type">v4l2_tuner_type</link> type; + __u32 capability; + __u32 rangelow; + __u32 rangehigh; + __u32 rxsubchans; + __u32 audmode; + __s32 signal; + __s32 afc; + __u32 reserved[4]; +}; + +struct <link linkend="v4l2-modulator">v4l2_modulator</link> { + __u32 index; + __u8 name[32]; + __u32 capability; + __u32 rangelow; + __u32 rangehigh; + __u32 txsubchans; + __u32 reserved[4]; +}; + +/* Flags for the 'capability' field */ +#define V4L2_TUNER_CAP_LOW 0x0001 +#define V4L2_TUNER_CAP_NORM 0x0002 +#define V4L2_TUNER_CAP_STEREO 0x0010 +#define V4L2_TUNER_CAP_LANG2 0x0020 +#define V4L2_TUNER_CAP_SAP 0x0020 +#define V4L2_TUNER_CAP_LANG1 0x0040 +#define V4L2_TUNER_CAP_RDS 0x0080 + +/* Flags for the 'rxsubchans' field */ +#define V4L2_TUNER_SUB_MONO 0x0001 +#define V4L2_TUNER_SUB_STEREO 0x0002 +#define V4L2_TUNER_SUB_LANG2 0x0004 +#define V4L2_TUNER_SUB_SAP 0x0004 +#define V4L2_TUNER_SUB_LANG1 0x0008 +#define V4L2_TUNER_SUB_RDS 0x0010 + +/* Values for the 'audmode' field */ +#define V4L2_TUNER_MODE_MONO 0x0000 +#define V4L2_TUNER_MODE_STEREO 0x0001 +#define V4L2_TUNER_MODE_LANG2 0x0002 +#define V4L2_TUNER_MODE_SAP 0x0002 +#define V4L2_TUNER_MODE_LANG1 0x0003 +#define V4L2_TUNER_MODE_LANG1_LANG2 0x0004 + +struct <link linkend="v4l2-frequency">v4l2_frequency</link> { + __u32 tuner; + enum <link linkend="v4l2-tuner-type">v4l2_tuner_type</link> type; + __u32 frequency; + __u32 reserved[8]; +}; + +struct <link linkend="v4l2-hw-freq-seek">v4l2_hw_freq_seek</link> { + __u32 tuner; + enum <link linkend="v4l2-tuner-type">v4l2_tuner_type</link> type; + __u32 seek_upward; + __u32 wrap_around; + __u32 reserved[8]; +}; + +/* + * R D S + */ + +struct <link linkend="v4l2-rds-data">v4l2_rds_data</link> { + __u8 lsb; + __u8 msb; + __u8 block; +} __attribute__ ((packed)); + +#define V4L2_RDS_BLOCK_MSK 0x7 +#define V4L2_RDS_BLOCK_A 0 +#define V4L2_RDS_BLOCK_B 1 +#define V4L2_RDS_BLOCK_C 2 +#define V4L2_RDS_BLOCK_D 3 +#define V4L2_RDS_BLOCK_C_ALT 4 +#define V4L2_RDS_BLOCK_INVALID 7 + +#define V4L2_RDS_BLOCK_CORRECTED 0x40 +#define V4L2_RDS_BLOCK_ERROR 0x80 + +/* + * A U D I O + */ +struct <link linkend="v4l2-audio">v4l2_audio</link> { + __u32 index; + __u8 name[32]; + __u32 capability; + __u32 mode; + __u32 reserved[2]; +}; + +/* Flags for the 'capability' field */ +#define V4L2_AUDCAP_STEREO 0x00001 +#define V4L2_AUDCAP_AVL 0x00002 + +/* Flags for the 'mode' field */ +#define V4L2_AUDMODE_AVL 0x00001 + +struct <link linkend="v4l2-audioout">v4l2_audioout</link> { + __u32 index; + __u8 name[32]; + __u32 capability; + __u32 mode; + __u32 reserved[2]; +}; + +/* + * M P E G S E R V I C E S + * + * NOTE: EXPERIMENTAL API + */ +#if 1 /*KEEP*/ +#define V4L2_ENC_IDX_FRAME_I (0) +#define V4L2_ENC_IDX_FRAME_P (1) +#define V4L2_ENC_IDX_FRAME_B (2) +#define V4L2_ENC_IDX_FRAME_MASK (0xf) + +struct <link linkend="v4l2-enc-idx-entry">v4l2_enc_idx_entry</link> { + __u64 offset; + __u64 pts; + __u32 length; + __u32 flags; + __u32 reserved[2]; +}; + +#define V4L2_ENC_IDX_ENTRIES (64) +struct <link linkend="v4l2-enc-idx">v4l2_enc_idx</link> { + __u32 entries; + __u32 entries_cap; + __u32 reserved[4]; + struct <link linkend="v4l2-enc-idx-entry">v4l2_enc_idx_entry</link> entry[V4L2_ENC_IDX_ENTRIES]; +}; + + +#define V4L2_ENC_CMD_START (0) +#define V4L2_ENC_CMD_STOP (1) +#define V4L2_ENC_CMD_PAUSE (2) +#define V4L2_ENC_CMD_RESUME (3) + +/* Flags for V4L2_ENC_CMD_STOP */ +#define V4L2_ENC_CMD_STOP_AT_GOP_END (1 << 0) + +struct <link linkend="v4l2-encoder-cmd">v4l2_encoder_cmd</link> { + __u32 cmd; + __u32 flags; + union { + struct { + __u32 data[8]; + } raw; + }; +}; + +#endif + + +/* + * D A T A S E R V I C E S ( V B I ) + * + * Data services API by Michael Schimek + */ + +/* Raw VBI */ +struct <link linkend="v4l2-vbi-format">v4l2_vbi_format</link> { + __u32 sampling_rate; /* in 1 Hz */ + __u32 offset; + __u32 samples_per_line; + __u32 sample_format; /* V4L2_PIX_FMT_* */ + __s32 start[2]; + __u32 count[2]; + __u32 flags; /* V4L2_VBI_* */ + __u32 reserved[2]; /* must be zero */ +}; + +/* VBI flags */ +#define V4L2_VBI_UNSYNC (1 << 0) +#define V4L2_VBI_INTERLACED (1 << 1) + +/* Sliced VBI + * + * This implements is a proposal V4L2 API to allow SLICED VBI + * required for some hardware encoders. It should change without + * notice in the definitive implementation. + */ + +struct <link linkend="v4l2-sliced-vbi-format">v4l2_sliced_vbi_format</link> { + __u16 service_set; + /* service_lines[0][...] specifies lines 0-23 (1-23 used) of the first field + service_lines[1][...] specifies lines 0-23 (1-23 used) of the second field + (equals frame lines 313-336 for 625 line video + standards, 263-286 for 525 line standards) */ + __u16 service_lines[2][24]; + __u32 io_size; + __u32 reserved[2]; /* must be zero */ +}; + +/* Teletext World System Teletext + (WST), defined on ITU-R BT.653-2 */ +#define V4L2_SLICED_TELETEXT_B (0x0001) +/* Video Program System, defined on ETS 300 231*/ +#define V4L2_SLICED_VPS (0x0400) +/* Closed Caption, defined on EIA-608 */ +#define V4L2_SLICED_CAPTION_525 (0x1000) +/* Wide Screen System, defined on ITU-R BT1119.1 */ +#define V4L2_SLICED_WSS_625 (0x4000) + +#define V4L2_SLICED_VBI_525 (V4L2_SLICED_CAPTION_525) +#define V4L2_SLICED_VBI_625 (V4L2_SLICED_TELETEXT_B | V4L2_SLICED_VPS | V4L2_SLICED_WSS_625) + +struct <link linkend="v4l2-sliced-vbi-cap">v4l2_sliced_vbi_cap</link> { + __u16 service_set; + /* service_lines[0][...] specifies lines 0-23 (1-23 used) of the first field + service_lines[1][...] specifies lines 0-23 (1-23 used) of the second field + (equals frame lines 313-336 for 625 line video + standards, 263-286 for 525 line standards) */ + __u16 service_lines[2][24]; + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + __u32 reserved[3]; /* must be 0 */ +}; + +struct <link linkend="v4l2-sliced-vbi-data">v4l2_sliced_vbi_data</link> { + __u32 id; + __u32 field; /* 0: first field, 1: second field */ + __u32 line; /* 1-23 */ + __u32 reserved; /* must be 0 */ + __u8 data[48]; +}; + +/* + * Sliced VBI data inserted into MPEG Streams + */ + +/* + * V4L2_MPEG_STREAM_VBI_FMT_IVTV: + * + * Structure of payload contained in an MPEG 2 Private Stream 1 PES Packet in an + * MPEG-2 Program Pack that contains V4L2_MPEG_STREAM_VBI_FMT_IVTV Sliced VBI + * data + * + * Note, the MPEG-2 Program Pack and Private Stream 1 PES packet header + * definitions are not included here. See the MPEG-2 specifications for details + * on these headers. + */ + +/* Line type IDs */ +#define V4L2_MPEG_VBI_IVTV_TELETEXT_B (1) +#define V4L2_MPEG_VBI_IVTV_CAPTION_525 (4) +#define V4L2_MPEG_VBI_IVTV_WSS_625 (5) +#define V4L2_MPEG_VBI_IVTV_VPS (7) + +struct <link linkend="v4l2-mpeg-vbi-itv0-line">v4l2_mpeg_vbi_itv0_line</link> { + __u8 id; /* One of V4L2_MPEG_VBI_IVTV_* above */ + __u8 data[42]; /* Sliced VBI data for the line */ +} __attribute__ ((packed)); + +struct <link linkend="v4l2-mpeg-vbi-itv0">v4l2_mpeg_vbi_itv0</link> { + __le32 linemask[2]; /* Bitmasks of VBI service lines present */ + struct <link linkend="v4l2-mpeg-vbi-itv0-line">v4l2_mpeg_vbi_itv0_line</link> line[35]; +} __attribute__ ((packed)); + +struct <link linkend="v4l2-mpeg-vbi-itv0-1">v4l2_mpeg_vbi_ITV0</link> { + struct <link linkend="v4l2-mpeg-vbi-itv0-line">v4l2_mpeg_vbi_itv0_line</link> line[36]; +} __attribute__ ((packed)); + +#define V4L2_MPEG_VBI_IVTV_MAGIC0 "itv0" +#define V4L2_MPEG_VBI_IVTV_MAGIC1 "ITV0" + +struct <link linkend="v4l2-mpeg-vbi-fmt-ivtv">v4l2_mpeg_vbi_fmt_ivtv</link> { + __u8 magic[4]; + union { + struct <link linkend="v4l2-mpeg-vbi-itv0">v4l2_mpeg_vbi_itv0</link> itv0; + struct <link linkend="v4l2-mpeg-vbi-itv0-1">v4l2_mpeg_vbi_ITV0</link> ITV0; + }; +} __attribute__ ((packed)); + +/* + * A G G R E G A T E S T R U C T U R E S + */ + +/* Stream data format + */ +struct <link linkend="v4l2-format">v4l2_format</link> { + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + union { + struct <link linkend="v4l2-pix-format">v4l2_pix_format</link> pix; /* V4L2_BUF_TYPE_VIDEO_CAPTURE */ + struct <link linkend="v4l2-window">v4l2_window</link> win; /* V4L2_BUF_TYPE_VIDEO_OVERLAY */ + struct <link linkend="v4l2-vbi-format">v4l2_vbi_format</link> vbi; /* V4L2_BUF_TYPE_VBI_CAPTURE */ + struct <link linkend="v4l2-sliced-vbi-format">v4l2_sliced_vbi_format</link> sliced; /* V4L2_BUF_TYPE_SLICED_VBI_CAPTURE */ + __u8 raw_data[200]; /* user-defined */ + } fmt; +}; + + +/* Stream type-dependent parameters + */ +struct <link linkend="v4l2-streamparm">v4l2_streamparm</link> { + enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type; + union { + struct <link linkend="v4l2-captureparm">v4l2_captureparm</link> capture; + struct <link linkend="v4l2-outputparm">v4l2_outputparm</link> output; + __u8 raw_data[200]; /* user-defined */ + } parm; +}; + +/* + * A D V A N C E D D E B U G G I N G + * + * NOTE: EXPERIMENTAL API, NEVER RELY ON THIS IN APPLICATIONS! + * FOR DEBUGGING, TESTING AND INTERNAL USE ONLY! + */ + +/* VIDIOC_DBG_G_REGISTER and VIDIOC_DBG_S_REGISTER */ + +#define V4L2_CHIP_MATCH_HOST 0 /* Match against chip ID on host (0 for the host) */ +#define V4L2_CHIP_MATCH_I2C_DRIVER 1 /* Match against I2C driver name */ +#define V4L2_CHIP_MATCH_I2C_ADDR 2 /* Match against I2C 7-bit address */ +#define V4L2_CHIP_MATCH_AC97 3 /* Match against anciliary AC97 chip */ + +struct <link linkend="v4l2-dbg-match">v4l2_dbg_match</link> { + __u32 type; /* Match type */ + union { /* Match this chip, meaning determined by type */ + __u32 addr; + char name[32]; + }; +} __attribute__ ((packed)); + +struct <link linkend="v4l2-dbg-register">v4l2_dbg_register</link> { + struct <link linkend="v4l2-dbg-match">v4l2_dbg_match</link> match; + __u32 size; /* register size in bytes */ + __u64 reg; + __u64 val; +} __attribute__ ((packed)); + +/* VIDIOC_DBG_G_CHIP_IDENT */ +struct <link linkend="v4l2-dbg-chip-ident">v4l2_dbg_chip_ident</link> { + struct <link linkend="v4l2-dbg-match">v4l2_dbg_match</link> match; + __u32 ident; /* chip identifier as specified in <media/v4l2-chip-ident.h> */ + __u32 revision; /* chip revision, chip specific */ +} __attribute__ ((packed)); + +/* + * I O C T L C O D E S F O R V I D E O D E V I C E S + * + */ +#define VIDIOC_QUERYCAP _IOR('V', 0, struct <link linkend="v4l2-capability">v4l2_capability</link>) +#define VIDIOC_RESERVED _IO('V', 1) +#define VIDIOC_ENUM_FMT _IOWR('V', 2, struct <link linkend="v4l2-fmtdesc">v4l2_fmtdesc</link>) +#define VIDIOC_G_FMT _IOWR('V', 4, struct <link linkend="v4l2-format">v4l2_format</link>) +#define VIDIOC_S_FMT _IOWR('V', 5, struct <link linkend="v4l2-format">v4l2_format</link>) +#define VIDIOC_REQBUFS _IOWR('V', 8, struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link>) +#define VIDIOC_QUERYBUF _IOWR('V', 9, struct <link linkend="v4l2-buffer">v4l2_buffer</link>) +#define VIDIOC_G_FBUF _IOR('V', 10, struct <link linkend="v4l2-framebuffer">v4l2_framebuffer</link>) +#define VIDIOC_S_FBUF _IOW('V', 11, struct <link linkend="v4l2-framebuffer">v4l2_framebuffer</link>) +#define VIDIOC_OVERLAY _IOW('V', 14, int) +#define VIDIOC_QBUF _IOWR('V', 15, struct <link linkend="v4l2-buffer">v4l2_buffer</link>) +#define VIDIOC_DQBUF _IOWR('V', 17, struct <link linkend="v4l2-buffer">v4l2_buffer</link>) +#define VIDIOC_STREAMON _IOW('V', 18, int) +#define VIDIOC_STREAMOFF _IOW('V', 19, int) +#define VIDIOC_G_PARM _IOWR('V', 21, struct <link linkend="v4l2-streamparm">v4l2_streamparm</link>) +#define VIDIOC_S_PARM _IOWR('V', 22, struct <link linkend="v4l2-streamparm">v4l2_streamparm</link>) +#define VIDIOC_G_STD _IOR('V', 23, v4l2_std_id) +#define VIDIOC_S_STD _IOW('V', 24, v4l2_std_id) +#define VIDIOC_ENUMSTD _IOWR('V', 25, struct <link linkend="v4l2-standard">v4l2_standard</link>) +#define VIDIOC_ENUMINPUT _IOWR('V', 26, struct <link linkend="v4l2-input">v4l2_input</link>) +#define VIDIOC_G_CTRL _IOWR('V', 27, struct <link linkend="v4l2-control">v4l2_control</link>) +#define VIDIOC_S_CTRL _IOWR('V', 28, struct <link linkend="v4l2-control">v4l2_control</link>) +#define VIDIOC_G_TUNER _IOWR('V', 29, struct <link linkend="v4l2-tuner">v4l2_tuner</link>) +#define VIDIOC_S_TUNER _IOW('V', 30, struct <link linkend="v4l2-tuner">v4l2_tuner</link>) +#define VIDIOC_G_AUDIO _IOR('V', 33, struct <link linkend="v4l2-audio">v4l2_audio</link>) +#define VIDIOC_S_AUDIO _IOW('V', 34, struct <link linkend="v4l2-audio">v4l2_audio</link>) +#define VIDIOC_QUERYCTRL _IOWR('V', 36, struct <link linkend="v4l2-queryctrl">v4l2_queryctrl</link>) +#define VIDIOC_QUERYMENU _IOWR('V', 37, struct <link linkend="v4l2-querymenu">v4l2_querymenu</link>) +#define VIDIOC_G_INPUT _IOR('V', 38, int) +#define VIDIOC_S_INPUT _IOWR('V', 39, int) +#define VIDIOC_G_OUTPUT _IOR('V', 46, int) +#define VIDIOC_S_OUTPUT _IOWR('V', 47, int) +#define VIDIOC_ENUMOUTPUT _IOWR('V', 48, struct <link linkend="v4l2-output">v4l2_output</link>) +#define VIDIOC_G_AUDOUT _IOR('V', 49, struct <link linkend="v4l2-audioout">v4l2_audioout</link>) +#define VIDIOC_S_AUDOUT _IOW('V', 50, struct <link linkend="v4l2-audioout">v4l2_audioout</link>) +#define VIDIOC_G_MODULATOR _IOWR('V', 54, struct <link linkend="v4l2-modulator">v4l2_modulator</link>) +#define VIDIOC_S_MODULATOR _IOW('V', 55, struct <link linkend="v4l2-modulator">v4l2_modulator</link>) +#define VIDIOC_G_FREQUENCY _IOWR('V', 56, struct <link linkend="v4l2-frequency">v4l2_frequency</link>) +#define VIDIOC_S_FREQUENCY _IOW('V', 57, struct <link linkend="v4l2-frequency">v4l2_frequency</link>) +#define VIDIOC_CROPCAP _IOWR('V', 58, struct <link linkend="v4l2-cropcap">v4l2_cropcap</link>) +#define VIDIOC_G_CROP _IOWR('V', 59, struct <link linkend="v4l2-crop">v4l2_crop</link>) +#define VIDIOC_S_CROP _IOW('V', 60, struct <link linkend="v4l2-crop">v4l2_crop</link>) +#define VIDIOC_G_JPEGCOMP _IOR('V', 61, struct <link linkend="v4l2-jpegcompression">v4l2_jpegcompression</link>) +#define VIDIOC_S_JPEGCOMP _IOW('V', 62, struct <link linkend="v4l2-jpegcompression">v4l2_jpegcompression</link>) +#define VIDIOC_QUERYSTD _IOR('V', 63, v4l2_std_id) +#define VIDIOC_TRY_FMT _IOWR('V', 64, struct <link linkend="v4l2-format">v4l2_format</link>) +#define VIDIOC_ENUMAUDIO _IOWR('V', 65, struct <link linkend="v4l2-audio">v4l2_audio</link>) +#define VIDIOC_ENUMAUDOUT _IOWR('V', 66, struct <link linkend="v4l2-audioout">v4l2_audioout</link>) +#define VIDIOC_G_PRIORITY _IOR('V', 67, enum <link linkend="v4l2-priority">v4l2_priority</link>) +#define VIDIOC_S_PRIORITY _IOW('V', 68, enum <link linkend="v4l2-priority">v4l2_priority</link>) +#define VIDIOC_G_SLICED_VBI_CAP _IOWR('V', 69, struct <link linkend="v4l2-sliced-vbi-cap">v4l2_sliced_vbi_cap</link>) +#define VIDIOC_LOG_STATUS _IO('V', 70) +#define VIDIOC_G_EXT_CTRLS _IOWR('V', 71, struct <link linkend="v4l2-ext-controls">v4l2_ext_controls</link>) +#define VIDIOC_S_EXT_CTRLS _IOWR('V', 72, struct <link linkend="v4l2-ext-controls">v4l2_ext_controls</link>) +#define VIDIOC_TRY_EXT_CTRLS _IOWR('V', 73, struct <link linkend="v4l2-ext-controls">v4l2_ext_controls</link>) +#if 1 /*KEEP*/ +#define VIDIOC_ENUM_FRAMESIZES _IOWR('V', 74, struct <link linkend="v4l2-frmsizeenum">v4l2_frmsizeenum</link>) +#define VIDIOC_ENUM_FRAMEINTERVALS _IOWR('V', 75, struct <link linkend="v4l2-frmivalenum">v4l2_frmivalenum</link>) +#define VIDIOC_G_ENC_INDEX _IOR('V', 76, struct <link linkend="v4l2-enc-idx">v4l2_enc_idx</link>) +#define VIDIOC_ENCODER_CMD _IOWR('V', 77, struct <link linkend="v4l2-encoder-cmd">v4l2_encoder_cmd</link>) +#define VIDIOC_TRY_ENCODER_CMD _IOWR('V', 78, struct <link linkend="v4l2-encoder-cmd">v4l2_encoder_cmd</link>) +#endif + +#if 1 /*KEEP*/ +/* Experimental, meant for debugging, testing and internal use. + Only implemented if CONFIG_VIDEO_ADV_DEBUG is defined. + You must be root to use these ioctls. Never use these in applications! */ +#define VIDIOC_DBG_S_REGISTER _IOW('V', 79, struct <link linkend="v4l2-dbg-register">v4l2_dbg_register</link>) +#define VIDIOC_DBG_G_REGISTER _IOWR('V', 80, struct <link linkend="v4l2-dbg-register">v4l2_dbg_register</link>) + +/* Experimental, meant for debugging, testing and internal use. + Never use this ioctl in applications! */ +#define VIDIOC_DBG_G_CHIP_IDENT _IOWR('V', 81, struct <link linkend="v4l2-dbg-chip-ident">v4l2_dbg_chip_ident</link>) +#endif + +#define VIDIOC_S_HW_FREQ_SEEK _IOW('V', 82, struct <link linkend="v4l2-hw-freq-seek">v4l2_hw_freq_seek</link>) +/* Reminder: when adding new ioctls please add support for them to + drivers/media/video/v4l2-compat-ioctl32.c as well! */ + +#ifdef __OLD_VIDIOC_ +/* for compatibility, will go away some day */ +#define VIDIOC_OVERLAY_OLD _IOWR('V', 14, int) +#define VIDIOC_S_PARM_OLD _IOW('V', 22, struct <link linkend="v4l2-streamparm">v4l2_streamparm</link>) +#define VIDIOC_S_CTRL_OLD _IOW('V', 28, struct <link linkend="v4l2-control">v4l2_control</link>) +#define VIDIOC_G_AUDIO_OLD _IOWR('V', 33, struct <link linkend="v4l2-audio">v4l2_audio</link>) +#define VIDIOC_G_AUDOUT_OLD _IOWR('V', 49, struct <link linkend="v4l2-audioout">v4l2_audioout</link>) +#define VIDIOC_CROPCAP_OLD _IOR('V', 58, struct <link linkend="v4l2-cropcap">v4l2_cropcap</link>) +#endif + +#define BASE_VIDIOC_PRIVATE 192 /* 192-255 are private */ + +#endif /* __LINUX_VIDEODEV2_H */ +</programlisting> diff --git a/Documentation/DocBook/v4l/vidioc-cropcap.xml b/Documentation/DocBook/v4l/vidioc-cropcap.xml new file mode 100644 index 0000000..816e90e --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-cropcap.xml @@ -0,0 +1,174 @@ +<refentry id="vidioc-cropcap"> + <refmeta> + <refentrytitle>ioctl VIDIOC_CROPCAP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_CROPCAP</refname> + <refpurpose>Information about the video cropping and scaling abilities</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_cropcap +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_CROPCAP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Applications use this function to query the cropping +limits, the pixel aspect of images and to calculate scale factors. +They set the <structfield>type</structfield> field of a v4l2_cropcap +structure to the respective buffer (stream) type and call the +<constant>VIDIOC_CROPCAP</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure. The results are +constant except when switching the video standard. Remember this +switch can occur implicit when switching the video input or +output.</para> + + <table pgwide="1" frame="none" id="v4l2-cropcap"> + <title>struct <structname>v4l2_cropcap</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the data stream, set by the application. +Only these types are valid here: +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver +defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant> +and higher.</entry> + </row> + <row> + <entry>struct <link linkend="v4l2-rect-crop">v4l2_rect</link></entry> + <entry><structfield>bounds</structfield></entry> + <entry>Defines the window within capturing or output is +possible, this may exclude for example the horizontal and vertical +blanking areas. The cropping rectangle cannot exceed these limits. +Width and height are defined in pixels, the driver writer is free to +choose origin and units of the coordinate system in the analog +domain.</entry> + </row> + <row> + <entry>struct <link linkend="v4l2-rect-crop">v4l2_rect</link></entry> + <entry><structfield>defrect</structfield></entry> + <entry>Default cropping rectangle, it shall cover the +"whole picture". Assuming pixel aspect 1/1 this could be for example a +640 × 480 rectangle for NTSC, a +768 × 576 rectangle for PAL and SECAM centered over +the active picture area. The same co-ordinate system as for + <structfield>bounds</structfield> is used.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>pixelaspect</structfield></entry> + <entry><para>This is the pixel aspect (y / x) when no +scaling is applied, the ratio of the actual sampling +frequency and the frequency required to get square +pixels.</para><para>When cropping coordinates refer to square pixels, +the driver sets <structfield>pixelaspect</structfield> to 1/1. Other +common values are 54/59 for PAL and SECAM, 11/10 for NTSC sampled +according to [<xref linkend="itu601" />].</para></entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- NB this table is duplicated in the overlay chapter. --> + + <table pgwide="1" frame="none" id="v4l2-rect-crop"> + <title>struct <structname>v4l2_rect</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__s32</entry> + <entry><structfield>left</structfield></entry> + <entry>Horizontal offset of the top, left corner of the +rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>top</structfield></entry> + <entry>Vertical offset of the top, left corner of the +rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the rectangle, in pixels.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the rectangle, in pixels. Width +and height cannot be negative, the fields are signed for +hysterical reasons. <!-- video4linux-list@redhat.com +on 22 Oct 2002 subject "Re:[V4L][patches!] Re:v4l2/kernel-2.5" --> +</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-cropcap; <structfield>type</structfield> is +invalid or the ioctl is not supported. This is not permitted for +video capture, output and overlay devices, which must support +<constant>VIDIOC_CROPCAP</constant>.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-dbg-g-chip-ident.xml b/Documentation/DocBook/v4l/vidioc-dbg-g-chip-ident.xml new file mode 100644 index 0000000..4a09e20 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-dbg-g-chip-ident.xml @@ -0,0 +1,275 @@ +<refentry id="vidioc-dbg-g-chip-ident"> + <refmeta> + <refentrytitle>ioctl VIDIOC_DBG_G_CHIP_IDENT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_DBG_G_CHIP_IDENT</refname> + <refpurpose>Identify the chips on a TV card</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_dbg_chip_ident +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_DBG_G_CHIP_IDENT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link +linkend="experimental">experimental</link> interface and may change in +the future.</para> + </note> + + <para>For driver debugging purposes this ioctl allows test +applications to query the driver about the chips present on the TV +card. Regular applications must not use it. When you found a chip +specific bug, please contact the linux-media mailing list (&v4l-ml;) +so it can be fixed.</para> + + <para>To query the driver applications must initialize the +<structfield>match.type</structfield> and +<structfield>match.addr</structfield> or <structfield>match.name</structfield> +fields of a &v4l2-dbg-chip-ident; +and call <constant>VIDIOC_DBG_G_CHIP_IDENT</constant> with a pointer to +this structure. On success the driver stores information about the +selected chip in the <structfield>ident</structfield> and +<structfield>revision</structfield> fields. On failure the structure +remains unchanged.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_HOST</constant>, +<structfield>match.addr</structfield> selects the nth non-&i2c; chip +on the TV card. You can enumerate all chips by starting at zero and +incrementing <structfield>match.addr</structfield> by one until +<constant>VIDIOC_DBG_G_CHIP_IDENT</constant> fails with an &EINVAL;. +The number zero always selects the host chip, ⪚ the chip connected +to the PCI or USB bus.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant>, +<structfield>match.name</structfield> contains the I2C driver name. +For instance +<constant>"saa7127"</constant> will match any chip +supported by the saa7127 driver, regardless of its &i2c; bus address. +When multiple chips supported by the same driver are present, the +ioctl will return <constant>V4L2_IDENT_AMBIGUOUS</constant> in the +<structfield>ident</structfield> field.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_I2C_ADDR</constant>, +<structfield>match.addr</structfield> selects a chip by its 7 bit +&i2c; bus address.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_AC97</constant>, +<structfield>match.addr</structfield> selects the nth AC97 chip +on the TV card. You can enumerate all chips by starting at zero and +incrementing <structfield>match.addr</structfield> by one until +<constant>VIDIOC_DBG_G_CHIP_IDENT</constant> fails with an &EINVAL;.</para> + + <para>On success, the <structfield>ident</structfield> field will +contain a chip ID from the Linux +<filename>media/v4l2-chip-ident.h</filename> header file, and the +<structfield>revision</structfield> field will contain a driver +specific value, or zero if no particular revision is associated with +this chip.</para> + + <para>When the driver could not identify the selected chip, +<structfield>ident</structfield> will contain +<constant>V4L2_IDENT_UNKNOWN</constant>. When no chip matched +the ioctl will succeed but the +<structfield>ident</structfield> field will contain +<constant>V4L2_IDENT_NONE</constant>. If multiple chips matched, +<structfield>ident</structfield> will contain +<constant>V4L2_IDENT_AMBIGUOUS</constant>. In all these cases the +<structfield>revision</structfield> field remains unchanged.</para> + + <para>This ioctl is optional, not all drivers may support it. It +was introduced in Linux 2.6.21, but the API was changed to the +one described here in 2.6.29.</para> + + <para>We recommended the <application>v4l2-dbg</application> +utility over calling this ioctl directly. It is available from the +LinuxTV v4l-dvb repository; see <ulink +url="http://linuxtv.org/repo/">http://linuxtv.org/repo/</ulink> for +access instructions.</para> + + <!-- Note for convenience vidioc-dbg-g-register.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="ident-v4l2-dbg-match"> + <title>struct <structname>v4l2_dbg_match</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>See <xref linkend="ident-chip-match-types" /> for a list of +possible types.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>addr</structfield></entry> + <entry>Match a chip by this number, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + <row> + <entry></entry> + <entry>char</entry> + <entry><structfield>name[32]</structfield></entry> + <entry>Match a chip by this name, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-dbg-chip-ident"> + <title>struct <structname>v4l2_dbg_chip_ident</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>struct v4l2_dbg_match</entry> + <entry><structfield>match</structfield></entry> + <entry>How to match the chip, see <xref linkend="ident-v4l2-dbg-match" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>ident</structfield></entry> + <entry>A chip identifier as defined in the Linux +<filename>media/v4l2-chip-ident.h</filename> header file, or one of +the values from <xref linkend="chip-ids" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>revision</structfield></entry> + <entry>A chip revision, chip and driver specific.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Note for convenience vidioc-dbg-g-register.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="ident-chip-match-types"> + <title>Chip Match Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CHIP_MATCH_HOST</constant></entry> + <entry>0</entry> + <entry>Match the nth chip on the card, zero for the + host chip. Does not match &i2c; chips.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant></entry> + <entry>1</entry> + <entry>Match an &i2c; chip by its driver name.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_ADDR</constant></entry> + <entry>2</entry> + <entry>Match a chip by its 7 bit &i2c; bus address.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry> + <entry>3</entry> + <entry>Match the nth anciliary AC97 chip.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- This is an anonymous enum in media/v4l2-chip-ident.h. --> + <table pgwide="1" frame="none" id="chip-ids"> + <title>Chip Identifiers</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_IDENT_NONE</constant></entry> + <entry>0</entry> + <entry>No chip matched.</entry> + </row> + <row> + <entry><constant>V4L2_IDENT_AMBIGUOUS</constant></entry> + <entry>1</entry> + <entry>Multiple chips matched.</entry> + </row> + <row> + <entry><constant>V4L2_IDENT_UNKNOWN</constant></entry> + <entry>2</entry> + <entry>A chip is present at this address, but the driver +could not identify it.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The driver does not support this ioctl, or the +<structfield>match_type</structfield> is invalid.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-dbg-g-register.xml b/Documentation/DocBook/v4l/vidioc-dbg-g-register.xml new file mode 100644 index 0000000..980c7f3 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-dbg-g-register.xml @@ -0,0 +1,275 @@ +<refentry id="vidioc-dbg-g-register"> + <refmeta> + <refentrytitle>ioctl VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_DBG_G_REGISTER</refname> + <refname>VIDIOC_DBG_S_REGISTER</refname> + <refpurpose>Read or write hardware registers</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_dbg_register *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_dbg_register +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_DBG_G_REGISTER, VIDIOC_DBG_S_REGISTER</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>For driver debugging purposes these ioctls allow test +applications to access hardware registers directly. Regular +applications must not use them.</para> + + <para>Since writing or even reading registers can jeopardize the +system security, its stability and damage the hardware, both ioctls +require superuser privileges. Additionally the Linux kernel must be +compiled with the <constant>CONFIG_VIDEO_ADV_DEBUG</constant> option +to enable these ioctls.</para> + + <para>To write a register applications must initialize all fields +of a &v4l2-dbg-register; and call +<constant>VIDIOC_DBG_S_REGISTER</constant> with a pointer to this +structure. The <structfield>match.type</structfield> and +<structfield>match.addr</structfield> or <structfield>match.name</structfield> +fields select a chip on the TV +card, the <structfield>reg</structfield> field specifies a register +number and the <structfield>val</structfield> field the value to be +written into the register.</para> + + <para>To read a register applications must initialize the +<structfield>match.type</structfield>, +<structfield>match.chip</structfield> or <structfield>match.name</structfield> and +<structfield>reg</structfield> fields, and call +<constant>VIDIOC_DBG_G_REGISTER</constant> with a pointer to this +structure. On success the driver stores the register value in the +<structfield>val</structfield> field. On failure the structure remains +unchanged.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_HOST</constant>, +<structfield>match.addr</structfield> selects the nth non-&i2c; chip +on the TV card. The number zero always selects the host chip, ⪚ the +chip connected to the PCI or USB bus. You can find out which chips are +present with the &VIDIOC-DBG-G-CHIP-IDENT; ioctl.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant>, +<structfield>match.name</structfield> contains the I2C driver name. +For instance +<constant>"saa7127"</constant> will match any chip +supported by the saa7127 driver, regardless of its &i2c; bus address. +When multiple chips supported by the same driver are present, the +effect of these ioctls is undefined. Again with the +&VIDIOC-DBG-G-CHIP-IDENT; ioctl you can find out which &i2c; chips are +present.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_I2C_ADDR</constant>, +<structfield>match.addr</structfield> selects a chip by its 7 bit &i2c; +bus address.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_AC97</constant>, +<structfield>match.addr</structfield> selects the nth AC97 chip +on the TV card.</para> + + <note> + <title>Success not guaranteed</title> + + <para>Due to a flaw in the Linux &i2c; bus driver these ioctls may +return successfully without actually reading or writing a register. To +catch the most likely failure we recommend a &VIDIOC-DBG-G-CHIP-IDENT; +call confirming the presence of the selected &i2c; chip.</para> + </note> + + <para>These ioctls are optional, not all drivers may support them. +However when a driver supports these ioctls it must also support +&VIDIOC-DBG-G-CHIP-IDENT;. Conversely it may support +<constant>VIDIOC_DBG_G_CHIP_IDENT</constant> but not these ioctls.</para> + + <para><constant>VIDIOC_DBG_G_REGISTER</constant> and +<constant>VIDIOC_DBG_S_REGISTER</constant> were introduced in Linux +2.6.21, but their API was changed to the one described here in kernel 2.6.29.</para> + + <para>We recommended the <application>v4l2-dbg</application> +utility over calling these ioctls directly. It is available from the +LinuxTV v4l-dvb repository; see <ulink +url="http://linuxtv.org/repo/">http://linuxtv.org/repo/</ulink> for +access instructions.</para> + + <!-- Note for convenience vidioc-dbg-g-chip-ident.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="v4l2-dbg-match"> + <title>struct <structname>v4l2_dbg_match</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>See <xref linkend="ident-chip-match-types" /> for a list of +possible types.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>addr</structfield></entry> + <entry>Match a chip by this number, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + <row> + <entry></entry> + <entry>char</entry> + <entry><structfield>name[32]</structfield></entry> + <entry>Match a chip by this name, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + </tbody> + </tgroup> + </table> + + + <table pgwide="1" frame="none" id="v4l2-dbg-register"> + <title>struct <structname>v4l2_dbg_register</structname></title> + <tgroup cols="4"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c4" /> + <tbody valign="top"> + <row> + <entry>struct v4l2_dbg_match</entry> + <entry><structfield>match</structfield></entry> + <entry>How to match the chip, see <xref linkend="v4l2-dbg-match" />.</entry> + </row> + <row> + <entry>__u64</entry> + <entry><structfield>reg</structfield></entry> + <entry>A register number.</entry> + </row> + <row> + <entry>__u64</entry> + <entry><structfield>val</structfield></entry> + <entry>The value read from, or to be written into the +register.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Note for convenience vidioc-dbg-g-chip-ident.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="chip-match-types"> + <title>Chip Match Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CHIP_MATCH_HOST</constant></entry> + <entry>0</entry> + <entry>Match the nth chip on the card, zero for the + host chip. Does not match &i2c; chips.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant></entry> + <entry>1</entry> + <entry>Match an &i2c; chip by its driver name.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_ADDR</constant></entry> + <entry>2</entry> + <entry>Match a chip by its 7 bit &i2c; bus address.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry> + <entry>3</entry> + <entry>Match the nth anciliary AC97 chip.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The driver does not support this ioctl, or the kernel +was not compiled with the <constant>CONFIG_VIDEO_ADV_DEBUG</constant> +option, or the <structfield>match_type</structfield> is invalid, or the +selected chip or register does not exist.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EPERM</errorcode></term> + <listitem> + <para>Insufficient permissions. Root privileges are required +to execute these ioctls.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-encoder-cmd.xml b/Documentation/DocBook/v4l/vidioc-encoder-cmd.xml new file mode 100644 index 0000000..b0dde94 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-encoder-cmd.xml @@ -0,0 +1,204 @@ +<refentry id="vidioc-encoder-cmd"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENCODER_CMD</refname> + <refname>VIDIOC_TRY_ENCODER_CMD</refname> + <refpurpose>Execute an encoder command</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_encoder_cmd *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>These ioctls control an audio/video (usually MPEG-) encoder. +<constant>VIDIOC_ENCODER_CMD</constant> sends a command to the +encoder, <constant>VIDIOC_TRY_ENCODER_CMD</constant> can be used to +try a command without actually executing it.</para> + + <para>To send a command applications must initialize all fields of a + &v4l2-encoder-cmd; and call + <constant>VIDIOC_ENCODER_CMD</constant> or + <constant>VIDIOC_TRY_ENCODER_CMD</constant> with a pointer to this + structure.</para> + + <para>The <structfield>cmd</structfield> field must contain the +command code. The <structfield>flags</structfield> field is currently +only used by the STOP command and contains one bit: If the +<constant>V4L2_ENC_CMD_STOP_AT_GOP_END</constant> flag is set, +encoding will continue until the end of the current <wordasword>Group +Of Pictures</wordasword>, otherwise it will stop immediately.</para> + + <para>A <function>read</function>() call sends a START command to +the encoder if it has not been started yet. After a STOP command, +<function>read</function>() calls will read the remaining data +buffered by the driver. When the buffer is empty, +<function>read</function>() will return zero and the next +<function>read</function>() call will restart the encoder.</para> + + <para>A <function>close</function>() call sends an immediate STOP +to the encoder, and all buffered data is discarded.</para> + + <para>These ioctls are optional, not all drivers may support +them. They were introduced in Linux 2.6.21.</para> + + <table pgwide="1" frame="none" id="v4l2-encoder-cmd"> + <title>struct <structname>v4l2_encoder_cmd</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>cmd</structfield></entry> + <entry>The encoder command, see <xref linkend="encoder-cmds" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Flags to go with the command, see <xref + linkend="encoder-flags" />. If no flags are defined for +this command, drivers and applications must set this field to +zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>data</structfield>[8]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="encoder-cmds"> + <title>Encoder Commands</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_ENC_CMD_START</constant></entry> + <entry>0</entry> + <entry>Start the encoder. When the encoder is already +running or paused, this command does nothing. No flags are defined for +this command.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_CMD_STOP</constant></entry> + <entry>1</entry> + <entry>Stop the encoder. When the +<constant>V4L2_ENC_CMD_STOP_AT_GOP_END</constant> flag is set, +encoding will continue until the end of the current <wordasword>Group +Of Pictures</wordasword>, otherwise encoding will stop immediately. +When the encoder is already stopped, this command does +nothing.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_CMD_PAUSE</constant></entry> + <entry>2</entry> + <entry>Pause the encoder. When the encoder has not been +started yet, the driver will return an &EPERM;. When the encoder is +already paused, this command does nothing. No flags are defined for +this command.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_CMD_RESUME</constant></entry> + <entry>3</entry> + <entry>Resume encoding after a PAUSE command. When the +encoder has not been started yet, the driver will return an &EPERM;. +When the encoder is already running, this command does nothing. No +flags are defined for this command.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="encoder-flags"> + <title>Encoder Command Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_ENC_CMD_STOP_AT_GOP_END</constant></entry> + <entry>0x0001</entry> + <entry>Stop encoding at the end of the current <wordasword>Group Of +Pictures</wordasword>, rather than immediately.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The driver does not support this ioctl, or the +<structfield>cmd</structfield> field is invalid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EPERM</errorcode></term> + <listitem> + <para>The application sent a PAUSE or RESUME command when +the encoder was not running.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-enum-fmt.xml b/Documentation/DocBook/v4l/vidioc-enum-fmt.xml new file mode 100644 index 0000000..960d446 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enum-fmt.xml @@ -0,0 +1,164 @@ +<refentry id="vidioc-enum-fmt"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUM_FMT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUM_FMT</refname> + <refpurpose>Enumerate image formats</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_fmtdesc +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUM_FMT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To enumerate image formats applications initialize the +<structfield>type</structfield> and <structfield>index</structfield> +field of &v4l2-fmtdesc; and call the +<constant>VIDIOC_ENUM_FMT</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL;. All formats are enumerable by beginning at index zero and +incrementing by one until <errorcode>EINVAL</errorcode> is +returned.</para> + + <table pgwide="1" frame="none" id="v4l2-fmtdesc"> + <title>struct <structname>v4l2_fmtdesc</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the format in the enumeration, set by +the application. This is in no way related to the <structfield> +pixelformat</structfield> field.</entry> + </row> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the data stream, set by the application. +Only these types are valid here: +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver +defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant> +and higher.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>See <xref linkend="fmtdesc-flags" /></entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>description</structfield>[32]</entry> + <entry>Description of the format, a NUL-terminated ASCII +string. This information is intended for the user, for example: "YUV +4:2:2".</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixelformat</structfield></entry> + <entry>The image format identifier. This is a +four character code as computed by the v4l2_fourcc() +macro:</entry> + </row> + <row> + <entry spanname="hspan"><para><programlisting id="v4l2-fourcc"> +#define v4l2_fourcc(a,b,c,d) (((__u32)(a)<<0)|((__u32)(b)<<8)|((__u32)(c)<<16)|((__u32)(d)<<24)) +</programlisting></para><para>Several image formats are already +defined by this specification in <xref linkend="pixfmt" />. Note these +codes are not the same as those used in the Windows world.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="fmtdesc-flags"> + <title>Image Format Description Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FMT_FLAG_COMPRESSED</constant></entry> + <entry>0x0001</entry> + <entry>This is a compressed format.</entry> + </row> + <row> + <entry><constant>V4L2_FMT_FLAG_EMULATED</constant></entry> + <entry>0x0002</entry> + <entry>This format is not native to the device but emulated +through software (usually libv4l2), where possible try to use a native format +instead for better performance.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-fmtdesc; <structfield>type</structfield> +is not supported or the <structfield>index</structfield> is out of +bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-enum-frameintervals.xml b/Documentation/DocBook/v4l/vidioc-enum-frameintervals.xml new file mode 100644 index 0000000..3c216e1 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enum-frameintervals.xml @@ -0,0 +1,270 @@ +<refentry id="vidioc-enum-frameintervals"> + + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUM_FRAMEINTERVALS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUM_FRAMEINTERVALS</refname> + <refpurpose>Enumerate frame intervals</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_frmivalenum *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUM_FRAMEINTERVALS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a &v4l2-frmivalenum; structure that +contains a pixel format and size and receives a frame interval.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl allows applications to enumerate all frame +intervals that the device supports for the given pixel format and +frame size.</para> + <para>The supported pixel formats and frame sizes can be obtained +by using the &VIDIOC-ENUM-FMT; and &VIDIOC-ENUM-FRAMESIZES; +functions.</para> + <para>The return value and the content of the +<structfield>v4l2_frmivalenum.type</structfield> field depend on the +type of frame intervals the device supports. Here are the semantics of +the function for the different cases:</para> + <itemizedlist> + <listitem> + <para><emphasis role="bold">Discrete:</emphasis> The function +returns success if the given index value (zero-based) is valid. The +application should increase the index by one for each call until +<constant>EINVAL</constant> is returned. The `v4l2_frmivalenum.type` +field is set to `V4L2_FRMIVAL_TYPE_DISCRETE` by the driver. Of the +union only the `discrete` member is valid.</para> + </listitem> + <listitem> + <para><emphasis role="bold">Step-wise:</emphasis> The function +returns success if the given index value is zero and +<constant>EINVAL</constant> for any other index value. The +<structfield>v4l2_frmivalenum.type</structfield> field is set to +<constant>V4L2_FRMIVAL_TYPE_STEPWISE</constant> by the driver. Of the +union only the <structfield>stepwise</structfield> member is +valid.</para> + </listitem> + <listitem> + <para><emphasis role="bold">Continuous:</emphasis> This is a +special case of the step-wise type above. The function returns success +if the given index value is zero and <constant>EINVAL</constant> for +any other index value. The +<structfield>v4l2_frmivalenum.type</structfield> field is set to +<constant>V4L2_FRMIVAL_TYPE_CONTINUOUS</constant> by the driver. Of +the union only the <structfield>stepwise</structfield> member is valid +and the <structfield>step</structfield> value is set to 1.</para> + </listitem> + </itemizedlist> + + <para>When the application calls the function with index zero, it +must check the <structfield>type</structfield> field to determine the +type of frame interval enumeration the device supports. Only for the +<constant>V4L2_FRMIVAL_TYPE_DISCRETE</constant> type does it make +sense to increase the index value to receive more frame +intervals.</para> + <para>Note that the order in which the frame intervals are +returned has no special meaning. In particular does it not say +anything about potential default frame intervals.</para> + <para>Applications can assume that the enumeration data does not +change without any interaction from the application itself. This means +that the enumeration data is consistent if the application does not +perform any other ioctl calls while it runs the frame interval +enumeration.</para> + </refsect1> + + <refsect1> + <title>Notes</title> + + <itemizedlist> + <listitem> + <para><emphasis role="bold">Frame intervals and frame +rates:</emphasis> The V4L2 API uses frame intervals instead of frame +rates. Given the frame interval the frame rate can be computed as +follows:<screen>frame_rate = 1 / frame_interval</screen></para> + </listitem> + </itemizedlist> + + </refsect1> + + <refsect1> + <title>Structs</title> + + <para>In the structs below, <emphasis>IN</emphasis> denotes a +value that has to be filled in by the application, +<emphasis>OUT</emphasis> denotes values that the driver fills in. The +application should zero out all members except for the +<emphasis>IN</emphasis> fields.</para> + + <table pgwide="1" frame="none" id="v4l2-frmival-stepwise"> + <title>struct <structname>v4l2_frmival_stepwise</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>min</structfield></entry> + <entry>Minimum frame interval [s].</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>max</structfield></entry> + <entry>Maximum frame interval [s].</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>step</structfield></entry> + <entry>Frame interval step size [s].</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-frmivalenum"> + <title>struct <structname>v4l2_frmivalenum</structname></title> + <tgroup cols="4"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry></entry> + <entry>IN: Index of the given frame interval in the +enumeration.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixel_format</structfield></entry> + <entry></entry> + <entry>IN: Pixel format for which the frame intervals are +enumerated.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry></entry> + <entry>IN: Frame width for which the frame intervals are +enumerated.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry></entry> + <entry>IN: Frame height for which the frame intervals are +enumerated.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>OUT: Frame interval type the device supports.</entry> + </row> + <row> + <entry>union</entry> + <entry></entry> + <entry></entry> + <entry>OUT: Frame interval with the given index.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-fract;</entry> + <entry><structfield>discrete</structfield></entry> + <entry>Frame interval [s].</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-frmival-stepwise;</entry> + <entry><structfield>stepwise</structfield></entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved[2]</structfield></entry> + <entry></entry> + <entry>Reserved space for future use.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + <title>Enums</title> + + <table pgwide="1" frame="none" id="v4l2-frmivaltypes"> + <title>enum <structname>v4l2_frmivaltypes</structname></title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FRMIVAL_TYPE_DISCRETE</constant></entry> + <entry>1</entry> + <entry>Discrete frame interval.</entry> + </row> + <row> + <entry><constant>V4L2_FRMIVAL_TYPE_CONTINUOUS</constant></entry> + <entry>2</entry> + <entry>Continuous frame interval.</entry> + </row> + <row> + <entry><constant>V4L2_FRMIVAL_TYPE_STEPWISE</constant></entry> + <entry>3</entry> + <entry>Step-wise defined frame interval.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <para>See the description section above for a list of return +values that <varname>errno</varname> can have.</para> + </refsect1> + +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-enum-framesizes.xml b/Documentation/DocBook/v4l/vidioc-enum-framesizes.xml new file mode 100644 index 0000000..6afa454 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enum-framesizes.xml @@ -0,0 +1,282 @@ +<refentry id="vidioc-enum-framesizes"> + + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUM_FRAMESIZES</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUM_FRAMESIZES</refname> + <refpurpose>Enumerate frame sizes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_frmsizeenum *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUM_FRAMESIZES</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a &v4l2-frmsizeenum; that contains an index +and pixel format and receives a frame width and height.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>This ioctl allows applications to enumerate all frame sizes +(&ie; width and height in pixels) that the device supports for the +given pixel format.</para> + <para>The supported pixel formats can be obtained by using the +&VIDIOC-ENUM-FMT; function.</para> + <para>The return value and the content of the +<structfield>v4l2_frmsizeenum.type</structfield> field depend on the +type of frame sizes the device supports. Here are the semantics of the +function for the different cases:</para> + + <itemizedlist> + <listitem> + <para><emphasis role="bold">Discrete:</emphasis> The function +returns success if the given index value (zero-based) is valid. The +application should increase the index by one for each call until +<constant>EINVAL</constant> is returned. The +<structfield>v4l2_frmsizeenum.type</structfield> field is set to +<constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant> by the driver. Of the +union only the <structfield>discrete</structfield> member is +valid.</para> + </listitem> + <listitem> + <para><emphasis role="bold">Step-wise:</emphasis> The function +returns success if the given index value is zero and +<constant>EINVAL</constant> for any other index value. The +<structfield>v4l2_frmsizeenum.type</structfield> field is set to +<constant>V4L2_FRMSIZE_TYPE_STEPWISE</constant> by the driver. Of the +union only the <structfield>stepwise</structfield> member is +valid.</para> + </listitem> + <listitem> + <para><emphasis role="bold">Continuous:</emphasis> This is a +special case of the step-wise type above. The function returns success +if the given index value is zero and <constant>EINVAL</constant> for +any other index value. The +<structfield>v4l2_frmsizeenum.type</structfield> field is set to +<constant>V4L2_FRMSIZE_TYPE_CONTINUOUS</constant> by the driver. Of +the union only the <structfield>stepwise</structfield> member is valid +and the <structfield>step_width</structfield> and +<structfield>step_height</structfield> values are set to 1.</para> + </listitem> + </itemizedlist> + + <para>When the application calls the function with index zero, it +must check the <structfield>type</structfield> field to determine the +type of frame size enumeration the device supports. Only for the +<constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant> type does it make +sense to increase the index value to receive more frame sizes.</para> + <para>Note that the order in which the frame sizes are returned +has no special meaning. In particular does it not say anything about +potential default format sizes.</para> + <para>Applications can assume that the enumeration data does not +change without any interaction from the application itself. This means +that the enumeration data is consistent if the application does not +perform any other ioctl calls while it runs the frame size +enumeration.</para> + </refsect1> + + <refsect1> + <title>Structs</title> + + <para>In the structs below, <emphasis>IN</emphasis> denotes a +value that has to be filled in by the application, +<emphasis>OUT</emphasis> denotes values that the driver fills in. The +application should zero out all members except for the +<emphasis>IN</emphasis> fields.</para> + + <table pgwide="1" frame="none" id="v4l2-frmsize-discrete"> + <title>struct <structname>v4l2_frmsize_discrete</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the frame [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the frame [pixel].</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-frmsize-stepwise"> + <title>struct <structname>v4l2_frmsize_stepwise</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>min_width</structfield></entry> + <entry>Minimum frame width [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>max_width</structfield></entry> + <entry>Maximum frame width [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>step_width</structfield></entry> + <entry>Frame width step size [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>min_height</structfield></entry> + <entry>Minimum frame height [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>max_height</structfield></entry> + <entry>Maximum frame height [pixel].</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>step_height</structfield></entry> + <entry>Frame height step size [pixel].</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-frmsizeenum"> + <title>struct <structname>v4l2_frmsizeenum</structname></title> + <tgroup cols="4"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry></entry> + <entry>IN: Index of the given frame size in the enumeration.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>pixel_format</structfield></entry> + <entry></entry> + <entry>IN: Pixel format for which the frame sizes are enumerated.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>OUT: Frame size type the device supports.</entry> + </row> + <row> + <entry>union</entry> + <entry></entry> + <entry></entry> + <entry>OUT: Frame size with the given index.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-frmsize-discrete;</entry> + <entry><structfield>discrete</structfield></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-frmsize-stepwise;</entry> + <entry><structfield>stepwise</structfield></entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved[2]</structfield></entry> + <entry></entry> + <entry>Reserved space for future use.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + <title>Enums</title> + + <table pgwide="1" frame="none" id="v4l2-frmsizetypes"> + <title>enum <structname>v4l2_frmsizetypes</structname></title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant></entry> + <entry>1</entry> + <entry>Discrete frame size.</entry> + </row> + <row> + <entry><constant>V4L2_FRMSIZE_TYPE_CONTINUOUS</constant></entry> + <entry>2</entry> + <entry>Continuous frame size.</entry> + </row> + <row> + <entry><constant>V4L2_FRMSIZE_TYPE_STEPWISE</constant></entry> + <entry>3</entry> + <entry>Step-wise defined frame size.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <para>See the description section above for a list of return +values that <varname>errno</varname> can have.</para> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-enumaudio.xml b/Documentation/DocBook/v4l/vidioc-enumaudio.xml new file mode 100644 index 0000000..9ae8f2d --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enumaudio.xml @@ -0,0 +1,86 @@ +<refentry id="vidioc-enumaudio"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMAUDIO</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMAUDIO</refname> + <refpurpose>Enumerate audio inputs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_audio *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMAUDIO</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of an audio input applications +initialize the <structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-audio; +and call the <constant>VIDIOC_ENUMAUDIO</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all audio +inputs applications shall begin at index zero, incrementing by one +until the driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>See <xref linkend="vidioc-g-audio" /> for a description of +&v4l2-audio;.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the audio input is out of bounds, or +there are no audio inputs at all and this ioctl is not +supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-enumaudioout.xml b/Documentation/DocBook/v4l/vidioc-enumaudioout.xml new file mode 100644 index 0000000..d3d7c0a --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enumaudioout.xml @@ -0,0 +1,89 @@ +<refentry id="vidioc-enumaudioout"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMAUDOUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMAUDOUT</refname> + <refpurpose>Enumerate audio outputs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_audioout *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMAUDOUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of an audio output applications +initialize the <structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-audioout; and +call the <constant>VIDIOC_G_AUDOUT</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all audio +outputs applications shall begin at index zero, incrementing by one +until the driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>Note connectors on a TV card to loop back the received audio +signal to a sound card are not audio outputs in this sense.</para> + + <para>See <xref linkend="vidioc-g-audioout" /> for a description of +&v4l2-audioout;.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the audio output is out of bounds, or +there are no audio outputs at all and this ioctl is not +supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-enuminput.xml b/Documentation/DocBook/v4l/vidioc-enuminput.xml new file mode 100644 index 0000000..414856b --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enuminput.xml @@ -0,0 +1,287 @@ +<refentry id="vidioc-enuminput"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMINPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMINPUT</refname> + <refpurpose>Enumerate video inputs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_input +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMINPUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a video input applications +initialize the <structfield>index</structfield> field of &v4l2-input; +and call the <constant>VIDIOC_ENUMINPUT</constant> ioctl with a +pointer to this structure. Drivers fill the rest of the structure or +return an &EINVAL; when the index is out of bounds. To enumerate all +inputs applications shall begin at index zero, incrementing by one +until the driver returns <errorcode>EINVAL</errorcode>.</para> + + <table frame="none" pgwide="1" id="v4l2-input"> + <title>struct <structname>v4l2_input</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the input, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the video input, a NUL-terminated ASCII +string, for example: "Vin (Composite 2)". This information is intended +for the user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the input, see <xref + linkend="input-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>audioset</structfield></entry> + <entry><para>Drivers can enumerate up to 32 video and +audio inputs. This field shows which audio inputs were selectable as +audio source if this was the currently selected video input. It is a +bit mask. The LSB corresponds to audio input 0, the MSB to input 31. +Any number of bits can be set, or none.</para><para>When the driver +does not enumerate audio inputs no bits must be set. Applications +shall not interpret this as lack of audio support. Some drivers +automatically select audio sources and do not enumerate them since +there is no choice anyway.</para><para>For details on audio inputs and +how to select the current input see <xref + linkend="audio" />.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>tuner</structfield></entry> + <entry>Capture devices can have zero or more tuners (RF +demodulators). When the <structfield>type</structfield> is set to +<constant>V4L2_INPUT_TYPE_TUNER</constant> this is an RF connector and +this field identifies the tuner. It corresponds to +&v4l2-tuner; field <structfield>index</structfield>. For details on +tuners see <xref linkend="tuner" />.</entry> + </row> + <row> + <entry>&v4l2-std-id;</entry> + <entry><structfield>std</structfield></entry> + <entry>Every video input supports one or more different +video standards. This field is a set of all supported standards. For +details on video standards and how to switch see <xref +linkend="standard" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>status</structfield></entry> + <entry>This field provides status information about the +input. See <xref linkend="input-status" /> for flags. +With the exception of the sensor orientation bits <structfield>status</structfield> is only valid when this is the +current input.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="input-type"> + <title>Input Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_INPUT_TYPE_TUNER</constant></entry> + <entry>1</entry> + <entry>This input uses a tuner (RF demodulator).</entry> + </row> + <row> + <entry><constant>V4L2_INPUT_TYPE_CAMERA</constant></entry> + <entry>2</entry> + <entry>Analog baseband input, for example CVBS / +Composite Video, S-Video, RGB.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Status flags based on proposal by Mark McClelland, +video4linux-list@redhat.com on 18 Oct 2002, subject "Re: [V4L] Re: +v4l2 api". "Why are some of them inverted? So that the driver doesn't +have to lie about the status in cases where it can't tell one way or +the other. Plus, a status of zero would generally mean that everything +is OK." --> + + <table frame="none" pgwide="1" id="input-status"> + <title>Input Status Flags</title> + <tgroup cols="3"> + <colspec colname="c1" /> + <colspec colname="c2" align="center" /> + <colspec colname="c3" /> + <spanspec namest="c1" nameend="c3" spanname="hspan" + align="left" /> + <tbody valign="top"> + <row> + <entry spanname="hspan">General</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_POWER</constant></entry> + <entry>0x00000001</entry> + <entry>Attached device is off.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_SIGNAL</constant></entry> + <entry>0x00000002</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_COLOR</constant></entry> + <entry>0x00000004</entry> + <entry>The hardware supports color decoding, but does not +detect color modulation in the signal.</entry> + </row> + <row> + <entry spanname="hspan">Sensor Orientation</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_HFLIP</constant></entry> + <entry>0x00000010</entry> + <entry>The input is connected to a device that produces a signal +that is flipped horizontally and does not correct this before passing the +signal to userspace.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_VFLIP</constant></entry> + <entry>0x00000020</entry> + <entry>The input is connected to a device that produces a signal +that is flipped vertically and does not correct this before passing the +signal to userspace. Note that a 180 degree rotation is the same as HFLIP | VFLIP</entry> + </row> + <row> + <entry spanname="hspan">Analog Video</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_H_LOCK</constant></entry> + <entry>0x00000100</entry> + <entry>No horizontal sync lock.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_COLOR_KILL</constant></entry> + <entry>0x00000200</entry> + <entry>A color killer circuit automatically disables color +decoding when it detects no color modulation. When this flag is set +the color killer is enabled <emphasis>and</emphasis> has shut off +color decoding.</entry> + </row> + <row> + <entry spanname="hspan">Digital Video</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_SYNC</constant></entry> + <entry>0x00010000</entry> + <entry>No synchronization lock.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_EQU</constant></entry> + <entry>0x00020000</entry> + <entry>No equalizer lock.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_CARRIER</constant></entry> + <entry>0x00040000</entry> + <entry>Carrier recovery failed.</entry> + </row> + <row> + <entry spanname="hspan">VCR and Set-Top Box</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_MACROVISION</constant></entry> + <entry>0x01000000</entry> + <entry>Macrovision is an analog copy prevention system +mangling the video signal to confuse video recorders. When this +flag is set Macrovision has been detected.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_NO_ACCESS</constant></entry> + <entry>0x02000000</entry> + <entry>Conditional access denied.</entry> + </row> + <row> + <entry><constant>V4L2_IN_ST_VTR</constant></entry> + <entry>0x04000000</entry> + <entry>VTR time constant. [?]</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-input; <structfield>index</structfield> is +out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-enumoutput.xml b/Documentation/DocBook/v4l/vidioc-enumoutput.xml new file mode 100644 index 0000000..e8d16dc --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enumoutput.xml @@ -0,0 +1,172 @@ +<refentry id="vidioc-enumoutput"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMOUTPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMOUTPUT</refname> + <refpurpose>Enumerate video outputs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_output *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMOUTPUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a video outputs applications +initialize the <structfield>index</structfield> field of &v4l2-output; +and call the <constant>VIDIOC_ENUMOUTPUT</constant> ioctl with a +pointer to this structure. Drivers fill the rest of the structure or +return an &EINVAL; when the index is out of bounds. To enumerate all +outputs applications shall begin at index zero, incrementing by one +until the driver returns <errorcode>EINVAL</errorcode>.</para> + + <table frame="none" pgwide="1" id="v4l2-output"> + <title>struct <structname>v4l2_output</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the output, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the video output, a NUL-terminated ASCII +string, for example: "Vout". This information is intended for the +user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the output, see <xref + linkend="output-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>audioset</structfield></entry> + <entry><para>Drivers can enumerate up to 32 video and +audio outputs. This field shows which audio outputs were +selectable as the current output if this was the currently selected +video output. It is a bit mask. The LSB corresponds to audio output 0, +the MSB to output 31. Any number of bits can be set, or +none.</para><para>When the driver does not enumerate audio outputs no +bits must be set. Applications shall not interpret this as lack of +audio support. Drivers may automatically select audio outputs without +enumerating them.</para><para>For details on audio outputs and how to +select the current output see <xref linkend="audio" />.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>modulator</structfield></entry> + <entry>Output devices can have zero or more RF modulators. +When the <structfield>type</structfield> is +<constant>V4L2_OUTPUT_TYPE_MODULATOR</constant> this is an RF +connector and this field identifies the modulator. It corresponds to +&v4l2-modulator; field <structfield>index</structfield>. For details +on modulators see <xref linkend="tuner" />.</entry> + </row> + <row> + <entry>&v4l2-std-id;</entry> + <entry><structfield>std</structfield></entry> + <entry>Every video output supports one or more different +video standards. This field is a set of all supported standards. For +details on video standards and how to switch see <xref + linkend="standard" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="output-type"> + <title>Output Type</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_OUTPUT_TYPE_MODULATOR</constant></entry> + <entry>1</entry> + <entry>This output is an analog TV modulator.</entry> + </row> + <row> + <entry><constant>V4L2_OUTPUT_TYPE_ANALOG</constant></entry> + <entry>2</entry> + <entry>Analog baseband output, for example Composite / +CVBS, S-Video, RGB.</entry> + </row> + <row> + <entry><constant>V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY</constant></entry> + <entry>3</entry> + <entry>[?]</entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-output; <structfield>index</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-enumstd.xml b/Documentation/DocBook/v4l/vidioc-enumstd.xml new file mode 100644 index 0000000..95803fe --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-enumstd.xml @@ -0,0 +1,391 @@ +<refentry id="vidioc-enumstd"> + <refmeta> + <refentrytitle>ioctl VIDIOC_ENUMSTD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_ENUMSTD</refname> + <refpurpose>Enumerate supported video standards</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_standard *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_ENUMSTD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a video standard, +especially a custom (driver defined) one, applications initialize the +<structfield>index</structfield> field of &v4l2-standard; and call the +<constant>VIDIOC_ENUMSTD</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all standards +applications shall begin at index zero, incrementing by one until the +driver returns <errorcode>EINVAL</errorcode>. Drivers may enumerate a +different set of standards after switching the video input or +output.<footnote> + <para>The supported standards may overlap and we need an +unambiguous set to find the current standard returned by +<constant>VIDIOC_G_STD</constant>.</para> + </footnote></para> + + <table pgwide="1" frame="none" id="v4l2-standard"> + <title>struct <structname>v4l2_standard</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the video standard, set by the +application.</entry> + </row> + <row> + <entry>&v4l2-std-id;</entry> + <entry><structfield>id</structfield></entry> + <entry>The bits in this field identify the standard as +one of the common standards listed in <xref linkend="v4l2-std-id" />, +or if bits 32 to 63 are set as custom standards. Multiple bits can be +set if the hardware does not distinguish between these standards, +however separate indices do not indicate the opposite. The +<structfield>id</structfield> must be unique. No other enumerated +<structname>v4l2_standard</structname> structure, for this input or +output anyway, can contain the same set of bits.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[24]</entry> + <entry>Name of the standard, a NUL-terminated ASCII +string, for example: "PAL-B/G", "NTSC Japan". This information is +intended for the user.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>frameperiod</structfield></entry> + <entry>The frame period (not field period) is numerator +/ denominator. For example M/NTSC has a frame period of 1001 / +30000 seconds.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>framelines</structfield></entry> + <entry>Total lines per frame including blanking, +e. g. 625 for B/PAL.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-fract"> + <title>struct <structname>v4l2_fract</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>numerator</structfield></entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>denominator</structfield></entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-std-id"> + <title>typedef <structname>v4l2_std_id</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u64</entry> + <entry><structfield>v4l2_std_id</structfield></entry> + <entry>This type is a set, each bit representing another +video standard as listed below and in <xref +linkend="video-standards" />. The 32 most significant bits are reserved +for custom (driver defined) video standards.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para><programlisting> +#define V4L2_STD_PAL_B ((v4l2_std_id)0x00000001) +#define V4L2_STD_PAL_B1 ((v4l2_std_id)0x00000002) +#define V4L2_STD_PAL_G ((v4l2_std_id)0x00000004) +#define V4L2_STD_PAL_H ((v4l2_std_id)0x00000008) +#define V4L2_STD_PAL_I ((v4l2_std_id)0x00000010) +#define V4L2_STD_PAL_D ((v4l2_std_id)0x00000020) +#define V4L2_STD_PAL_D1 ((v4l2_std_id)0x00000040) +#define V4L2_STD_PAL_K ((v4l2_std_id)0x00000080) + +#define V4L2_STD_PAL_M ((v4l2_std_id)0x00000100) +#define V4L2_STD_PAL_N ((v4l2_std_id)0x00000200) +#define V4L2_STD_PAL_Nc ((v4l2_std_id)0x00000400) +#define V4L2_STD_PAL_60 ((v4l2_std_id)0x00000800) +</programlisting></para><para><constant>V4L2_STD_PAL_60</constant> is +a hybrid standard with 525 lines, 60 Hz refresh rate, and PAL color +modulation with a 4.43 MHz color subcarrier. Some PAL video recorders +can play back NTSC tapes in this mode for display on a 50/60 Hz agnostic +PAL TV.</para><para><programlisting> +#define V4L2_STD_NTSC_M ((v4l2_std_id)0x00001000) +#define V4L2_STD_NTSC_M_JP ((v4l2_std_id)0x00002000) +#define V4L2_STD_NTSC_443 ((v4l2_std_id)0x00004000) +</programlisting></para><para><constant>V4L2_STD_NTSC_443</constant> +is a hybrid standard with 525 lines, 60 Hz refresh rate, and NTSC +color modulation with a 4.43 MHz color +subcarrier.</para><para><programlisting> +#define V4L2_STD_NTSC_M_KR ((v4l2_std_id)0x00008000) + +#define V4L2_STD_SECAM_B ((v4l2_std_id)0x00010000) +#define V4L2_STD_SECAM_D ((v4l2_std_id)0x00020000) +#define V4L2_STD_SECAM_G ((v4l2_std_id)0x00040000) +#define V4L2_STD_SECAM_H ((v4l2_std_id)0x00080000) +#define V4L2_STD_SECAM_K ((v4l2_std_id)0x00100000) +#define V4L2_STD_SECAM_K1 ((v4l2_std_id)0x00200000) +#define V4L2_STD_SECAM_L ((v4l2_std_id)0x00400000) +#define V4L2_STD_SECAM_LC ((v4l2_std_id)0x00800000) + +/* ATSC/HDTV */ +#define V4L2_STD_ATSC_8_VSB ((v4l2_std_id)0x01000000) +#define V4L2_STD_ATSC_16_VSB ((v4l2_std_id)0x02000000) +</programlisting></para><para><!-- ATSC proposal by Mark McClelland, +video4linux-list@redhat.com on 17 Oct 2002 +--><constant>V4L2_STD_ATSC_8_VSB</constant> and +<constant>V4L2_STD_ATSC_16_VSB</constant> are U.S. terrestrial digital +TV standards. Presently the V4L2 API does not support digital TV. See +also the Linux DVB API at <ulink +url="http://linuxtv.org">http://linuxtv.org</ulink>.</para> +<para><programlisting> +#define V4L2_STD_PAL_BG (V4L2_STD_PAL_B |\ + V4L2_STD_PAL_B1 |\ + V4L2_STD_PAL_G) +#define V4L2_STD_B (V4L2_STD_PAL_B |\ + V4L2_STD_PAL_B1 |\ + V4L2_STD_SECAM_B) +#define V4L2_STD_GH (V4L2_STD_PAL_G |\ + V4L2_STD_PAL_H |\ + V4L2_STD_SECAM_G |\ + V4L2_STD_SECAM_H) +#define V4L2_STD_PAL_DK (V4L2_STD_PAL_D |\ + V4L2_STD_PAL_D1 |\ + V4L2_STD_PAL_K) +#define V4L2_STD_PAL (V4L2_STD_PAL_BG |\ + V4L2_STD_PAL_DK |\ + V4L2_STD_PAL_H |\ + V4L2_STD_PAL_I) +#define V4L2_STD_NTSC (V4L2_STD_NTSC_M |\ + V4L2_STD_NTSC_M_JP |\ + V4L2_STD_NTSC_M_KR) +#define V4L2_STD_MN (V4L2_STD_PAL_M |\ + V4L2_STD_PAL_N |\ + V4L2_STD_PAL_Nc |\ + V4L2_STD_NTSC) +#define V4L2_STD_SECAM_DK (V4L2_STD_SECAM_D |\ + V4L2_STD_SECAM_K |\ + V4L2_STD_SECAM_K1) +#define V4L2_STD_DK (V4L2_STD_PAL_DK |\ + V4L2_STD_SECAM_DK) + +#define V4L2_STD_SECAM (V4L2_STD_SECAM_B |\ + V4L2_STD_SECAM_G |\ + V4L2_STD_SECAM_H |\ + V4L2_STD_SECAM_DK |\ + V4L2_STD_SECAM_L |\ + V4L2_STD_SECAM_LC) + +#define V4L2_STD_525_60 (V4L2_STD_PAL_M |\ + V4L2_STD_PAL_60 |\ + V4L2_STD_NTSC |\ + V4L2_STD_NTSC_443) +#define V4L2_STD_625_50 (V4L2_STD_PAL |\ + V4L2_STD_PAL_N |\ + V4L2_STD_PAL_Nc |\ + V4L2_STD_SECAM) + +#define V4L2_STD_UNKNOWN 0 +#define V4L2_STD_ALL (V4L2_STD_525_60 |\ + V4L2_STD_625_50) +</programlisting></para> + + <table pgwide="1" id="video-standards" orient="land"> + <title>Video Standards (based on [<xref linkend="itu470" />])</title> + <tgroup cols="12" colsep="1" rowsep="1" align="center"> + <colspec colname="c1" align="left" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <colspec colname="c5" /> + <colspec colnum="7" colname="c7" /> + <colspec colnum="9" colname="c9" /> + <colspec colnum="12" colname="c12" /> + <spanspec namest="c2" nameend="c3" spanname="m" align="center" /> + <spanspec namest="c4" nameend="c12" spanname="x" align="center" /> + <spanspec namest="c5" nameend="c7" spanname="b" align="center" /> + <spanspec namest="c9" nameend="c12" spanname="s" align="center" /> + <thead> + <row> + <entry>Characteristics</entry> + <entry><para>M/NTSC<footnote><para>Japan uses a standard +similar to M/NTSC +(V4L2_STD_NTSC_M_JP).</para></footnote></para></entry> + <entry>M/PAL</entry> + <entry><para>N/PAL<footnote><para> The values in +brackets apply to the combination N/PAL a.k.a. +N<subscript>C</subscript> used in Argentina +(V4L2_STD_PAL_Nc).</para></footnote></para></entry> + <entry align="center">B, B1, G/PAL</entry> + <entry align="center">D, D1, K/PAL</entry> + <entry align="center">H/PAL</entry> + <entry align="center">I/PAL</entry> + <entry align="center">B, G/SECAM</entry> + <entry align="center">D, K/SECAM</entry> + <entry align="center">K1/SECAM</entry> + <entry align="center">L/SECAM</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry>Frame lines</entry> + <entry spanname="m">525</entry> + <entry spanname="x">625</entry> + </row> + <row> + <entry>Frame period (s)</entry> + <entry spanname="m">1001/30000</entry> + <entry spanname="x">1/25</entry> + </row> + <row> + <entry>Chrominance sub-carrier frequency (Hz)</entry> + <entry>3579545 ± 10</entry> + <entry>3579611.49 ± 10</entry> + <entry>4433618.75 ± 5 (3582056.25 +± 5)</entry> + <entry spanname="b">4433618.75 ± 5</entry> + <entry>4433618.75 ± 1</entry> + <entry spanname="s">f<subscript>OR</subscript> = +4406250 ± 2000, f<subscript>OB</subscript> = 4250000 +± 2000</entry> + </row> + <row> + <entry>Nominal radio-frequency channel bandwidth +(MHz)</entry> + <entry>6</entry> + <entry>6</entry> + <entry>6</entry> + <entry>B: 7; B1, G: 8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + <entry>8</entry> + </row> + <row> + <entry>Sound carrier relative to vision carrier +(MHz)</entry> + <entry>+ 4.5</entry> + <entry>+ 4.5</entry> + <entry>+ 4.5</entry> + <entry><para>+ 5.5 ± 0.001 +<footnote><para>In the Federal Republic of Germany, Austria, Italy, +the Netherlands, Slovakia and Switzerland a system of two sound +carriers is used, the frequency of the second carrier being +242.1875 kHz above the frequency of the first sound carrier. For +stereophonic sound transmissions a similar system is used in +Australia.</para></footnote> <footnote><para>New Zealand uses a sound +carrier displaced 5.4996 ± 0.0005 MHz from the vision +carrier.</para></footnote> <footnote><para>In Denmark, Finland, New +Zealand, Sweden and Spain a system of two sound carriers is used. In +Iceland, Norway and Poland the same system is being introduced. The +second carrier is 5.85 MHz above the vision carrier and is DQPSK +modulated with 728 kbit/s sound and data multiplex. (NICAM +system)</para></footnote> <footnote><para>In the United Kingdom, a +system of two sound carriers is used. The second sound carrier is +6.552 MHz above the vision carrier and is DQPSK modulated with a +728 kbit/s sound and data multiplex able to carry two sound +channels. (NICAM system)</para></footnote></para></entry> + <entry>+ 6.5 ± 0.001</entry> + <entry>+ 5.5</entry> + <entry>+ 5.9996 ± 0.0005</entry> + <entry>+ 5.5 ± 0.001</entry> + <entry>+ 6.5 ± 0.001</entry> + <entry>+ 6.5</entry> + <entry><para>+ 6.5 <footnote><para>In France, a +digital carrier 5.85 MHz away from the vision carrier may be used in +addition to the main sound carrier. It is modulated in differentially +encoded QPSK with a 728 kbit/s sound and data multiplexer capable of +carrying two sound channels. (NICAM +system)</para></footnote></para></entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-standard; <structfield>index</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-audio.xml b/Documentation/DocBook/v4l/vidioc-g-audio.xml new file mode 100644 index 0000000..65361a8 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-audio.xml @@ -0,0 +1,188 @@ +<refentry id="vidioc-g-audio"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_AUDIO, VIDIOC_S_AUDIO</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_AUDIO</refname> + <refname>VIDIOC_S_AUDIO</refname> + <refpurpose>Query or select the current audio input and its +attributes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_audio *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_audio *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_AUDIO, VIDIOC_S_AUDIO</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current audio input applications zero out the +<structfield>reserved</structfield> array of a &v4l2-audio; +and call the <constant>VIDIOC_G_AUDIO</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the device has no audio inputs, or none which combine +with the current video input.</para> + + <para>Audio inputs have one writable property, the audio mode. To +select the current audio input <emphasis>and</emphasis> change the +audio mode, applications initialize the +<structfield>index</structfield> and <structfield>mode</structfield> +fields, and the +<structfield>reserved</structfield> array of a +<structname>v4l2_audio</structname> structure and call the +<constant>VIDIOC_S_AUDIO</constant> ioctl. Drivers may switch to a +different audio mode if the request cannot be satisfied. However, this +is a write-only ioctl, it does not return the actual new audio +mode.</para> + + <table pgwide="1" frame="none" id="v4l2-audio"> + <title>struct <structname>v4l2_audio</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the audio input, set by the +driver or application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the audio input, a NUL-terminated ASCII +string, for example: "Line In". This information is intended for the +user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>Audio capability flags, see <xref + linkend="audio-capability" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>mode</structfield></entry> + <entry>Audio mode flags set by drivers and applications (on + <constant>VIDIOC_S_AUDIO</constant> ioctl), see <xref linkend="audio-mode" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="audio-capability"> + <title>Audio Capability Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_AUDCAP_STEREO</constant></entry> + <entry>0x00001</entry> + <entry>This is a stereo input. The flag is intended to +automatically disable stereo recording etc. when the signal is always +monaural. The API provides no means to detect if stereo is +<emphasis>received</emphasis>, unless the audio input belongs to a +tuner.</entry> + </row> + <row> + <entry><constant>V4L2_AUDCAP_AVL</constant></entry> + <entry>0x00002</entry> + <entry>Automatic Volume Level mode is supported.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="audio-mode"> + <title>Audio Mode Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_AUDMODE_AVL</constant></entry> + <entry>0x00001</entry> + <entry>AVL mode is on.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>No audio inputs combine with the current video input, +or the number of the selected audio input is out of bounds or it does +not combine, or there are no audio inputs at all and the ioctl is not +supported.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>I/O is in progress, the input cannot be +switched.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-audioout.xml b/Documentation/DocBook/v4l/vidioc-g-audioout.xml new file mode 100644 index 0000000..3632730 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-audioout.xml @@ -0,0 +1,154 @@ +<refentry id="vidioc-g-audioout"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_AUDOUT</refname> + <refname>VIDIOC_S_AUDOUT</refname> + <refpurpose>Query or select the current audio output</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_audioout *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_audioout *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current audio output applications zero out the +<structfield>reserved</structfield> array of a &v4l2-audioout; and +call the <constant>VIDIOC_G_AUDOUT</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the device has no audio inputs, or none which combine +with the current video output.</para> + + <para>Audio outputs have no writable properties. Nevertheless, to +select the current audio output applications can initialize the +<structfield>index</structfield> field and +<structfield>reserved</structfield> array (which in the future may +contain writable properties) of a +<structname>v4l2_audioout</structname> structure and call the +<constant>VIDIOC_S_AUDOUT</constant> ioctl. Drivers switch to the +requested output or return the &EINVAL; when the index is out of +bounds. This is a write-only ioctl, it does not return the current +audio output attributes as <constant>VIDIOC_G_AUDOUT</constant> +does.</para> + + <para>Note connectors on a TV card to loop back the received audio +signal to a sound card are not audio outputs in this sense.</para> + + <table pgwide="1" frame="none" id="v4l2-audioout"> + <title>struct <structname>v4l2_audioout</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the audio output, set by the +driver or application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the audio output, a NUL-terminated ASCII +string, for example: "Line Out". This information is intended for the +user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>Audio capability flags, none defined yet. Drivers +must set this field to zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>mode</structfield></entry> + <entry>Audio mode, none defined yet. Drivers and +applications (on <constant>VIDIOC_S_AUDOUT</constant>) must set this +field to zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>No audio outputs combine with the current video +output, or the number of the selected audio output is out of bounds or +it does not combine, or there are no audio outputs at all and the +ioctl is not supported.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>I/O is in progress, the output cannot be +switched.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-crop.xml b/Documentation/DocBook/v4l/vidioc-g-crop.xml new file mode 100644 index 0000000..d235b1d --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-crop.xml @@ -0,0 +1,143 @@ +<refentry id="vidioc-g-crop"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_CROP, VIDIOC_S_CROP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_CROP</refname> + <refname>VIDIOC_S_CROP</refname> + <refpurpose>Get or set the current cropping rectangle</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_crop *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_crop *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_CROP, VIDIOC_S_CROP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the cropping rectangle size and position +applications set the <structfield>type</structfield> field of a +<structname>v4l2_crop</structname> structure to the respective buffer +(stream) type and call the <constant>VIDIOC_G_CROP</constant> ioctl +with a pointer to this structure. The driver fills the rest of the +structure or returns the &EINVAL; if cropping is not supported.</para> + + <para>To change the cropping rectangle applications initialize the +<structfield>type</structfield> and &v4l2-rect; substructure named +<structfield>c</structfield> of a v4l2_crop structure and call the +<constant>VIDIOC_S_CROP</constant> ioctl with a pointer to this +structure.</para> + + <para>The driver first adjusts the requested dimensions against +hardware limits, &ie; the bounds given by the capture/output window, +and it rounds to the closest possible values of horizontal and +vertical offset, width and height. In particular the driver must round +the vertical offset of the cropping rectangle to frame lines modulo +two, such that the field order cannot be confused.</para> + + <para>Second the driver adjusts the image size (the opposite +rectangle of the scaling process, source or target depending on the +data direction) to the closest size possible while maintaining the +current horizontal and vertical scaling factor.</para> + + <para>Finally the driver programs the hardware with the actual +cropping and image parameters. <constant>VIDIOC_S_CROP</constant> is a +write-only ioctl, it does not return the actual parameters. To query +them applications must call <constant>VIDIOC_G_CROP</constant> and +&VIDIOC-G-FMT;. When the parameters are unsuitable the application may +modify the cropping or image parameters and repeat the cycle until +satisfactory parameters have been negotiated.</para> + + <para>When cropping is not supported then no parameters are +changed and <constant>VIDIOC_S_CROP</constant> returns the +&EINVAL;.</para> + + <table pgwide="1" frame="none" id="v4l2-crop"> + <title>struct <structname>v4l2_crop</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the data stream, set by the application. +Only these types are valid here: <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>, +<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver +defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant> +and higher.</entry> + </row> + <row> + <entry>&v4l2-rect;</entry> + <entry><structfield>c</structfield></entry> + <entry>Cropping rectangle. The same co-ordinate system as +for &v4l2-cropcap; <structfield>bounds</structfield> is used.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>Cropping is not supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-ctrl.xml b/Documentation/DocBook/v4l/vidioc-g-ctrl.xml new file mode 100644 index 0000000..8b5e6ff --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-ctrl.xml @@ -0,0 +1,130 @@ +<refentry id="vidioc-g-ctrl"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_CTRL, VIDIOC_S_CTRL</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_CTRL</refname> + <refname>VIDIOC_S_CTRL</refname> + <refpurpose>Get or set the value of a control</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_control +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_CTRL, VIDIOC_S_CTRL</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To get the current value of a control applications +initialize the <structfield>id</structfield> field of a struct +<structname>v4l2_control</structname> and call the +<constant>VIDIOC_G_CTRL</constant> ioctl with a pointer to this +structure. To change the value of a control applications initialize +the <structfield>id</structfield> and <structfield>value</structfield> +fields of a struct <structname>v4l2_control</structname> and call the +<constant>VIDIOC_S_CTRL</constant> ioctl.</para> + + <para>When the <structfield>id</structfield> is invalid drivers +return an &EINVAL;. When the <structfield>value</structfield> is out +of bounds drivers can choose to take the closest valid value or return +an &ERANGE;, whatever seems more appropriate. However, +<constant>VIDIOC_S_CTRL</constant> is a write-only ioctl, it does not +return the actual new value.</para> + + <para>These ioctls work only with user controls. For other +control classes the &VIDIOC-G-EXT-CTRLS;, &VIDIOC-S-EXT-CTRLS; or +&VIDIOC-TRY-EXT-CTRLS; must be used.</para> + + <table pgwide="1" frame="none" id="v4l2-control"> + <title>struct <structname>v4l2_control</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>Identifies the control, set by the +application.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>value</structfield></entry> + <entry>New value or current value.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-control; <structfield>id</structfield> is +invalid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ERANGE</errorcode></term> + <listitem> + <para>The &v4l2-control; <structfield>value</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The control is temporarily not changeable, possibly +because another applications took over control of the device function +this control belongs to.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-enc-index.xml b/Documentation/DocBook/v4l/vidioc-g-enc-index.xml new file mode 100644 index 0000000..9f242e4 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-enc-index.xml @@ -0,0 +1,213 @@ +<refentry id="vidioc-g-enc-index"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_ENC_INDEX</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_ENC_INDEX</refname> + <refpurpose>Get meta data about a compressed video stream</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_enc_idx *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_ENC_INDEX</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link linkend="experimental">experimental</link> +interface and may change in the future.</para> + </note> + + <para>The <constant>VIDIOC_G_ENC_INDEX</constant> ioctl provides +meta data about a compressed video stream the same or another +application currently reads from the driver, which is useful for +random access into the stream without decoding it.</para> + + <para>To read the data applications must call +<constant>VIDIOC_G_ENC_INDEX</constant> with a pointer to a +&v4l2-enc-idx;. On success the driver fills the +<structfield>entry</structfield> array, stores the number of elements +written in the <structfield>entries</structfield> field, and +initializes the <structfield>entries_cap</structfield> field.</para> + + <para>Each element of the <structfield>entry</structfield> array +contains meta data about one picture. A +<constant>VIDIOC_G_ENC_INDEX</constant> call reads up to +<constant>V4L2_ENC_IDX_ENTRIES</constant> entries from a driver +buffer, which can hold up to <structfield>entries_cap</structfield> +entries. This number can be lower or higher than +<constant>V4L2_ENC_IDX_ENTRIES</constant>, but not zero. When the +application fails to read the meta data in time the oldest entries +will be lost. When the buffer is empty or no capturing/encoding is in +progress, <structfield>entries</structfield> will be zero.</para> + + <para>Currently this ioctl is only defined for MPEG-2 program +streams and video elementary streams.</para> + + <table pgwide="1" frame="none" id="v4l2-enc-idx"> + <title>struct <structname>v4l2_enc_idx</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>entries</structfield></entry> + <entry>The number of entries the driver stored in the +<structfield>entry</structfield> array.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>entries_cap</structfield></entry> + <entry>The number of entries the driver can +buffer. Must be greater than zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry spanname="hspan">Reserved for future extensions. +Drivers must set the array to zero.</entry> + </row> + <row> + <entry>&v4l2-enc-idx-entry;</entry> + <entry><structfield>entry</structfield>[<constant>V4L2_ENC_IDX_ENTRIES</constant>]</entry> + <entry>Meta data about a compressed video stream. Each +element of the array corresponds to one picture, sorted in ascending +order by their <structfield>offset</structfield>.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-enc-idx-entry"> + <title>struct <structname>v4l2_enc_idx_entry</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u64</entry> + <entry><structfield>offset</structfield></entry> + <entry>The offset in bytes from the beginning of the +compressed video stream to the beginning of this picture, that is a +<wordasword>PES packet header</wordasword> as defined in <xref + linkend="mpeg2part1" /> or a <wordasword>picture +header</wordasword> as defined in <xref linkend="mpeg2part2" />. When +the encoder is stopped, the driver resets the offset to zero.</entry> + </row> + <row> + <entry>__u64</entry> + <entry><structfield>pts</structfield></entry> + <entry>The 33 bit <wordasword>Presentation Time +Stamp</wordasword> of this picture as defined in <xref + linkend="mpeg2part1" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>length</structfield></entry> + <entry>The length of this picture in bytes.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Flags containing the coding type of this picture, see <xref + linkend="enc-idx-flags" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. +Drivers must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="enc-idx-flags"> + <title>Index Entry Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_ENC_IDX_FRAME_I</constant></entry> + <entry>0x00</entry> + <entry>This is an Intra-coded picture.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_IDX_FRAME_P</constant></entry> + <entry>0x01</entry> + <entry>This is a Predictive-coded picture.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_IDX_FRAME_B</constant></entry> + <entry>0x02</entry> + <entry>This is a Bidirectionally predictive-coded +picture.</entry> + </row> + <row> + <entry><constant>V4L2_ENC_IDX_FRAME_MASK</constant></entry> + <entry>0x0F</entry> + <entry><wordasword>AND</wordasword> the flags field with +this mask to obtain the picture coding type.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The driver does not support this ioctl.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/v4l/vidioc-g-ext-ctrls.xml new file mode 100644 index 0000000..3aa7f8f --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-ext-ctrls.xml @@ -0,0 +1,307 @@ +<refentry id="vidioc-g-ext-ctrls"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_EXT_CTRLS, VIDIOC_S_EXT_CTRLS, +VIDIOC_TRY_EXT_CTRLS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_EXT_CTRLS</refname> + <refname>VIDIOC_S_EXT_CTRLS</refname> + <refname>VIDIOC_TRY_EXT_CTRLS</refname> + <refpurpose>Get or set the value of several controls, try control +values</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_ext_controls +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_EXT_CTRLS, VIDIOC_S_EXT_CTRLS, +VIDIOC_TRY_EXT_CTRLS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>These ioctls allow the caller to get or set multiple +controls atomically. Control IDs are grouped into control classes (see +<xref linkend="ctrl-class" />) and all controls in the control array +must belong to the same control class.</para> + + <para>Applications must always fill in the +<structfield>count</structfield>, +<structfield>ctrl_class</structfield>, +<structfield>controls</structfield> and +<structfield>reserved</structfield> fields of &v4l2-ext-controls;, and +initialize the &v4l2-ext-control; array pointed to by the +<structfield>controls</structfield> fields.</para> + + <para>To get the current value of a set of controls applications +initialize the <structfield>id</structfield>, +<structfield>size</structfield> and <structfield>reserved2</structfield> fields +of each &v4l2-ext-control; and call the +<constant>VIDIOC_G_EXT_CTRLS</constant> ioctl. String controls controls +must also set the <structfield>string</structfield> field.</para> + + <para>If the <structfield>size</structfield> is too small to +receive the control result (only relevant for pointer-type controls +like strings), then the driver will set <structfield>size</structfield> +to a valid value and return an &ENOSPC;. You should re-allocate the +string memory to this new size and try again. It is possible that the +same issue occurs again if the string has grown in the meantime. It is +recommended to call &VIDIOC-QUERYCTRL; first and use +<structfield>maximum</structfield>+1 as the new <structfield>size</structfield> +value. It is guaranteed that that is sufficient memory. +</para> + + <para>To change the value of a set of controls applications +initialize the <structfield>id</structfield>, <structfield>size</structfield>, +<structfield>reserved2</structfield> and +<structfield>value/string</structfield> fields of each &v4l2-ext-control; and +call the <constant>VIDIOC_S_EXT_CTRLS</constant> ioctl. The controls +will only be set if <emphasis>all</emphasis> control values are +valid.</para> + + <para>To check if a set of controls have correct values applications +initialize the <structfield>id</structfield>, <structfield>size</structfield>, +<structfield>reserved2</structfield> and +<structfield>value/string</structfield> fields of each &v4l2-ext-control; and +call the <constant>VIDIOC_TRY_EXT_CTRLS</constant> ioctl. It is up to +the driver whether wrong values are automatically adjusted to a valid +value or if an error is returned.</para> + + <para>When the <structfield>id</structfield> or +<structfield>ctrl_class</structfield> is invalid drivers return an +&EINVAL;. When the value is out of bounds drivers can choose to take +the closest valid value or return an &ERANGE;, whatever seems more +appropriate. In the first case the new value is set in +&v4l2-ext-control;.</para> + + <para>The driver will only set/get these controls if all control +values are correct. This prevents the situation where only some of the +controls were set/get. Only low-level errors (⪚ a failed i2c +command) can still cause this situation.</para> + + <table pgwide="1" frame="none" id="v4l2-ext-control"> + <title>struct <structname>v4l2_ext_control</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry></entry> + <entry>Identifies the control, set by the +application.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>size</structfield></entry> + <entry></entry> + <entry>The total size in bytes of the payload of this +control. This is normally 0, but for pointer controls this should be +set to the size of the memory containing the payload, or that will +receive the payload. If <constant>VIDIOC_G_EXT_CTRLS</constant> finds +that this value is less than is required to store +the payload result, then it is set to a value large enough to store the +payload result and ENOSPC is returned. Note that for string controls +this <structfield>size</structfield> field should not be confused with the length of the string. +This field refers to the size of the memory that contains the string. +The actual <emphasis>length</emphasis> of the string may well be much smaller. +</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved2</structfield>[1]</entry> + <entry></entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>__s32</entry> + <entry><structfield>value</structfield></entry> + <entry>New value or current value.</entry> + </row> + <row> + <entry></entry> + <entry>__s64</entry> + <entry><structfield>value64</structfield></entry> + <entry>New value or current value.</entry> + </row> + <row> + <entry></entry> + <entry>char *</entry> + <entry><structfield>string</structfield></entry> + <entry>A pointer to a string.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-ext-controls"> + <title>struct <structname>v4l2_ext_controls</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>ctrl_class</structfield></entry> + <entry>The control class to which all controls belong, see +<xref linkend="ctrl-class" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>count</structfield></entry> + <entry>The number of controls in the controls array. May +also be zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>error_idx</structfield></entry> + <entry>Set by the driver in case of an error. It is the +index of the control causing the error or equal to 'count' when the +error is not associated with a particular control. Undefined when the +ioctl returns 0 (success).</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + <row> + <entry>&v4l2-ext-control; *</entry> + <entry><structfield>controls</structfield></entry> + <entry>Pointer to an array of +<structfield>count</structfield> v4l2_ext_control structures. Ignored +if <structfield>count</structfield> equals zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="ctrl-class"> + <title>Control classes</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CTRL_CLASS_USER</constant></entry> + <entry>0x980000</entry> + <entry>The class containing user controls. These controls +are described in <xref linkend="control" />. All controls that can be set +using the &VIDIOC-S-CTRL; and &VIDIOC-G-CTRL; ioctl belong to this +class.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_CLASS_MPEG</constant></entry> + <entry>0x990000</entry> + <entry>The class containing MPEG compression controls. +These controls are described in <xref + linkend="mpeg-controls" />.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_CLASS_CAMERA</constant></entry> + <entry>0x9a0000</entry> + <entry>The class containing camera controls. +These controls are described in <xref + linkend="camera-controls" />.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_CLASS_FM_TX</constant></entry> + <entry>0x9b0000</entry> + <entry>The class containing FM Transmitter (FM TX) controls. +These controls are described in <xref + linkend="fm-tx-controls" />.</entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-ext-control; <structfield>id</structfield> +is invalid or the &v4l2-ext-controls; +<structfield>ctrl_class</structfield> is invalid. This error code is +also returned by the <constant>VIDIOC_S_EXT_CTRLS</constant> and +<constant>VIDIOC_TRY_EXT_CTRLS</constant> ioctls if two or more +control values are in conflict.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ERANGE</errorcode></term> + <listitem> + <para>The &v4l2-ext-control; <structfield>value</structfield> +is out of bounds.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The control is temporarily not changeable, possibly +because another applications took over control of the device function +this control belongs to.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOSPC</errorcode></term> + <listitem> + <para>The space reserved for the control's payload is insufficient. +The field <structfield>size</structfield> is set to a value that is enough +to store the payload and this error code is returned.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-fbuf.xml b/Documentation/DocBook/v4l/vidioc-g-fbuf.xml new file mode 100644 index 0000000..f701706 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-fbuf.xml @@ -0,0 +1,456 @@ +<refentry id="vidioc-g-fbuf"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_FBUF, VIDIOC_S_FBUF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_FBUF</refname> + <refname>VIDIOC_S_FBUF</refname> + <refpurpose>Get or set frame buffer overlay parameters</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_framebuffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_framebuffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_FBUF, VIDIOC_S_FBUF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Applications can use the <constant>VIDIOC_G_FBUF</constant> and +<constant>VIDIOC_S_FBUF</constant> ioctl to get and set the +framebuffer parameters for a <link linkend="overlay">Video +Overlay</link> or <link linkend="osd">Video Output Overlay</link> +(OSD). The type of overlay is implied by the device type (capture or +output device) and can be determined with the &VIDIOC-QUERYCAP; ioctl. +One <filename>/dev/videoN</filename> device must not support both +kinds of overlay.</para> + + <para>The V4L2 API distinguishes destructive and non-destructive +overlays. A destructive overlay copies captured video images into the +video memory of a graphics card. A non-destructive overlay blends +video images into a VGA signal or graphics into a video signal. +<wordasword>Video Output Overlays</wordasword> are always +non-destructive.</para> + + <para>To get the current parameters applications call the +<constant>VIDIOC_G_FBUF</constant> ioctl with a pointer to a +<structname>v4l2_framebuffer</structname> structure. The driver fills +all fields of the structure or returns an &EINVAL; when overlays are +not supported.</para> + + <para>To set the parameters for a <wordasword>Video Output +Overlay</wordasword>, applications must initialize the +<structfield>flags</structfield> field of a struct +<structname>v4l2_framebuffer</structname>. Since the framebuffer is +implemented on the TV card all other parameters are determined by the +driver. When an application calls <constant>VIDIOC_S_FBUF</constant> +with a pointer to this structure, the driver prepares for the overlay +and returns the framebuffer parameters as +<constant>VIDIOC_G_FBUF</constant> does, or it returns an error +code.</para> + + <para>To set the parameters for a <wordasword>non-destructive +Video Overlay</wordasword>, applications must initialize the +<structfield>flags</structfield> field, the +<structfield>fmt</structfield> substructure, and call +<constant>VIDIOC_S_FBUF</constant>. Again the driver prepares for the +overlay and returns the framebuffer parameters as +<constant>VIDIOC_G_FBUF</constant> does, or it returns an error +code.</para> + + <para>For a <wordasword>destructive Video Overlay</wordasword> +applications must additionally provide a +<structfield>base</structfield> address. Setting up a DMA to a +random memory location can jeopardize the system security, its +stability or even damage the hardware, therefore only the superuser +can set the parameters for a destructive video overlay.</para> + + <!-- NB v4l2_pix_format is also specified in pixfmt.sgml.--> + + <table pgwide="1" frame="none" id="v4l2-framebuffer"> + <title>struct <structname>v4l2_framebuffer</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry></entry> + <entry>Overlay capability flags set by the driver, see +<xref linkend="framebuffer-cap" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry></entry> + <entry>Overlay control flags set by application and +driver, see <xref linkend="framebuffer-flags" /></entry> + </row> + <row> + <entry>void *</entry> + <entry><structfield>base</structfield></entry> + <entry></entry> + <entry>Physical base address of the framebuffer, +that is the address of the pixel in the top left corner of the +framebuffer.<footnote><para>A physical base address may not suit all +platforms. GK notes in theory we should pass something like PCI device ++ memory region + offset instead. If you encounter problems please +discuss on the linux-media mailing list: &v4l-ml;.</para></footnote></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>This field is irrelevant to +<wordasword>non-destructive Video Overlays</wordasword>. For +<wordasword>destructive Video Overlays</wordasword> applications must +provide a base address. The driver may accept only base addresses +which are a multiple of two, four or eight bytes. For +<wordasword>Video Output Overlays</wordasword> the driver must return +a valid base address, so applications can find the corresponding Linux +framebuffer device (see <xref linkend="osd" />).</entry> + </row> + <row> + <entry>&v4l2-pix-format;</entry> + <entry><structfield>fmt</structfield></entry> + <entry></entry> + <entry>Layout of the frame buffer. The +<structname>v4l2_pix_format</structname> structure is defined in <xref +linkend="pixfmt" />, for clarification the fields and acceptable values + are listed below:</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>width</structfield></entry> + <entry>Width of the frame buffer in pixels.</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>height</structfield></entry> + <entry>Height of the frame buffer in pixels.</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>pixelformat</structfield></entry> + <entry>The pixel format of the +framebuffer.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>For <wordasword>non-destructive Video +Overlays</wordasword> this field only defines a format for the +&v4l2-window; <structfield>chromakey</structfield> field.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>For <wordasword>destructive Video +Overlays</wordasword> applications must initialize this field. For +<wordasword>Video Output Overlays</wordasword> the driver must return +a valid format.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>Usually this is an RGB format (for example +<link linkend="V4L2-PIX-FMT-RGB565"><constant>V4L2_PIX_FMT_RGB565</constant></link>) +but YUV formats (only packed YUV formats when chroma keying is used, +not including <constant>V4L2_PIX_FMT_YUYV</constant> and +<constant>V4L2_PIX_FMT_UYVY</constant>) and the +<constant>V4L2_PIX_FMT_PAL8</constant> format are also permitted. The +behavior of the driver when an application requests a compressed +format is undefined. See <xref linkend="pixfmt" /> for information on +pixel formats.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-field;</entry> + <entry><structfield>field</structfield></entry> + <entry>Drivers and applications shall ignore this field. +If applicable, the field order is selected with the &VIDIOC-S-FMT; +ioctl, using the <structfield>field</structfield> field of +&v4l2-window;.</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>bytesperline</structfield></entry> + <entry>Distance in bytes between the leftmost pixels in +two adjacent lines.</entry> + </row> + <row> + <entry spanname="hspan"><para>This field is irrelevant to +<wordasword>non-destructive Video +Overlays</wordasword>.</para><para>For <wordasword>destructive Video +Overlays</wordasword> both applications and drivers can set this field +to request padding bytes at the end of each line. Drivers however may +ignore the requested value, returning <structfield>width</structfield> +times bytes-per-pixel or a larger value required by the hardware. That +implies applications can just set this field to zero to get a +reasonable default.</para><para>For <wordasword>Video Output +Overlays</wordasword> the driver must return a valid +value.</para><para>Video hardware may access padding bytes, therefore +they must reside in accessible memory. Consider for example the case +where padding bytes after the last line of an image cross a system +page boundary. Capture devices may write padding bytes, the value is +undefined. Output devices ignore the contents of padding +bytes.</para><para>When the image format is planar the +<structfield>bytesperline</structfield> value applies to the largest +plane and is divided by the same factor as the +<structfield>width</structfield> field for any smaller planes. For +example the Cb and Cr planes of a YUV 4:2:0 image have half as many +padding bytes following each line as the Y plane. To avoid ambiguities +drivers must return a <structfield>bytesperline</structfield> value +rounded up to a multiple of the scale factor.</para></entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>sizeimage</structfield></entry> + <entry><para>This field is irrelevant to +<wordasword>non-destructive Video Overlays</wordasword>. For +<wordasword>destructive Video Overlays</wordasword> applications must +initialize this field. For <wordasword>Video Output +Overlays</wordasword> the driver must return a valid +format.</para><para>Together with <structfield>base</structfield> it +defines the framebuffer memory accessible by the +driver.</para></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-colorspace;</entry> + <entry><structfield>colorspace</structfield></entry> + <entry>This information supplements the +<structfield>pixelformat</structfield> and must be set by the driver, +see <xref linkend="colorspaces" />.</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>priv</structfield></entry> + <entry>Reserved for additional information about custom +(driver defined) formats. When not used drivers and applications must +set this field to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="framebuffer-cap"> + <title>Frame Buffer Capability Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FBUF_CAP_EXTERNOVERLAY</constant></entry> + <entry>0x0001</entry> + <entry>The device is capable of non-destructive overlays. +When the driver clears this flag, only destructive overlays are +supported. There are no drivers yet which support both destructive and +non-destructive overlays.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_CHROMAKEY</constant></entry> + <entry>0x0002</entry> + <entry>The device supports clipping by chroma-keying the +images. That is, image pixels replace pixels in the VGA or video +signal only where the latter assume a certain color. Chroma-keying +makes no sense for destructive overlays.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant></entry> + <entry>0x0004</entry> + <entry>The device supports clipping using a list of clip +rectangles.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant></entry> + <entry>0x0008</entry> + <entry>The device supports clipping using a bit mask.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_LOCAL_ALPHA</constant></entry> + <entry>0x0010</entry> + <entry>The device supports clipping/blending using the +alpha channel of the framebuffer or VGA signal. Alpha blending makes +no sense for destructive overlays.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_GLOBAL_ALPHA</constant></entry> + <entry>0x0020</entry> + <entry>The device supports alpha blending using a global +alpha value. Alpha blending makes no sense for destructive overlays.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_CAP_LOCAL_INV_ALPHA</constant></entry> + <entry>0x0040</entry> + <entry>The device supports clipping/blending using the +inverted alpha channel of the framebuffer or VGA signal. Alpha +blending makes no sense for destructive overlays.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="framebuffer-flags"> + <title>Frame Buffer Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_FBUF_FLAG_PRIMARY</constant></entry> + <entry>0x0001</entry> + <entry>The framebuffer is the primary graphics surface. +In other words, the overlay is destructive. [?]</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_OVERLAY</constant></entry> + <entry>0x0002</entry> + <entry>The frame buffer is an overlay surface the same +size as the capture. [?]</entry> + </row> + <row> + <entry spanname="hspan">The purpose of +<constant>V4L2_FBUF_FLAG_PRIMARY</constant> and +<constant>V4L2_FBUF_FLAG_OVERLAY</constant> was never quite clear. +Most drivers seem to ignore these flags. For compatibility with the +<wordasword>bttv</wordasword> driver applications should set the +<constant>V4L2_FBUF_FLAG_OVERLAY</constant> flag.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_CHROMAKEY</constant></entry> + <entry>0x0004</entry> + <entry>Use chroma-keying. The chroma-key color is +determined by the <structfield>chromakey</structfield> field of +&v4l2-window; and negotiated with the &VIDIOC-S-FMT; ioctl, see <xref + linkend="overlay" /> +and + <xref linkend="osd" />.</entry> + </row> + <row> + <entry spanname="hspan">There are no flags to enable +clipping using a list of clip rectangles or a bitmap. These methods +are negotiated with the &VIDIOC-S-FMT; ioctl, see <xref + linkend="overlay" /> and <xref linkend="osd" />.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_LOCAL_ALPHA</constant></entry> + <entry>0x0008</entry> + <entry>Use the alpha channel of the framebuffer to clip or +blend framebuffer pixels with video images. The blend +function is: output = framebuffer pixel * alpha + video pixel * (1 - +alpha). The actual alpha depth depends on the framebuffer pixel +format.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_GLOBAL_ALPHA</constant></entry> + <entry>0x0010</entry> + <entry>Use a global alpha value to blend the framebuffer +with video images. The blend function is: output = (framebuffer pixel +* alpha + video pixel * (255 - alpha)) / 255. The alpha value is +determined by the <structfield>global_alpha</structfield> field of +&v4l2-window; and negotiated with the &VIDIOC-S-FMT; ioctl, see <xref + linkend="overlay" /> +and <xref linkend="osd" />.</entry> + </row> + <row> + <entry><constant>V4L2_FBUF_FLAG_LOCAL_INV_ALPHA</constant></entry> + <entry>0x0020</entry> + <entry>Like +<constant>V4L2_FBUF_FLAG_LOCAL_ALPHA</constant>, use the alpha channel +of the framebuffer to clip or blend framebuffer pixels with video +images, but with an inverted alpha value. The blend function is: +output = framebuffer pixel * (1 - alpha) + video pixel * alpha. The +actual alpha depth depends on the framebuffer pixel format.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EPERM</errorcode></term> + <listitem> + <para><constant>VIDIOC_S_FBUF</constant> can only be called +by a privileged user to negotiate the parameters for a destructive +overlay.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The framebuffer parameters cannot be changed at this +time because overlay is already enabled, or capturing is enabled +and the hardware cannot capture and overlay simultaneously.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The ioctl is not supported or the +<constant>VIDIOC_S_FBUF</constant> parameters are unsuitable.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-fmt.xml b/Documentation/DocBook/v4l/vidioc-g-fmt.xml new file mode 100644 index 0000000..7c7d1b7 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-fmt.xml @@ -0,0 +1,201 @@ +<refentry id="vidioc-g-fmt"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_FMT, VIDIOC_S_FMT, +VIDIOC_TRY_FMT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_FMT</refname> + <refname>VIDIOC_S_FMT</refname> + <refname>VIDIOC_TRY_FMT</refname> + <refpurpose>Get or set the data format, try a format</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_format +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_FMT, VIDIOC_S_FMT, VIDIOC_TRY_FMT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>These ioctls are used to negotiate the format of data +(typically image format) exchanged between driver and +application.</para> + + <para>To query the current parameters applications set the +<structfield>type</structfield> field of a struct +<structname>v4l2_format</structname> to the respective buffer (stream) +type. For example video capture devices use +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>. When the application +calls the <constant>VIDIOC_G_FMT</constant> ioctl with a pointer to +this structure the driver fills the respective member of the +<structfield>fmt</structfield> union. In case of video capture devices +that is the &v4l2-pix-format; <structfield>pix</structfield> member. +When the requested buffer type is not supported drivers return an +&EINVAL;.</para> + + <para>To change the current format parameters applications +initialize the <structfield>type</structfield> field and all +fields of the respective <structfield>fmt</structfield> +union member. For details see the documentation of the various devices +types in <xref linkend="devices" />. Good practice is to query the +current parameters first, and to +modify only those parameters not suitable for the application. When +the application calls the <constant>VIDIOC_S_FMT</constant> ioctl +with a pointer to a <structname>v4l2_format</structname> structure +the driver checks +and adjusts the parameters against hardware abilities. Drivers +should not return an error code unless the input is ambiguous, this is +a mechanism to fathom device capabilities and to approach parameters +acceptable for both the application and driver. On success the driver +may program the hardware, allocate resources and generally prepare for +data exchange. +Finally the <constant>VIDIOC_S_FMT</constant> ioctl returns the +current format parameters as <constant>VIDIOC_G_FMT</constant> does. +Very simple, inflexible devices may even ignore all input and always +return the default parameters. However all V4L2 devices exchanging +data with the application must implement the +<constant>VIDIOC_G_FMT</constant> and +<constant>VIDIOC_S_FMT</constant> ioctl. When the requested buffer +type is not supported drivers return an &EINVAL; on a +<constant>VIDIOC_S_FMT</constant> attempt. When I/O is already in +progress or the resource is not available for other reasons drivers +return the &EBUSY;.</para> + + <para>The <constant>VIDIOC_TRY_FMT</constant> ioctl is equivalent +to <constant>VIDIOC_S_FMT</constant> with one exception: it does not +change driver state. It can also be called at any time, never +returning <errorcode>EBUSY</errorcode>. This function is provided to +negotiate parameters, to learn about hardware limitations, without +disabling I/O or possibly time consuming hardware preparations. +Although strongly recommended drivers are not required to implement +this ioctl.</para> + + <table pgwide="1" frame="none" id="v4l2-format"> + <title>struct <structname>v4l2_format</structname></title> + <tgroup cols="4"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <tbody valign="top"> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>Type of the data stream, see <xref + linkend="v4l2-buf-type" />.</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield>fmt</structfield></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-pix-format;</entry> + <entry><structfield>pix</structfield></entry> + <entry>Definition of an image format, see <xref + linkend="pixfmt" />, used by video capture and output +devices.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-window;</entry> + <entry><structfield>win</structfield></entry> + <entry>Definition of an overlaid image, see <xref + linkend="overlay" />, used by video overlay devices.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-vbi-format;</entry> + <entry><structfield>vbi</structfield></entry> + <entry>Raw VBI capture or output parameters. This is +discussed in more detail in <xref linkend="raw-vbi" />. Used by raw VBI +capture and output devices.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-sliced-vbi-format;</entry> + <entry><structfield>sliced</structfield></entry> + <entry>Sliced VBI capture or output parameters. See +<xref linkend="sliced" /> for details. Used by sliced VBI +capture and output devices.</entry> + </row> + <row> + <entry></entry> + <entry>__u8</entry> + <entry><structfield>raw_data</structfield>[200]</entry> + <entry>Place holder for future extensions and custom +(driver defined) formats with <structfield>type</structfield> +<constant>V4L2_BUF_TYPE_PRIVATE</constant> and higher.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The data format cannot be changed at this +time, for example because I/O is already in progress.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-format; <structfield>type</structfield> +field is invalid, the requested buffer type not supported, or +<constant>VIDIOC_TRY_FMT</constant> was called and is not +supported with this buffer type.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-frequency.xml b/Documentation/DocBook/v4l/vidioc-g-frequency.xml new file mode 100644 index 0000000..062d720 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-frequency.xml @@ -0,0 +1,145 @@ +<refentry id="vidioc-g-frequency"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_FREQUENCY</refname> + <refname>VIDIOC_S_FREQUENCY</refname> + <refpurpose>Get or set tuner or modulator radio +frequency</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_frequency +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_frequency +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To get the current tuner or modulator radio frequency +applications set the <structfield>tuner</structfield> field of a +&v4l2-frequency; to the respective tuner or modulator number (only +input devices have tuners, only output devices have modulators), zero +out the <structfield>reserved</structfield> array and +call the <constant>VIDIOC_G_FREQUENCY</constant> ioctl with a pointer +to this structure. The driver stores the current frequency in the +<structfield>frequency</structfield> field.</para> + + <para>To change the current tuner or modulator radio frequency +applications initialize the <structfield>tuner</structfield>, +<structfield>type</structfield> and +<structfield>frequency</structfield> fields, and the +<structfield>reserved</structfield> array of a &v4l2-frequency; and +call the <constant>VIDIOC_S_FREQUENCY</constant> ioctl with a pointer +to this structure. When the requested frequency is not possible the +driver assumes the closest possible value. However +<constant>VIDIOC_S_FREQUENCY</constant> is a write-only ioctl, it does +not return the actual new frequency.</para> + + <table pgwide="1" frame="none" id="v4l2-frequency"> + <title>struct <structname>v4l2_frequency</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>tuner</structfield></entry> + <entry>The tuner or modulator index number. This is the +same value as in the &v4l2-input; <structfield>tuner</structfield> +field and the &v4l2-tuner; <structfield>index</structfield> field, or +the &v4l2-output; <structfield>modulator</structfield> field and the +&v4l2-modulator; <structfield>index</structfield> field.</entry> + </row> + <row> + <entry>&v4l2-tuner-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>The tuner type. This is the same value as in the +&v4l2-tuner; <structfield>type</structfield> field. The field is not +applicable to modulators, &ie; ignored by drivers.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>frequency</structfield></entry> + <entry>Tuning frequency in units of 62.5 kHz, or if the +&v4l2-tuner; or &v4l2-modulator; <structfield>capabilities</structfield> flag +<constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[8]</entry> + <entry>Reserved for future extensions. Drivers and + applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <structfield>tuner</structfield> index is out of +bounds or the value in the <structfield>type</structfield> field is +wrong.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-input.xml b/Documentation/DocBook/v4l/vidioc-g-input.xml new file mode 100644 index 0000000..ed076e9 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-input.xml @@ -0,0 +1,100 @@ +<refentry id="vidioc-g-input"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_INPUT</refname> + <refname>VIDIOC_S_INPUT</refname> + <refpurpose>Query or select the current video input</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>int *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_INPUT, VIDIOC_S_INPUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current video input applications call the +<constant>VIDIOC_G_INPUT</constant> ioctl with a pointer to an integer +where the driver stores the number of the input, as in the +&v4l2-input; <structfield>index</structfield> field. This ioctl will +fail only when there are no video inputs, returning +<errorcode>EINVAL</errorcode>.</para> + + <para>To select a video input applications store the number of the +desired input in an integer and call the +<constant>VIDIOC_S_INPUT</constant> ioctl with a pointer to this +integer. Side effects are possible. For example inputs may support +different video standards, so the driver may implicitly switch the +current standard. It is good practice to select an input before +querying or negotiating any other parameters.</para> + + <para>Information about video inputs is available using the +&VIDIOC-ENUMINPUT; ioctl.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the video input is out of bounds, or +there are no video inputs at all and this ioctl is not +supported.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>I/O is in progress, the input cannot be +switched.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml b/Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml new file mode 100644 index 0000000..77394b2 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml @@ -0,0 +1,180 @@ +<refentry id="vidioc-g-jpegcomp"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_JPEGCOMP</refname> + <refname>VIDIOC_S_JPEGCOMP</refname> + <refpurpose></refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>v4l2_jpegcompression *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const v4l2_jpegcompression *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>[to do]</para> + + <para>Ronald Bultje elaborates:</para> + + <!-- See video4linux-list@redhat.com on 16 Oct 2002, subject +"Re: [V4L] Re: v4l2 api / Zoran v4l2_jpegcompression" --> + + <para>APP is some application-specific information. The +application can set it itself, and it'll be stored in the JPEG-encoded +fields (eg; interlacing information for in an AVI or so). COM is the +same, but it's comments, like 'encoded by me' or so.</para> + + <para>jpeg_markers describes whether the huffman tables, +quantization tables and the restart interval information (all +JPEG-specific stuff) should be stored in the JPEG-encoded fields. +These define how the JPEG field is encoded. If you omit them, +applications assume you've used standard encoding. You usually do want +to add them.</para> + + <!-- NB VIDIOC_S_JPEGCOMP is w/o. --> + + <table pgwide="1" frame="none" id="v4l2-jpegcompression"> + <title>struct <structname>v4l2_jpegcompression</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>int</entry> + <entry><structfield>quality</structfield></entry> + <entry></entry> + </row> + <row> + <entry>int</entry> + <entry><structfield>APPn</structfield></entry> + <entry></entry> + </row> + <row> + <entry>int</entry> + <entry><structfield>APP_len</structfield></entry> + <entry></entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>APP_data</structfield>[60]</entry> + <entry></entry> + </row> + <row> + <entry>int</entry> + <entry><structfield>COM_len</structfield></entry> + <entry></entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>COM_data</structfield>[60]</entry> + <entry></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>jpeg_markers</structfield></entry> + <entry>See <xref linkend="jpeg-markers" />.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="jpeg-markers"> + <title>JPEG Markers Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_JPEG_MARKER_DHT</constant></entry> + <entry>(1<<3)</entry> + <entry>Define Huffman Tables</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_MARKER_DQT</constant></entry> + <entry>(1<<4)</entry> + <entry>Define Quantization Tables</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_MARKER_DRI</constant></entry> + <entry>(1<<5)</entry> + <entry>Define Restart Interval</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_MARKER_COM</constant></entry> + <entry>(1<<6)</entry> + <entry>Comment segment</entry> + </row> + <row> + <entry><constant>V4L2_JPEG_MARKER_APP</constant></entry> + <entry>(1<<7)</entry> + <entry>App segment, driver will always use APP0</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>This ioctl is not supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-modulator.xml b/Documentation/DocBook/v4l/vidioc-g-modulator.xml new file mode 100644 index 0000000..15ce660 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-modulator.xml @@ -0,0 +1,246 @@ +<refentry id="vidioc-g-modulator"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_MODULATOR</refname> + <refname>VIDIOC_S_MODULATOR</refname> + <refpurpose>Get or set modulator attributes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_modulator +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_modulator +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a modulator applications initialize +the <structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-modulator; and +call the <constant>VIDIOC_G_MODULATOR</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all modulators +applications shall begin at index zero, incrementing by one until the +driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>Modulators have two writable properties, an audio +modulation set and the radio frequency. To change the modulated audio +subprograms, applications initialize the <structfield>index +</structfield> and <structfield>txsubchans</structfield> fields and the +<structfield>reserved</structfield> array and call the +<constant>VIDIOC_S_MODULATOR</constant> ioctl. Drivers may choose a +different audio modulation if the request cannot be satisfied. However +this is a write-only ioctl, it does not return the actual audio +modulation selected.</para> + + <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl +is available.</para> + + <table pgwide="1" frame="none" id="v4l2-modulator"> + <title>struct <structname>v4l2_modulator</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the modulator, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the modulator, a NUL-terminated ASCII +string. This information is intended for the user.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>Modulator capability flags. No flags are defined +for this field, the tuner flags in &v4l2-tuner; +are used accordingly. The audio flags indicate the ability +to encode audio subprograms. They will <emphasis>not</emphasis> +change for example with the current video standard.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangelow</structfield></entry> + <entry>The lowest tunable frequency in units of 62.5 +KHz, or if the <structfield>capability</structfield> flag +<constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangehigh</structfield></entry> + <entry>The highest tunable frequency in units of 62.5 +KHz, or if the <structfield>capability</structfield> flag +<constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>txsubchans</structfield></entry> + <entry>With this field applications can determine how +audio sub-carriers shall be modulated. It contains a set of flags as +defined in <xref linkend="modulator-txsubchans" />. Note the tuner +<structfield>rxsubchans</structfield> flags are reused, but the +semantics are different. Video output devices are assumed to have an +analog or PCM audio input with 1-3 channels. The +<structfield>txsubchans</structfield> flags select one or more +channels for modulation, together with some audio subprogram +indicator, for example a stereo pilot tone.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="modulator-txsubchans"> + <title>Modulator Audio Transmission Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> + <entry>0x0001</entry> + <entry>Modulate channel 1 as mono audio, when the input +has more channels, a down-mix of channel 1 and 2. This flag does not +combine with <constant>V4L2_TUNER_SUB_STEREO</constant> or +<constant>V4L2_TUNER_SUB_LANG1</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_STEREO</constant></entry> + <entry>0x0002</entry> + <entry>Modulate channel 1 and 2 as left and right +channel of a stereo audio signal. When the input has only one channel +or two channels and <constant>V4L2_TUNER_SUB_SAP</constant> is also +set, channel 1 is encoded as left and right channel. This flag does +not combine with <constant>V4L2_TUNER_SUB_MONO</constant> or +<constant>V4L2_TUNER_SUB_LANG1</constant>. When the driver does not +support stereo audio it shall fall back to mono.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG1</constant></entry> + <entry>0x0008</entry> + <entry>Modulate channel 1 and 2 as primary and secondary +language of a bilingual audio signal. When the input has only one +channel it is used for both languages. It is not possible to encode +the primary or secondary language only. This flag does not combine +with <constant>V4L2_TUNER_SUB_MONO</constant>, +<constant>V4L2_TUNER_SUB_STEREO</constant> or +<constant>V4L2_TUNER_SUB_SAP</constant>. If the hardware does not +support the respective audio matrix, or the current video standard +does not permit bilingual audio the +<constant>VIDIOC_S_MODULATOR</constant> ioctl shall return an &EINVAL; +and the driver shall fall back to mono or stereo mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG2</constant></entry> + <entry>0x0004</entry> + <entry>Same effect as +<constant>V4L2_TUNER_SUB_SAP</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_SAP</constant></entry> + <entry>0x0004</entry> + <entry>When combined with <constant>V4L2_TUNER_SUB_MONO +</constant> the first channel is encoded as mono audio, the last +channel as Second Audio Program. When the input has only one channel +it is used for both audio tracks. When the input has three channels +the mono track is a down-mix of channel 1 and 2. When combined with +<constant>V4L2_TUNER_SUB_STEREO</constant> channel 1 and 2 are +encoded as left and right stereo audio, channel 3 as Second Audio +Program. When the input has only two channels, the first is encoded as +left and right channel and the second as SAP. When the input has only +one channel it is used for all audio tracks. It is not possible to +encode a Second Audio Program only. This flag must combine with +<constant>V4L2_TUNER_SUB_MONO</constant> or +<constant>V4L2_TUNER_SUB_STEREO</constant>. If the hardware does not +support the respective audio matrix, or the current video standard +does not permit SAP the <constant>VIDIOC_S_MODULATOR</constant> ioctl +shall return an &EINVAL; and driver shall fall back to mono or stereo +mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_RDS</constant></entry> + <entry>0x0010</entry> + <entry>Enable the RDS encoder for a radio FM transmitter.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-modulator; +<structfield>index</structfield> is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-output.xml b/Documentation/DocBook/v4l/vidioc-g-output.xml new file mode 100644 index 0000000..3ea8c0e --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-output.xml @@ -0,0 +1,100 @@ +<refentry id="vidioc-g-output"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_OUTPUT</refname> + <refname>VIDIOC_S_OUTPUT</refname> + <refpurpose>Query or select the current video output</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>int *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current video output applications call the +<constant>VIDIOC_G_OUTPUT</constant> ioctl with a pointer to an integer +where the driver stores the number of the output, as in the +&v4l2-output; <structfield>index</structfield> field. This ioctl +will fail only when there are no video outputs, returning the +&EINVAL;.</para> + + <para>To select a video output applications store the number of the +desired output in an integer and call the +<constant>VIDIOC_S_OUTPUT</constant> ioctl with a pointer to this integer. +Side effects are possible. For example outputs may support different +video standards, so the driver may implicitly switch the current +standard. It is good practice to select an output before querying or +negotiating any other parameters.</para> + + <para>Information about video outputs is available using the +&VIDIOC-ENUMOUTPUT; ioctl.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The number of the video output is out of bounds, or +there are no video outputs at all and this ioctl is not +supported.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>I/O is in progress, the output cannot be +switched.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-parm.xml b/Documentation/DocBook/v4l/vidioc-g-parm.xml new file mode 100644 index 0000000..78332d3 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-parm.xml @@ -0,0 +1,332 @@ +<refentry id="vidioc-g-parm"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_PARM, VIDIOC_S_PARM</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_PARM</refname> + <refname>VIDIOC_S_PARM</refname> + <refpurpose>Get or set streaming parameters</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>v4l2_streamparm *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_PARM, VIDIOC_S_PARM</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The current video standard determines a nominal number of +frames per second. If less than this number of frames is to be +captured or output, applications can request frame skipping or +duplicating on the driver side. This is especially useful when using +the <function>read()</function> or <function>write()</function>, which +are not augmented by timestamps or sequence counters, and to avoid +unneccessary data copying.</para> + + <para>Further these ioctls can be used to determine the number of +buffers used internally by a driver in read/write mode. For +implications see the section discussing the &func-read; +function.</para> + + <para>To get and set the streaming parameters applications call +the <constant>VIDIOC_G_PARM</constant> and +<constant>VIDIOC_S_PARM</constant> ioctl, respectively. They take a +pointer to a struct <structname>v4l2_streamparm</structname> which +contains a union holding separate parameters for input and output +devices.</para> + + <table pgwide="1" frame="none" id="v4l2-streamparm"> + <title>struct <structname>v4l2_streamparm</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry>The buffer (stream) type, same as &v4l2-format; +<structfield>type</structfield>, set by the application.</entry> + </row> + <row> + <entry>union</entry> + <entry><structfield>parm</structfield></entry> + <entry></entry> + <entry></entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-captureparm;</entry> + <entry><structfield>capture</structfield></entry> + <entry>Parameters for capture devices, used when +<structfield>type</structfield> is +<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>.</entry> + </row> + <row> + <entry></entry> + <entry>&v4l2-outputparm;</entry> + <entry><structfield>output</structfield></entry> + <entry>Parameters for output devices, used when +<structfield>type</structfield> is +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>.</entry> + </row> + <row> + <entry></entry> + <entry>__u8</entry> + <entry><structfield>raw_data</structfield>[200]</entry> + <entry>A place holder for future extensions and custom +(driver defined) buffer types <constant>V4L2_BUF_TYPE_PRIVATE</constant> and +higher.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-captureparm"> + <title>struct <structname>v4l2_captureparm</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>See <xref linkend="parm-caps" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capturemode</structfield></entry> + <entry>Set by drivers and applications, see <xref linkend="parm-flags" />.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>timeperframe</structfield></entry> + <entry><para>This is is the desired period between +successive frames captured by the driver, in seconds. The +field is intended to skip frames on the driver side, saving I/O +bandwidth.</para><para>Applications store here the desired frame +period, drivers return the actual frame period, which must be greater +or equal to the nominal frame period determined by the current video +standard (&v4l2-standard; <structfield>frameperiod</structfield> +field). Changing the video standard (also implicitly by switching the +video input) may reset this parameter to the nominal frame period. To +reset manually applications can just set this field to +zero.</para><para>Drivers support this function only when they set the +<constant>V4L2_CAP_TIMEPERFRAME</constant> flag in the +<structfield>capability</structfield> field.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>extendedmode</structfield></entry> + <entry>Custom (driver specific) streaming parameters. When +unused, applications and drivers must set this field to zero. +Applications using this field should check the driver name and +version, see <xref linkend="querycap" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>readbuffers</structfield></entry> + <entry>Applications set this field to the desired number +of buffers used internally by the driver in &func-read; mode. Drivers +return the actual number of buffers. When an application requests zero +buffers, drivers should just return the current setting rather than +the minimum or an error code. For details see <xref + linkend="rw" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-outputparm"> + <title>struct <structname>v4l2_outputparm</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>See <xref linkend="parm-caps" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>outputmode</structfield></entry> + <entry>Set by drivers and applications, see <xref + linkend="parm-flags" />.</entry> + </row> + <row> + <entry>&v4l2-fract;</entry> + <entry><structfield>timeperframe</structfield></entry> + <entry>This is is the desired period between +successive frames output by the driver, in seconds.</entry> + </row> + <row> + <entry spanname="hspan"><para>The field is intended to +repeat frames on the driver side in &func-write; mode (in streaming +mode timestamps can be used to throttle the output), saving I/O +bandwidth.</para><para>Applications store here the desired frame +period, drivers return the actual frame period, which must be greater +or equal to the nominal frame period determined by the current video +standard (&v4l2-standard; <structfield>frameperiod</structfield> +field). Changing the video standard (also implicitly by switching the +video output) may reset this parameter to the nominal frame period. To +reset manually applications can just set this field to +zero.</para><para>Drivers support this function only when they set the +<constant>V4L2_CAP_TIMEPERFRAME</constant> flag in the +<structfield>capability</structfield> field.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>extendedmode</structfield></entry> + <entry>Custom (driver specific) streaming parameters. When +unused, applications and drivers must set this field to zero. +Applications using this field should check the driver name and +version, see <xref linkend="querycap" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>writebuffers</structfield></entry> + <entry>Applications set this field to the desired number +of buffers used internally by the driver in +<function>write()</function> mode. Drivers return the actual number of +buffers. When an application requests zero buffers, drivers should +just return the current setting rather than the minimum or an error +code. For details see <xref linkend="rw" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="parm-caps"> + <title>Streaming Parameters Capabilites</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CAP_TIMEPERFRAME</constant></entry> + <entry>0x1000</entry> + <entry>The frame skipping/repeating controlled by the +<structfield>timeperframe</structfield> field is supported.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="parm-flags"> + <title>Capture Parameters Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_MODE_HIGHQUALITY</constant></entry> + <entry>0x0001</entry> + <entry><para>High quality imaging mode. High quality mode +is intended for still imaging applications. The idea is to get the +best possible image quality that the hardware can deliver. It is not +defined how the driver writer may achieve that; it will depend on the +hardware and the ingenuity of the driver writer. High quality mode is +a different mode from the the regular motion video capture modes. In +high quality mode:<itemizedlist> + <listitem> + <para>The driver may be able to capture higher +resolutions than for motion capture.</para> + </listitem> + <listitem> + <para>The driver may support fewer pixel formats +than motion capture (eg; true color).</para> + </listitem> + <listitem> + <para>The driver may capture and arithmetically +combine multiple successive fields or frames to remove color edge +artifacts and reduce the noise in the video data. +</para> + </listitem> + <listitem> + <para>The driver may capture images in slices like +a scanner in order to handle larger format images than would otherwise +be possible. </para> + </listitem> + <listitem> + <para>An image capture operation may be +significantly slower than motion capture. </para> + </listitem> + <listitem> + <para>Moving objects in the image might have +excessive motion blur. </para> + </listitem> + <listitem> + <para>Capture might only work through the +<function>read()</function> call.</para> + </listitem> + </itemizedlist></para></entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>This ioctl is not supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-priority.xml b/Documentation/DocBook/v4l/vidioc-g-priority.xml new file mode 100644 index 0000000..5fb0019 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-priority.xml @@ -0,0 +1,144 @@ +<refentry id="vidioc-g-priority"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_PRIORITY, VIDIOC_S_PRIORITY</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_PRIORITY</refname> + <refname>VIDIOC_S_PRIORITY</refname> + <refpurpose>Query or request the access priority associated with a +file descriptor</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>enum v4l2_priority *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const enum v4l2_priority *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_PRIORITY, VIDIOC_S_PRIORITY</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to an enum v4l2_priority type.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current access priority +applications call the <constant>VIDIOC_G_PRIORITY</constant> ioctl +with a pointer to an enum v4l2_priority variable where the driver stores +the current priority.</para> + + <para>To request an access priority applications store the +desired priority in an enum v4l2_priority variable and call +<constant>VIDIOC_S_PRIORITY</constant> ioctl with a pointer to this +variable.</para> + + <table frame="none" pgwide="1" id="v4l2-priority"> + <title>enum v4l2_priority</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_PRIORITY_UNSET</constant></entry> + <entry>0</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_PRIORITY_BACKGROUND</constant></entry> + <entry>1</entry> + <entry>Lowest priority, usually applications running in +background, for example monitoring VBI transmissions. A proxy +application running in user space will be necessary if multiple +applications want to read from a device at this priority.</entry> + </row> + <row> + <entry><constant>V4L2_PRIORITY_INTERACTIVE</constant></entry> + <entry>2</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_PRIORITY_DEFAULT</constant></entry> + <entry>2</entry> + <entry>Medium priority, usually applications started and +interactively controlled by the user. For example TV viewers, Teletext +browsers, or just "panel" applications to change the channel or video +controls. This is the default priority unless an application requests +another.</entry> + </row> + <row> + <entry><constant>V4L2_PRIORITY_RECORD</constant></entry> + <entry>3</entry> + <entry>Highest priority. Only one file descriptor can have +this priority, it blocks any other fd from changing device properties. +Usually applications which must not be interrupted, like video +recording.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The requested priority value is invalid, or the +driver does not support access priorities.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>Another application already requested higher +priority.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-sliced-vbi-cap.xml b/Documentation/DocBook/v4l/vidioc-g-sliced-vbi-cap.xml new file mode 100644 index 0000000..10e721b --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-sliced-vbi-cap.xml @@ -0,0 +1,264 @@ +<refentry id="vidioc-g-sliced-vbi-cap"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_SLICED_VBI_CAP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_SLICED_VBI_CAP</refname> + <refpurpose>Query sliced VBI capabilities</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_sliced_vbi_cap *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_SLICED_VBI_CAP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To find out which data services are supported by a sliced +VBI capture or output device, applications initialize the +<structfield>type</structfield> field of a &v4l2-sliced-vbi-cap;, +clear the <structfield>reserved</structfield> array and +call the <constant>VIDIOC_G_SLICED_VBI_CAP</constant> ioctl. The +driver fills in the remaining fields or returns an &EINVAL; if the +sliced VBI API is unsupported or <structfield>type</structfield> +is invalid.</para> + + <para>Note the <structfield>type</structfield> field was added, +and the ioctl changed from read-only to write-read, in Linux 2.6.19.</para> + + <table pgwide="1" frame="none" id="v4l2-sliced-vbi-cap"> + <title>struct <structname>v4l2_sliced_vbi_cap</structname></title> + <tgroup cols="5"> + <colspec colname="c1" colwidth="3*" /> + <colspec colname="c2" colwidth="3*" /> + <colspec colname="c3" colwidth="2*" /> + <colspec colname="c4" colwidth="2*" /> + <colspec colname="c5" colwidth="2*" /> + <spanspec spanname="hspan" namest="c3" nameend="c5" /> + <tbody valign="top"> + <row> + <entry>__u16</entry> + <entry><structfield>service_set</structfield></entry> + <entry spanname="hspan">A set of all data services +supported by the driver. Equal to the union of all elements of the +<structfield>service_lines </structfield> array.</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>service_lines</structfield>[2][24]</entry> + <entry spanname="hspan">Each element of this array +contains a set of data services the hardware can look for or insert +into a particular scan line. Data services are defined in <xref + linkend="vbi-services" />. Array indices map to ITU-R +line numbers (see also <xref + linkend="vbi-525" /> and <xref +linkend="vbi-625" />) as follows:</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>Element</entry> + <entry>525 line systems</entry> + <entry>625 line systems</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[0][1]</entry> + <entry align="center">1</entry> + <entry align="center">1</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[0][23]</entry> + <entry align="center">23</entry> + <entry align="center">23</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[1][1]</entry> + <entry align="center">264</entry> + <entry align="center">314</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><structfield>service_lines</structfield>[1][23]</entry> + <entry align="center">286</entry> + <entry align="center">336</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan">The number of VBI lines the +hardware can capture or output per frame, or the number of services it +can identify on a given line may be limited. For example on PAL line +16 the hardware may be able to look for a VPS or Teletext signal, but +not both at the same time. Applications can learn about these limits +using the &VIDIOC-S-FMT; ioctl as described in <xref + linkend="sliced" />.</entry> + </row> + <row> + <entry></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan">Drivers must set +<structfield>service_lines</structfield>[0][0] and +<structfield>service_lines</structfield>[1][0] to zero.</entry> + </row> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the data stream, see <xref + linkend="v4l2-buf-type" />. Should be +<constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> or +<constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[3]</entry> + <entry spanname="hspan">This array is reserved for future +extensions. Applications and drivers must set it to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- See also dev-sliced-vbi.sgml --> + <table pgwide="1" frame="none" id="vbi-services"> + <title>Sliced VBI services</title> + <tgroup cols="5"> + <colspec colname="c1" colwidth="2*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="1*" /> + <colspec colname="c4" colwidth="2*" /> + <colspec colname="c5" colwidth="2*" /> + <spanspec spanname='rlp' namest='c3' nameend='c5' /> + <thead> + <row> + <entry>Symbol</entry> + <entry>Value</entry> + <entry>Reference</entry> + <entry>Lines, usually</entry> + <entry>Payload</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_SLICED_TELETEXT_B</constant> (Teletext +System B)</entry> + <entry>0x0001</entry> + <entry><xref linkend="ets300706" />, <xref linkend="itu653" /></entry> + <entry>PAL/SECAM line 7-22, 320-335 (second field 7-22)</entry> + <entry>Last 42 of the 45 byte Teletext packet, that is +without clock run-in and framing code, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VPS</constant></entry> + <entry>0x0400</entry> + <entry><xref linkend="ets300231" /></entry> + <entry>PAL line 16</entry> + <entry>Byte number 3 to 15 according to Figure 9 of +ETS 300 231, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_CAPTION_525</constant></entry> + <entry>0x1000</entry> + <entry><xref linkend="eia608" /></entry> + <entry>NTSC line 21, 284 (second field 21)</entry> + <entry>Two bytes in transmission order, including parity +bit, lsb first transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_WSS_625</constant></entry> + <entry>0x4000</entry> + <entry><xref linkend="en300294" />, <xref linkend="itu1119" /></entry> + <entry>PAL/SECAM line 23</entry> + <entry><screen> +Byte 0 1 + msb lsb msb lsb +Bit 7 6 5 4 3 2 1 0 x x 13 12 11 10 9 +</screen></entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VBI_525</constant></entry> + <entry>0x1000</entry> + <entry spanname="rlp">Set of services applicable to 525 +line systems.</entry> + </row> + <row> + <entry><constant>V4L2_SLICED_VBI_625</constant></entry> + <entry>0x4401</entry> + <entry spanname="rlp">Set of services applicable to 625 +line systems.</entry> + </row> + </tbody> + </tgroup> + </table> + + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The device does not support sliced VBI capturing or +output, or the value in the <structfield>type</structfield> field is +wrong.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-std.xml b/Documentation/DocBook/v4l/vidioc-g-std.xml new file mode 100644 index 0000000..b6f5d26 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-std.xml @@ -0,0 +1,99 @@ +<refentry id="vidioc-g-std"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_STD, VIDIOC_S_STD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_STD</refname> + <refname>VIDIOC_S_STD</refname> + <refpurpose>Query or select the video standard of the current input</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>v4l2_std_id +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const v4l2_std_id +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_STD, VIDIOC_S_STD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query and select the current video standard applications +use the <constant>VIDIOC_G_STD</constant> and <constant>VIDIOC_S_STD</constant> ioctls which take a pointer to a +&v4l2-std-id; type as argument. <constant>VIDIOC_G_STD</constant> can +return a single flag or a set of flags as in &v4l2-standard; field +<structfield>id</structfield>. The flags must be unambiguous such +that they appear in only one enumerated <structname>v4l2_standard</structname> structure.</para> + + <para><constant>VIDIOC_S_STD</constant> accepts one or more +flags, being a write-only ioctl it does not return the actual new standard as +<constant>VIDIOC_G_STD</constant> does. When no flags are given or +the current input does not support the requested standard the driver +returns an &EINVAL;. When the standard set is ambiguous drivers may +return <errorcode>EINVAL</errorcode> or choose any of the requested +standards.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>This ioctl is not supported, or the +<constant>VIDIOC_S_STD</constant> parameter was unsuitable.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-g-tuner.xml b/Documentation/DocBook/v4l/vidioc-g-tuner.xml new file mode 100644 index 0000000..bd98c73 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-tuner.xml @@ -0,0 +1,535 @@ +<refentry id="vidioc-g-tuner"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_TUNER, VIDIOC_S_TUNER</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_TUNER</refname> + <refname>VIDIOC_S_TUNER</refname> + <refpurpose>Get or set tuner attributes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_tuner +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_tuner +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_TUNER, VIDIOC_S_TUNER</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a tuner applications initialize the +<structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-tuner; and call the +<constant>VIDIOC_G_TUNER</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all tuners +applications shall begin at index zero, incrementing by one until the +driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>Tuners have two writable properties, the audio mode and +the radio frequency. To change the audio mode, applications initialize +the <structfield>index</structfield>, +<structfield>audmode</structfield> and +<structfield>reserved</structfield> fields and call the +<constant>VIDIOC_S_TUNER</constant> ioctl. This will +<emphasis>not</emphasis> change the current tuner, which is determined +by the current video input. Drivers may choose a different audio mode +if the requested mode is invalid or unsupported. Since this is a +<!-- FIXME -->write-only ioctl, it does not return the actually +selected audio mode.</para> + + <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl +is available.</para> + + <table pgwide="1" frame="none" id="v4l2-tuner"> + <title>struct <structname>v4l2_tuner</structname></title> + <tgroup cols="3"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="1*" /> + <colspec colname="c4" colwidth="1*" /> + <spanspec spanname="hspan" namest="c3" nameend="c4" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry spanname="hspan">Identifies the tuner, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry spanname="hspan"><para>Name of the tuner, a +NUL-terminated ASCII string. This information is intended for the +user.<!-- FIXME Video inputs already have a name, the purpose of this +field is not quite clear.--></para></entry> + </row> + <row> + <entry>&v4l2-tuner-type;</entry> + <entry><structfield>type</structfield></entry> + <entry spanname="hspan">Type of the tuner, see <xref + linkend="v4l2-tuner-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry spanname="hspan"><para>Tuner capability flags, see +<xref linkend="tuner-capability" />. Audio flags indicate the ability +to decode audio subprograms. They will <emphasis>not</emphasis> +change, for example with the current video standard.</para><para>When +the structure refers to a radio tuner only the +<constant>V4L2_TUNER_CAP_LOW</constant>, +<constant>V4L2_TUNER_CAP_STEREO</constant> and +<constant>V4L2_TUNER_CAP_RDS</constant> flags can be set.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangelow</structfield></entry> + <entry spanname="hspan">The lowest tunable frequency in +units of 62.5 kHz, or if the <structfield>capability</structfield> +flag <constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangehigh</structfield></entry> + <entry spanname="hspan">The highest tunable frequency in +units of 62.5 kHz, or if the <structfield>capability</structfield> +flag <constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rxsubchans</structfield></entry> + <entry spanname="hspan"><para>Some tuners or audio +decoders can determine the received audio subprograms by analyzing +audio carriers, pilot tones or other indicators. To pass this +information drivers set flags defined in <xref + linkend="tuner-rxsubchans" /> in this field. For +example:</para></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> + <entry>receiving mono audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>STEREO | SAP</constant></entry> + <entry>receiving stereo audio and a secondary audio +program</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>MONO | STEREO</constant></entry> + <entry>receiving mono or stereo audio, the hardware cannot +distinguish</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>LANG1 | LANG2</constant></entry> + <entry>receiving bilingual audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>MONO | STEREO | LANG1 | LANG2</constant></entry> + <entry>receiving mono, stereo or bilingual +audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan"><para>When the +<constant>V4L2_TUNER_CAP_STEREO</constant>, +<constant>_LANG1</constant>, <constant>_LANG2</constant> or +<constant>_SAP</constant> flag is cleared in the +<structfield>capability</structfield> field, the corresponding +<constant>V4L2_TUNER_SUB_</constant> flag must not be set +here.</para><para>This field is valid only if this is the tuner of the +current video input, or when the structure refers to a radio +tuner.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>audmode</structfield></entry> + <entry spanname="hspan"><para>The selected audio mode, see +<xref linkend="tuner-audmode" /> for valid values. The audio mode does +not affect audio subprogram detection, and like a <link +linkend="control">control</link> it does not automatically change +unless the requested mode is invalid or unsupported. See <xref + linkend="tuner-matrix" /> for possible results when +the selected and received audio programs do not +match.</para><para>Currently this is the only field of struct +<structname>v4l2_tuner</structname> applications can +change.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>signal</structfield></entry> + <entry spanname="hspan">The signal strength if known, ranging +from 0 to 65535. Higher values indicate a better signal.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>afc</structfield></entry> + <entry spanname="hspan">Automatic frequency control: When the +<structfield>afc</structfield> value is negative, the frequency is too +low, when positive too high.<!-- FIXME need example what to do when it never +settles at zero, &ie; range is what? --></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry spanname="hspan">Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-tuner-type"> + <title>enum v4l2_tuner_type</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_RADIO</constant></entry> + <entry>1</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_ANALOG_TV</constant></entry> + <entry>2</entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-capability"> + <title>Tuner and Modulator Capability Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_CAP_LOW</constant></entry> + <entry>0x0001</entry> + <entry>When set, tuning frequencies are expressed in units of +62.5 Hz, otherwise in units of 62.5 kHz.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_NORM</constant></entry> + <entry>0x0002</entry> + <entry>This is a multi-standard tuner; the video standard +can or must be switched. (B/G PAL tuners for example are typically not + considered multi-standard because the video standard is automatically + determined from the frequency band.) The set of supported video + standards is available from the &v4l2-input; pointing to this tuner, + see the description of ioctl &VIDIOC-ENUMINPUT; for details. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_STEREO</constant></entry> + <entry>0x0010</entry> + <entry>Stereo audio reception is supported.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_LANG1</constant></entry> + <entry>0x0040</entry> + <entry>Reception of the primary language of a bilingual +audio program is supported. Bilingual audio is a feature of +two-channel systems, transmitting the primary language monaural on the +main audio carrier and a secondary language monaural on a second +carrier. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_LANG2</constant></entry> + <entry>0x0020</entry> + <entry>Reception of the secondary language of a bilingual +audio program is supported. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_SAP</constant></entry> + <entry>0x0020</entry> + <entry><para>Reception of a secondary audio program is +supported. This is a feature of the BTSC system which accompanies the +NTSC video standard. Two audio carriers are available for mono or +stereo transmissions of a primary language, and an independent third +carrier for a monaural secondary language. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</para><para>Note the +<constant>V4L2_TUNER_CAP_LANG2</constant> and +<constant>V4L2_TUNER_CAP_SAP</constant> flags are synonyms. +<constant>V4L2_TUNER_CAP_SAP</constant> applies when the tuner +supports the <constant>V4L2_STD_NTSC_M</constant> video +standard.</para><!-- FIXME what if PAL+NTSC and Bi but not SAP? --></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_RDS</constant></entry> + <entry>0x0080</entry> + <entry>RDS capture is supported. This capability is only valid for +radio tuners.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-rxsubchans"> + <title>Tuner Audio Reception Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> + <entry>0x0001</entry> + <entry>The tuner receives a mono audio signal.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_STEREO</constant></entry> + <entry>0x0002</entry> + <entry>The tuner receives a stereo audio signal.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG1</constant></entry> + <entry>0x0008</entry> + <entry>The tuner receives the primary language of a +bilingual audio signal. Drivers must clear this flag when the current +video standard is <constant>V4L2_STD_NTSC_M</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG2</constant></entry> + <entry>0x0004</entry> + <entry>The tuner receives the secondary language of a +bilingual audio signal (or a second audio program).</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_SAP</constant></entry> + <entry>0x0004</entry> + <entry>The tuner receives a Second Audio Program. Note the +<constant>V4L2_TUNER_SUB_LANG2</constant> and +<constant>V4L2_TUNER_SUB_SAP</constant> flags are synonyms. The +<constant>V4L2_TUNER_SUB_SAP</constant> flag applies when the +current video standard is <constant>V4L2_STD_NTSC_M</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_RDS</constant></entry> + <entry>0x0010</entry> + <entry>The tuner receives an RDS channel.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-audmode"> + <title>Tuner Audio Modes</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_MODE_MONO</constant></entry> + <entry>0</entry> + <entry>Play mono audio. When the tuner receives a stereo +signal this a down-mix of the left and right channel. When the tuner +receives a bilingual or SAP signal this mode selects the primary +language.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_STEREO</constant></entry> + <entry>1</entry> + <entry><para>Play stereo audio. When the tuner receives +bilingual audio it may play different languages on the left and right +channel or the primary language is played on both channels.</para><para>Playing +different languages in this mode is +deprecated. New drivers should do this only in +<constant>MODE_LANG1_LANG2</constant>.</para><para>When the tuner +receives no stereo signal or does not support stereo reception the +driver shall fall back to <constant>MODE_MONO</constant>.</para></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG1</constant></entry> + <entry>3</entry> + <entry>Play the primary language, mono or stereo. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG2</constant></entry> + <entry>2</entry> + <entry>Play the secondary language, mono. When the tuner +receives no bilingual audio or SAP, or their reception is not +supported the driver shall fall back to mono or stereo mode. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_SAP</constant></entry> + <entry>2</entry> + <entry>Play the Second Audio Program. When the tuner +receives no bilingual audio or SAP, or their reception is not +supported the driver shall fall back to mono or stereo mode. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this mode. +Note the <constant>V4L2_TUNER_MODE_LANG2</constant> and +<constant>V4L2_TUNER_MODE_SAP</constant> are synonyms.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG1_LANG2</constant></entry> + <entry>4</entry> + <entry>Play the primary language on the left channel, the +secondary language on the right channel. When the tuner receives no +bilingual audio or SAP, it shall fall back to +<constant>MODE_LANG1</constant> or <constant>MODE_MONO</constant>. +Only <constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="all" id="tuner-matrix"> + <title>Tuner Audio Matrix</title> + <tgroup cols="6" align="center"> + <colspec align="left" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colwidth="1*" /> + <colspec colwidth="1*" /> + <colspec colnum="6" colname="c6" colwidth="1*" /> + <spanspec namest="c2" nameend="c6" spanname="hspan" align="center" /> + <thead> + <row> + <entry></entry> + <entry spanname="hspan">Selected +<constant>V4L2_TUNER_MODE_</constant></entry> + </row> + <row> + <entry>Received <constant>V4L2_TUNER_SUB_</constant></entry> + <entry><constant>MONO</constant></entry> + <entry><constant>STEREO</constant></entry> + <entry><constant>LANG1</constant></entry> + <entry><constant>LANG2 = SAP</constant></entry> + <entry><constant>LANG1_LANG2</constant><footnote><para>This +mode has been added in Linux 2.6.17 and may not be supported by older +drivers.</para></footnote></entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>MONO</constant></entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + <entry>Mono</entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + </row> + <row> + <entry><constant>MONO | SAP</constant></entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + <entry>Mono</entry> + <entry>SAP</entry> + <entry>Mono/SAP (preferred) or Mono/Mono</entry> + </row> + <row> + <entry><constant>STEREO</constant></entry> + <entry>L+R</entry> + <entry>L/R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>L/R (preferred) or L+R/L+R</entry> + </row> + <row> + <entry><constant>STEREO | SAP</constant></entry> + <entry>L+R</entry> + <entry>L/R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>SAP</entry> + <entry>L+R/SAP (preferred) or L/R or L+R/L+R</entry> + </row> + <row> + <entry><constant>LANG1 | LANG2</constant></entry> + <entry>Language 1</entry> + <entry>Lang1/Lang2 (deprecated<footnote><para>Playback of +both languages in <constant>MODE_STEREO</constant> is deprecated. In +the future drivers should produce only the primary language in this +mode. Applications should request +<constant>MODE_LANG1_LANG2</constant> to record both languages or a +stereo signal.</para></footnote>) or +Lang1/Lang1</entry> + <entry>Language 1</entry> + <entry>Language 2</entry> + <entry>Lang1/Lang2 (preferred) or Lang1/Lang1</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-tuner; <structfield>index</structfield> is +out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-log-status.xml b/Documentation/DocBook/v4l/vidioc-log-status.xml new file mode 100644 index 0000000..2634b7c --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-log-status.xml @@ -0,0 +1,58 @@ +<refentry id="vidioc-log-status"> + <refmeta> + <refentrytitle>ioctl VIDIOC_LOG_STATUS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_LOG_STATUS</refname> + <refpurpose>Log driver status information</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>As the video/audio devices become more complicated it +becomes harder to debug problems. When this ioctl is called the driver +will output the current device status to the kernel log. This is +particular useful when dealing with problems like no sound, no video +and incorrectly tuned channels. Also many modern devices autodetect +video and audio standards and this ioctl will report what the device +thinks what the standard is. Mismatches may give an indication where +the problem is.</para> + + <para>This ioctl is optional and not all drivers support it. It +was introduced in Linux 2.6.15.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The driver does not support this ioctl.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-overlay.xml b/Documentation/DocBook/v4l/vidioc-overlay.xml new file mode 100644 index 0000000..1036c58 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-overlay.xml @@ -0,0 +1,83 @@ +<refentry id="vidioc-overlay"> + <refmeta> + <refentrytitle>ioctl VIDIOC_OVERLAY</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_OVERLAY</refname> + <refpurpose>Start or stop video overlay</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const int *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_OVERLAY</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl is part of the <link linkend="overlay">video + overlay</link> I/O method. Applications call + <constant>VIDIOC_OVERLAY</constant> to start or stop the + overlay. It takes a pointer to an integer which must be set to + zero by the application to stop overlay, to one to start.</para> + + <para>Drivers do not support &VIDIOC-STREAMON; or +&VIDIOC-STREAMOFF; with <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>Video overlay is not supported, or the +parameters have not been set up. See <xref +linkend="overlay" /> for the necessary steps.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-qbuf.xml b/Documentation/DocBook/v4l/vidioc-qbuf.xml new file mode 100644 index 0000000..1870817 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-qbuf.xml @@ -0,0 +1,168 @@ +<refentry id="vidioc-qbuf"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QBUF, VIDIOC_DQBUF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QBUF</refname> + <refname>VIDIOC_DQBUF</refname> + <refpurpose>Exchange a buffer with the driver</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_buffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QBUF, VIDIOC_DQBUF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Applications call the <constant>VIDIOC_QBUF</constant> ioctl +to enqueue an empty (capturing) or filled (output) buffer in the +driver's incoming queue. The semantics depend on the selected I/O +method.</para> + + <para>To enqueue a <link linkend="mmap">memory mapped</link> +buffer applications set the <structfield>type</structfield> field of a +&v4l2-buffer; to the same buffer type as previously &v4l2-format; +<structfield>type</structfield> and &v4l2-requestbuffers; +<structfield>type</structfield>, the <structfield>memory</structfield> +field to <constant>V4L2_MEMORY_MMAP</constant> and the +<structfield>index</structfield> field. Valid index numbers range from +zero to the number of buffers allocated with &VIDIOC-REQBUFS; +(&v4l2-requestbuffers; <structfield>count</structfield>) minus one. The +contents of the struct <structname>v4l2_buffer</structname> returned +by a &VIDIOC-QUERYBUF; ioctl will do as well. When the buffer is +intended for output (<structfield>type</structfield> is +<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> or +<constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>) applications must also +initialize the <structfield>bytesused</structfield>, +<structfield>field</structfield> and +<structfield>timestamp</structfield> fields. See <xref + linkend="buffer" /> for details. When +<constant>VIDIOC_QBUF</constant> is called with a pointer to this +structure the driver sets the +<constant>V4L2_BUF_FLAG_MAPPED</constant> and +<constant>V4L2_BUF_FLAG_QUEUED</constant> flags and clears the +<constant>V4L2_BUF_FLAG_DONE</constant> flag in the +<structfield>flags</structfield> field, or it returns an +&EINVAL;.</para> + + <para>To enqueue a <link linkend="userp">user pointer</link> +buffer applications set the <structfield>type</structfield> field of a +&v4l2-buffer; to the same buffer type as previously &v4l2-format; +<structfield>type</structfield> and &v4l2-requestbuffers; +<structfield>type</structfield>, the <structfield>memory</structfield> +field to <constant>V4L2_MEMORY_USERPTR</constant> and the +<structfield>m.userptr</structfield> field to the address of the +buffer and <structfield>length</structfield> to its size. When the +buffer is intended for output additional fields must be set as above. +When <constant>VIDIOC_QBUF</constant> is called with a pointer to this +structure the driver sets the <constant>V4L2_BUF_FLAG_QUEUED</constant> +flag and clears the <constant>V4L2_BUF_FLAG_MAPPED</constant> and +<constant>V4L2_BUF_FLAG_DONE</constant> flags in the +<structfield>flags</structfield> field, or it returns an error code. +This ioctl locks the memory pages of the buffer in physical memory, +they cannot be swapped out to disk. Buffers remain locked until +dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl are +called, or until the device is closed.</para> + + <para>Applications call the <constant>VIDIOC_DQBUF</constant> +ioctl to dequeue a filled (capturing) or displayed (output) buffer +from the driver's outgoing queue. They just set the +<structfield>type</structfield> and <structfield>memory</structfield> +fields of a &v4l2-buffer; as above, when <constant>VIDIOC_DQBUF</constant> +is called with a pointer to this structure the driver fills the +remaining fields or returns an error code.</para> + + <para>By default <constant>VIDIOC_DQBUF</constant> blocks when no +buffer is in the outgoing queue. When the +<constant>O_NONBLOCK</constant> flag was given to the &func-open; +function, <constant>VIDIOC_DQBUF</constant> returns immediately +with an &EAGAIN; when no buffer is available.</para> + + <para>The <structname>v4l2_buffer</structname> structure is +specified in <xref linkend="buffer" />.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EAGAIN</errorcode></term> + <listitem> + <para>Non-blocking I/O has been selected using +<constant>O_NONBLOCK</constant> and no buffer was in the outgoing +queue.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer <structfield>type</structfield> is not +supported, or the <structfield>index</structfield> is out of bounds, +or no buffers have been allocated yet, or the +<structfield>userptr</structfield> or +<structfield>length</structfield> are invalid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Not enough physical or virtual memory was available to +enqueue a user pointer buffer.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EIO</errorcode></term> + <listitem> + <para><constant>VIDIOC_DQBUF</constant> failed due to an +internal error. Can also indicate temporary problems like signal +loss. Note the driver might dequeue an (empty) buffer despite +returning an error, or even stop capturing.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-querybuf.xml b/Documentation/DocBook/v4l/vidioc-querybuf.xml new file mode 100644 index 0000000..d834993 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-querybuf.xml @@ -0,0 +1,103 @@ +<refentry id="vidioc-querybuf"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERYBUF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERYBUF</refname> + <refpurpose>Query the status of a buffer</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_buffer *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERYBUF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl is part of the <link linkend="mmap">memory +mapping</link> I/O method. It can be used to query the status of a +buffer at any time after buffers have been allocated with the +&VIDIOC-REQBUFS; ioctl.</para> + + <para>Applications set the <structfield>type</structfield> field + of a &v4l2-buffer; to the same buffer type as previously +&v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers; +<structfield>type</structfield>, and the <structfield>index</structfield> + field. Valid index numbers range from zero +to the number of buffers allocated with &VIDIOC-REQBUFS; + (&v4l2-requestbuffers; <structfield>count</structfield>) minus one. +After calling <constant>VIDIOC_QUERYBUF</constant> with a pointer to + this structure drivers return an error code or fill the rest of +the structure.</para> + + <para>In the <structfield>flags</structfield> field the +<constant>V4L2_BUF_FLAG_MAPPED</constant>, +<constant>V4L2_BUF_FLAG_QUEUED</constant> and +<constant>V4L2_BUF_FLAG_DONE</constant> flags will be valid. The +<structfield>memory</structfield> field will be set to +<constant>V4L2_MEMORY_MMAP</constant>, the <structfield>m.offset</structfield> +contains the offset of the buffer from the start of the device memory, +the <structfield>length</structfield> field its size. The driver may +or may not set the remaining fields and flags, they are meaningless in +this context.</para> + + <para>The <structname>v4l2_buffer</structname> structure is + specified in <xref linkend="buffer" />.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer <structfield>type</structfield> is not +supported, or the <structfield>index</structfield> is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-querycap.xml b/Documentation/DocBook/v4l/vidioc-querycap.xml new file mode 100644 index 0000000..6ab7e25 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-querycap.xml @@ -0,0 +1,284 @@ +<refentry id="vidioc-querycap"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERYCAP</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERYCAP</refname> + <refpurpose>Query device capabilities</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_capability *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERYCAP</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>All V4L2 devices support the +<constant>VIDIOC_QUERYCAP</constant> ioctl. It is used to identify +kernel devices compatible with this specification and to obtain +information about driver and hardware capabilities. The ioctl takes a +pointer to a &v4l2-capability; which is filled by the driver. When the +driver is not compatible with this specification the ioctl returns an +&EINVAL;.</para> + + <table pgwide="1" frame="none" id="v4l2-capability"> + <title>struct <structname>v4l2_capability</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u8</entry> + <entry><structfield>driver</structfield>[16]</entry> + <entry><para>Name of the driver, a unique NUL-terminated +ASCII string. For example: "bttv". Driver specific applications can +use this information to verify the driver identity. It is also useful +to work around known bugs, or to identify drivers in error reports. +The driver version is stored in the <structfield>version</structfield> +field.</para><para>Storing strings in fixed sized arrays is bad +practice but unavoidable here. Drivers and applications should take +precautions to never read or write beyond the end of the array and to +make sure the strings are properly NUL-terminated.</para></entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>card</structfield>[32]</entry> + <entry>Name of the device, a NUL-terminated ASCII string. +For example: "Yoyodyne TV/FM". One driver may support different brands +or models of video hardware. This information is intended for users, +for example in a menu of available devices. Since multiple TV cards of +the same brand may be installed which are supported by the same +driver, this name should be combined with the character device file +name (⪚ <filename>/dev/video2</filename>) or the +<structfield>bus_info</structfield> string to avoid +ambiguities.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>bus_info</structfield>[32]</entry> + <entry>Location of the device in the system, a +NUL-terminated ASCII string. For example: "PCI Slot 4". This +information is intended for users, to distinguish multiple +identical devices. If no such information is available the field may +simply count the devices controlled by the driver, or contain the +empty string (<structfield>bus_info</structfield>[0] = 0).<!-- XXX pci_dev->slot_name example --></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>version</structfield></entry> + <entry><para>Version number of the driver. Together with +the <structfield>driver</structfield> field this identifies a +particular driver. The version number is formatted using the +<constant>KERNEL_VERSION()</constant> macro:</para></entry> + </row> + <row> + <entry spanname="hspan"><para> +<programlisting> +#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c)) + +__u32 version = KERNEL_VERSION(0, 8, 1); + +printf ("Version: %u.%u.%u\n", + (version >> 16) & 0xFF, + (version >> 8) & 0xFF, + version & 0xFF); +</programlisting></para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capabilities</structfield></entry> + <entry>Device capabilities, see <xref + linkend="device-capabilities" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry>Reserved for future extensions. Drivers must set +this array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="device-capabilities"> + <title>Device Capabilities Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CAP_VIDEO_CAPTURE</constant></entry> + <entry>0x00000001</entry> + <entry>The device supports the <link +linkend="capture">Video Capture</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VIDEO_OUTPUT</constant></entry> + <entry>0x00000002</entry> + <entry>The device supports the <link +linkend="output">Video Output</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VIDEO_OVERLAY</constant></entry> + <entry>0x00000004</entry> + <entry>The device supports the <link +linkend="overlay">Video Overlay</link> interface. A video overlay device +typically stores captured images directly in the video memory of a +graphics card, with hardware clipping and scaling.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VBI_CAPTURE</constant></entry> + <entry>0x00000010</entry> + <entry>The device supports the <link linkend="raw-vbi">Raw +VBI Capture</link> interface, providing Teletext and Closed Caption +data.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VBI_OUTPUT</constant></entry> + <entry>0x00000020</entry> + <entry>The device supports the <link linkend="raw-vbi">Raw VBI Output</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_SLICED_VBI_CAPTURE</constant></entry> + <entry>0x00000040</entry> + <entry>The device supports the <link linkend="sliced">Sliced VBI Capture</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_SLICED_VBI_OUTPUT</constant></entry> + <entry>0x00000080</entry> + <entry>The device supports the <link linkend="sliced">Sliced VBI Output</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_RDS_CAPTURE</constant></entry> + <entry>0x00000100</entry> + <entry>The device supports the <link linkend="rds">RDS</link> interface.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_VIDEO_OUTPUT_OVERLAY</constant></entry> + <entry>0x00000200</entry> + <entry>The device supports the <link linkend="osd">Video +Output Overlay</link> (OSD) interface. Unlike the <wordasword>Video +Overlay</wordasword> interface, this is a secondary function of video +output devices and overlays an image onto an outgoing video signal. +When the driver sets this flag, it must clear the +<constant>V4L2_CAP_VIDEO_OVERLAY</constant> flag and vice +versa.<footnote><para>The &v4l2-framebuffer; lacks an +&v4l2-buf-type; field, therefore the type of overlay is implied by the +driver capabilities.</para></footnote></entry> + </row> + <row> + <entry><constant>V4L2_CAP_HW_FREQ_SEEK</constant></entry> + <entry>0x00000400</entry> + <entry>The device supports the &VIDIOC-S-HW-FREQ-SEEK; ioctl for +hardware frequency seeking.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_TUNER</constant></entry> + <entry>0x00010000</entry> + <entry>The device has some sort of tuner to +receive RF-modulated video signals. For more information about +tuner programming see +<xref linkend="tuner" />.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_AUDIO</constant></entry> + <entry>0x00020000</entry> + <entry>The device has audio inputs or outputs. It may or +may not support audio recording or playback, in PCM or compressed +formats. PCM audio support must be implemented as ALSA or OSS +interface. For more information on audio inputs and outputs see <xref + linkend="audio" />.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_RADIO</constant></entry> + <entry>0x00040000</entry> + <entry>This is a radio receiver.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_MODULATOR</constant></entry> + <entry>0x00080000</entry> + <entry>The device has some sort of modulator to +emit RF-modulated video/audio signals. For more information about +modulator programming see +<xref linkend="tuner" />.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_READWRITE</constant></entry> + <entry>0x01000000</entry> + <entry>The device supports the <link +linkend="rw">read()</link> and/or <link linkend="rw">write()</link> +I/O methods.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_ASYNCIO</constant></entry> + <entry>0x02000000</entry> + <entry>The device supports the <link +linkend="async">asynchronous</link> I/O methods.</entry> + </row> + <row> + <entry><constant>V4L2_CAP_STREAMING</constant></entry> + <entry>0x04000000</entry> + <entry>The device supports the <link +linkend="mmap">streaming</link> I/O method.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The device is not compatible with this +specification.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> + diff --git a/Documentation/DocBook/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/v4l/vidioc-queryctrl.xml new file mode 100644 index 0000000..4876ff1 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-queryctrl.xml @@ -0,0 +1,428 @@ +<refentry id="vidioc-queryctrl"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERYCTRL, VIDIOC_QUERYMENU</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERYCTRL</refname> + <refname>VIDIOC_QUERYMENU</refname> + <refpurpose>Enumerate controls and menu control items</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_queryctrl *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_querymenu *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERYCTRL, VIDIOC_QUERYMENU</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a control applications set the +<structfield>id</structfield> field of a &v4l2-queryctrl; and call the +<constant>VIDIOC_QUERYCTRL</constant> ioctl with a pointer to this +structure. The driver fills the rest of the structure or returns an +&EINVAL; when the <structfield>id</structfield> is invalid.</para> + + <para>It is possible to enumerate controls by calling +<constant>VIDIOC_QUERYCTRL</constant> with successive +<structfield>id</structfield> values starting from +<constant>V4L2_CID_BASE</constant> up to and exclusive +<constant>V4L2_CID_BASE_LASTP1</constant>. Drivers may return +<errorcode>EINVAL</errorcode> if a control in this range is not +supported. Further applications can enumerate private controls, which +are not defined in this specification, by starting at +<constant>V4L2_CID_PRIVATE_BASE</constant> and incrementing +<structfield>id</structfield> until the driver returns +<errorcode>EINVAL</errorcode>.</para> + + <para>In both cases, when the driver sets the +<constant>V4L2_CTRL_FLAG_DISABLED</constant> flag in the +<structfield>flags</structfield> field this control is permanently +disabled and should be ignored by the application.<footnote> + <para><constant>V4L2_CTRL_FLAG_DISABLED</constant> was +intended for two purposes: Drivers can skip predefined controls not +supported by the hardware (although returning EINVAL would do as +well), or disable predefined and private controls after hardware +detection without the trouble of reordering control arrays and indices +(EINVAL cannot be used to skip private controls because it would +prematurely end the enumeration).</para></footnote></para> + + <para>When the application ORs <structfield>id</structfield> with +<constant>V4L2_CTRL_FLAG_NEXT_CTRL</constant> the driver returns the +next supported control, or <errorcode>EINVAL</errorcode> if there is +none. Drivers which do not support this flag yet always return +<errorcode>EINVAL</errorcode>.</para> + + <para>Additional information is required for menu controls: the +names of the menu items. To query them applications set the +<structfield>id</structfield> and <structfield>index</structfield> +fields of &v4l2-querymenu; and call the +<constant>VIDIOC_QUERYMENU</constant> ioctl with a pointer to this +structure. The driver fills the rest of the structure or returns an +&EINVAL; when the <structfield>id</structfield> or +<structfield>index</structfield> is invalid. Menu items are enumerated +by calling <constant>VIDIOC_QUERYMENU</constant> with successive +<structfield>index</structfield> values from &v4l2-queryctrl; +<structfield>minimum</structfield> (0) to +<structfield>maximum</structfield>, inclusive.</para> + + <para>See also the examples in <xref linkend="control" />.</para> + + <table pgwide="1" frame="none" id="v4l2-queryctrl"> + <title>struct <structname>v4l2_queryctrl</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>Identifies the control, set by the application. See +<xref linkend="control-id" /> for predefined IDs. When the ID is ORed +with V4L2_CTRL_FLAG_NEXT_CTRL the driver clears the flag and returns +the first control with a higher ID. Drivers which do not support this +flag yet always return an &EINVAL;.</entry> + </row> + <row> + <entry>&v4l2-ctrl-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of control, see <xref + linkend="v4l2-ctrl-type" />.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the control, a NUL-terminated ASCII +string. This information is intended for the user.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>minimum</structfield></entry> + <entry>Minimum value, inclusive. This field gives a lower +bound for <constant>V4L2_CTRL_TYPE_INTEGER</constant> controls and the +lowest valid index (always 0) for <constant>V4L2_CTRL_TYPE_MENU</constant> controls. +For <constant>V4L2_CTRL_TYPE_STRING</constant> controls the minimum value +gives the minimum length of the string. This length <emphasis>does not include the terminating +zero</emphasis>. It may not be valid for any other type of control, including +<constant>V4L2_CTRL_TYPE_INTEGER64</constant> controls. Note that this is a +signed value.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>maximum</structfield></entry> + <entry>Maximum value, inclusive. This field gives an upper +bound for <constant>V4L2_CTRL_TYPE_INTEGER</constant> controls and the +highest valid index for <constant>V4L2_CTRL_TYPE_MENU</constant> +controls. +For <constant>V4L2_CTRL_TYPE_STRING</constant> controls the maximum value +gives the maximum length of the string. This length <emphasis>does not include the terminating +zero</emphasis>. It may not be valid for any other type of control, including +<constant>V4L2_CTRL_TYPE_INTEGER64</constant> controls. Note that this is a +signed value.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>step</structfield></entry> + <entry><para>This field gives a step size for +<constant>V4L2_CTRL_TYPE_INTEGER</constant> controls. For +<constant>V4L2_CTRL_TYPE_STRING</constant> controls this field refers to +the string length that has to be a multiple of this step size. +It may not be valid for any other type of control, including +<constant>V4L2_CTRL_TYPE_INTEGER64</constant> +controls.</para><para>Generally drivers should not scale hardware +control values. It may be necessary for example when the +<structfield>name</structfield> or <structfield>id</structfield> imply +a particular unit and the hardware actually accepts only multiples of +said unit. If so, drivers must take care values are properly rounded +when scaling, such that errors will not accumulate on repeated +read-write cycles.</para><para>This field gives the smallest change of +an integer control actually affecting hardware. Often the information +is needed when the user can change controls by keyboard or GUI +buttons, rather than a slider. When for example a hardware register +accepts values 0-511 and the driver reports 0-65535, step should be +128.</para><para>Note that although signed, the step value is supposed to +be always positive.</para></entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>default_value</structfield></entry> + <entry>The default value of a +<constant>V4L2_CTRL_TYPE_INTEGER</constant>, +<constant>_BOOLEAN</constant> or <constant>_MENU</constant> control. +Not valid for other types of controls. Drivers reset controls only +when the driver is loaded, not later, in particular not when the +func-open; is called.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Control flags, see <xref + linkend="control-flags" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-querymenu"> + <title>struct <structname>v4l2_querymenu</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry>Identifies the control, set by the application +from the respective &v4l2-queryctrl; +<structfield>id</structfield>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Index of the menu item, starting at zero, set by + the application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the menu item, a NUL-terminated ASCII +string. This information is intended for the user.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield></entry> + <entry>Reserved for future extensions. Drivers must set +the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-ctrl-type"> + <title>enum v4l2_ctrl_type</title> + <tgroup cols="5" align="left"> + <colspec colwidth="30*" /> + <colspec colwidth="5*" align="center" /> + <colspec colwidth="5*" align="center" /> + <colspec colwidth="5*" align="center" /> + <colspec colwidth="55*" /> + <thead> + <row> + <entry>Type</entry> + <entry><structfield>minimum</structfield></entry> + <entry><structfield>step</structfield></entry> + <entry><structfield>maximum</structfield></entry> + <entry>Description</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_CTRL_TYPE_INTEGER</constant></entry> + <entry>any</entry> + <entry>any</entry> + <entry>any</entry> + <entry>An integer-valued control ranging from minimum to +maximum inclusive. The step value indicates the increment between +values which are actually different on the hardware.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_BOOLEAN</constant></entry> + <entry>0</entry> + <entry>1</entry> + <entry>1</entry> + <entry>A boolean-valued control. Zero corresponds to +"disabled", and one means "enabled".</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_MENU</constant></entry> + <entry>0</entry> + <entry>1</entry> + <entry>N-1</entry> + <entry>The control has a menu of N choices. The names of +the menu items can be enumerated with the +<constant>VIDIOC_QUERYMENU</constant> ioctl.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_BUTTON</constant></entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>A control which performs an action when set. +Drivers must ignore the value passed with +<constant>VIDIOC_S_CTRL</constant> and return an &EINVAL; on a +<constant>VIDIOC_G_CTRL</constant> attempt.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_INTEGER64</constant></entry> + <entry>n/a</entry> + <entry>n/a</entry> + <entry>n/a</entry> + <entry>A 64-bit integer valued control. Minimum, maximum +and step size cannot be queried.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_STRING</constant></entry> + <entry>≥ 0</entry> + <entry>≥ 1</entry> + <entry>≥ 0</entry> + <entry>The minimum and maximum string lengths. The step size +means that the string must be (minimum + N * step) characters long for +N ≥ 0. These lengths do not include the terminating zero, so in order to +pass a string of length 8 to &VIDIOC-S-EXT-CTRLS; you need to set the +<structfield>size</structfield> field of &v4l2-ext-control; to 9. For &VIDIOC-G-EXT-CTRLS; you can +set the <structfield>size</structfield> field to <structfield>maximum</structfield> + 1. +Which character encoding is used will depend on the string control itself and +should be part of the control documentation.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant></entry> + <entry>n/a</entry> + <entry>n/a</entry> + <entry>n/a</entry> + <entry>This is not a control. When +<constant>VIDIOC_QUERYCTRL</constant> is called with a control ID +equal to a control class code (see <xref linkend="ctrl-class" />), the +ioctl returns the name of the control class and this control type. +Older drivers which do not support this feature return an +&EINVAL;.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="control-flags"> + <title>Control Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CTRL_FLAG_DISABLED</constant></entry> + <entry>0x0001</entry> + <entry>This control is permanently disabled and should be +ignored by the application. Any attempt to change the control will +result in an &EINVAL;.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_GRABBED</constant></entry> + <entry>0x0002</entry> + <entry>This control is temporarily unchangeable, for +example because another application took over control of the +respective resource. Such controls may be displayed specially in a +user interface. Attempts to change the control may result in an +&EBUSY;.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_READ_ONLY</constant></entry> + <entry>0x0004</entry> + <entry>This control is permanently readable only. Any +attempt to change the control will result in an &EINVAL;.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_UPDATE</constant></entry> + <entry>0x0008</entry> + <entry>A hint that changing this control may affect the +value of other controls within the same control class. Applications +should update their user interface accordingly.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_INACTIVE</constant></entry> + <entry>0x0010</entry> + <entry>This control is not applicable to the current +configuration and should be displayed accordingly in a user interface. +For example the flag may be set on a MPEG audio level 2 bitrate +control when MPEG audio encoding level 1 was selected with another +control.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_SLIDER</constant></entry> + <entry>0x0020</entry> + <entry>A hint that this control is best represented as a +slider-like element in a user interface.</entry> + </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_WRITE_ONLY</constant></entry> + <entry>0x0040</entry> + <entry>This control is permanently writable only. Any +attempt to read the control will result in an &EACCES; error code. This +flag is typically present for relative controls or action controls where +writing a value will cause the device to carry out a given action +(⪚ motor control) but no meaningful value can be returned.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-queryctrl; <structfield>id</structfield> +is invalid. The &v4l2-querymenu; <structfield>id</structfield> or +<structfield>index</structfield> is invalid.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para>An attempt was made to read a write-only control.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-querystd.xml b/Documentation/DocBook/v4l/vidioc-querystd.xml new file mode 100644 index 0000000..b5a7ff9 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-querystd.xml @@ -0,0 +1,83 @@ +<refentry id="vidioc-querystd"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERYSTD</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERYSTD</refname> + <refpurpose>Sense the video standard received by the current +input</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>v4l2_std_id *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_QUERYSTD</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The hardware may be able to detect the current video +standard automatically. To do so, applications call <constant> +VIDIOC_QUERYSTD</constant> with a pointer to a &v4l2-std-id; type. The +driver stores here a set of candidates, this can be a single flag or a +set of supported standards if for example the hardware can only +distinguish between 50 and 60 Hz systems. When detection is not +possible or fails, the set must contain all standards supported by the +current video input or output.</para> + + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>This ioctl is not supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/v4l/vidioc-reqbufs.xml new file mode 100644 index 0000000..bab3808 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-reqbufs.xml @@ -0,0 +1,160 @@ +<refentry id="vidioc-reqbufs"> + <refmeta> + <refentrytitle>ioctl VIDIOC_REQBUFS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_REQBUFS</refname> + <refpurpose>Initiate Memory Mapping or User Pointer I/O</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_requestbuffers *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_REQBUFS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>This ioctl is used to initiate <link linkend="mmap">memory +mapped</link> or <link linkend="userp">user pointer</link> +I/O. Memory mapped buffers are located in device memory and must be +allocated with this ioctl before they can be mapped into the +application's address space. User buffers are allocated by +applications themselves, and this ioctl is merely used to switch the +driver into user pointer I/O mode.</para> + + <para>To allocate device buffers applications initialize three +fields of a <structname>v4l2_requestbuffers</structname> structure. +They set the <structfield>type</structfield> field to the respective +stream or buffer type, the <structfield>count</structfield> field to +the desired number of buffers, and <structfield>memory</structfield> +must be set to <constant>V4L2_MEMORY_MMAP</constant>. When the ioctl +is called with a pointer to this structure the driver attempts to +allocate the requested number of buffers and stores the actual number +allocated in the <structfield>count</structfield> field. It can be +smaller than the number requested, even zero, when the driver runs out +of free memory. A larger number is possible when the driver requires +more buffers to function correctly.<footnote> + <para>For example video output requires at least two buffers, +one displayed and one filled by the application.</para> + </footnote> When memory mapping I/O is not supported the ioctl +returns an &EINVAL;.</para> + + <para>Applications can call <constant>VIDIOC_REQBUFS</constant> +again to change the number of buffers, however this cannot succeed +when any buffers are still mapped. A <structfield>count</structfield> +value of zero frees all buffers, after aborting or finishing any DMA +in progress, an implicit &VIDIOC-STREAMOFF;. <!-- mhs: I see no +reason why munmap()ping one or even all buffers must imply +streamoff.--></para> + + <para>To negotiate user pointer I/O, applications initialize only +the <structfield>type</structfield> field and set +<structfield>memory</structfield> to +<constant>V4L2_MEMORY_USERPTR</constant>. When the ioctl is called +with a pointer to this structure the driver prepares for user pointer +I/O, when this I/O method is not supported the ioctl returns an +&EINVAL;.</para> + + <table pgwide="1" frame="none" id="v4l2-requestbuffers"> + <title>struct <structname>v4l2_requestbuffers</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>count</structfield></entry> + <entry>The number of buffers requested or granted. This +field is only used when <structfield>memory</structfield> is set to +<constant>V4L2_MEMORY_MMAP</constant>.</entry> + </row> + <row> + <entry>&v4l2-buf-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>Type of the stream or buffers, this is the same +as the &v4l2-format; <structfield>type</structfield> field. See <xref + linkend="v4l2-buf-type" /> for valid values.</entry> + </row> + <row> + <entry>&v4l2-memory;</entry> + <entry><structfield>memory</structfield></entry> + <entry>Applications set this field to +<constant>V4L2_MEMORY_MMAP</constant> or +<constant>V4L2_MEMORY_USERPTR</constant>.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[2]</entry> + <entry>A place holder for future extensions and custom +(driver defined) buffer types <constant>V4L2_BUF_TYPE_PRIVATE</constant> and +higher.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The driver supports multiple opens and I/O is already +in progress, or reallocation of buffers was attempted although one or +more are still mapped.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The buffer type (<structfield>type</structfield> field) or the +requested I/O method (<structfield>memory</structfield>) is not +supported.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-s-hw-freq-seek.xml b/Documentation/DocBook/v4l/vidioc-s-hw-freq-seek.xml new file mode 100644 index 0000000..14b3ec7 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-s-hw-freq-seek.xml @@ -0,0 +1,129 @@ +<refentry id="vidioc-s-hw-freq-seek"> + <refmeta> + <refentrytitle>ioctl VIDIOC_S_HW_FREQ_SEEK</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_S_HW_FREQ_SEEK</refname> + <refpurpose>Perform a hardware frequency seek</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_hw_freq_seek +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_S_HW_FREQ_SEEK</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Start a hardware frequency seek from the current frequency. +To do this applications initialize the <structfield>tuner</structfield>, +<structfield>type</structfield>, <structfield>seek_upward</structfield> and +<structfield>wrap_around</structfield> fields, and zero out the +<structfield>reserved</structfield> array of a &v4l2-hw-freq-seek; and +call the <constant>VIDIOC_S_HW_FREQ_SEEK</constant> ioctl with a pointer +to this structure.</para> + + <para>This ioctl is supported if the <constant>V4L2_CAP_HW_FREQ_SEEK</constant> capability is set.</para> + + <table pgwide="1" frame="none" id="v4l2-hw-freq-seek"> + <title>struct <structname>v4l2_hw_freq_seek</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>tuner</structfield></entry> + <entry>The tuner index number. This is the +same value as in the &v4l2-input; <structfield>tuner</structfield> +field and the &v4l2-tuner; <structfield>index</structfield> field.</entry> + </row> + <row> + <entry>&v4l2-tuner-type;</entry> + <entry><structfield>type</structfield></entry> + <entry>The tuner type. This is the same value as in the +&v4l2-tuner; <structfield>type</structfield> field.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>seek_upward</structfield></entry> + <entry>If non-zero, seek upward from the current frequency, else seek downward.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>wrap_around</structfield></entry> + <entry>If non-zero, wrap around when at the end of the frequency range, else stop seeking.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[8]</entry> + <entry>Reserved for future extensions. Drivers and + applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <structfield>tuner</structfield> index is out of +bounds or the value in the <structfield>type</structfield> field is +wrong.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EAGAIN</errorcode></term> + <listitem> + <para>The ioctl timed-out. Try again.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> diff --git a/Documentation/DocBook/v4l/vidioc-streamon.xml b/Documentation/DocBook/v4l/vidioc-streamon.xml new file mode 100644 index 0000000..e42bff1 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-streamon.xml @@ -0,0 +1,106 @@ +<refentry id="vidioc-streamon"> + <refmeta> + <refentrytitle>ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_STREAMON</refname> + <refname>VIDIOC_STREAMOFF</refname> + <refpurpose>Start or stop streaming I/O</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const int *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_STREAMON, VIDIOC_STREAMOFF</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>The <constant>VIDIOC_STREAMON</constant> and +<constant>VIDIOC_STREAMOFF</constant> ioctl start and stop the capture +or output process during streaming (<link linkend="mmap">memory +mapping</link> or <link linkend="userp">user pointer</link>) I/O.</para> + + <para>Specifically the capture hardware is disabled and no input +buffers are filled (if there are any empty buffers in the incoming +queue) until <constant>VIDIOC_STREAMON</constant> has been called. +Accordingly the output hardware is disabled, no video signal is +produced until <constant>VIDIOC_STREAMON</constant> has been called. +The ioctl will succeed only when at least one output buffer is in the +incoming queue.</para> + + <para>The <constant>VIDIOC_STREAMOFF</constant> ioctl, apart of +aborting or finishing any DMA in progress, unlocks any user pointer +buffers locked in physical memory, and it removes all buffers from the +incoming and outgoing queues. That means all images captured but not +dequeued yet will be lost, likewise all images enqueued for output but +not transmitted yet. I/O returns to the same state as after calling +&VIDIOC-REQBUFS; and can be restarted accordingly.</para> + + <para>Both ioctls take a pointer to an integer, the desired buffer or +stream type. This is the same as &v4l2-requestbuffers; +<structfield>type</structfield>.</para> + + <para>Note applications can be preempted for unknown periods right +before or after the <constant>VIDIOC_STREAMON</constant> or +<constant>VIDIOC_STREAMOFF</constant> calls, there is no notion of +starting or stopping "now". Buffer timestamps can be used to +synchronize with other events.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>Streaming I/O is not supported, the buffer +<structfield>type</structfield> is not supported, or no buffers have +been allocated (memory mapping) or enqueued (output) yet.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> |
