diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-06-18 16:25:08 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-06-18 16:25:08 (GMT) |
commit | aad760136537fdfa10e5ac76bd3c79bde2100863 (patch) | |
tree | 816799b39ccf17d3a3ecfb47578d9bce05259f51 /Documentation/DocBook | |
parent | f93f0b9cf7c6056ebeb844ed68a8e44888fffa05 (diff) | |
parent | af44ad5edd1eb6ca92ed5be48e0004e1f04bf219 (diff) | |
download | linux-aad760136537fdfa10e5ac76bd3c79bde2100863.tar.xz |
Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media fixes from Mauro Carvalho Chehab:
"Series of fixes for 3.10. There are some usual driver fixes (mostly
on s5p/exynos playform drivers), plus some fixes at V4L2 core"
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (40 commits)
[media] soc_camera: error dev remove and v4l2 call
[media] sh_veu: fix the buffer size calculation
[media] sh_veu: keep power supply until the m2m context is released
[media] sh_veu: invoke v4l2_m2m_job_finish() even if a job has been aborted
[media] v4l2-ioctl: don't print the clips list
[media] v4l2-ctrls: V4L2_CTRL_CLASS_FM_RX controls are also valid radio controls
[media] cx88: fix NULL pointer dereference
[media] DocBook/media/v4l: update version number
[media] exynos4-is: Remove "sysreg" clock handling
[media] exynos4-is: Fix reported colorspace at FIMC-IS-ISP subdev
[media] exynos4-is: Ensure fimc-is clocks are not enabled until properly configured
[media] exynos4-is: Prevent NULL pointer dereference when firmware isn't loaded
[media] s5p-mfc: Add NULL check for allocated buffer
[media] s5p-mfc: added missing end-of-lines in debug messages
[media] s5p-mfc: v4l2 controls setup routine moved to initialization code
[media] s5p-mfc: separate encoder parameters for h264 and mpeg4
[media] s5p-mfc: Remove special clock usage in driver
[media] s5p-mfc: Remove unused s5p_mfc_get_decoded_status_v6() function
[media] v4l2: mem2mem: save irq flags correctly
[media] coda: v4l2-compliance fix: add VIDIOC_CREATE_BUFS support
...
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r-- | Documentation/DocBook/media/v4l/dev-codec.xml | 35 | ||||
-rw-r--r-- | Documentation/DocBook/media/v4l/v4l2.xml | 2 |
2 files changed, 23 insertions, 14 deletions
diff --git a/Documentation/DocBook/media/v4l/dev-codec.xml b/Documentation/DocBook/media/v4l/dev-codec.xml index dca0ecd..ff44c16 100644 --- a/Documentation/DocBook/media/v4l/dev-codec.xml +++ b/Documentation/DocBook/media/v4l/dev-codec.xml @@ -1,18 +1,27 @@ <title>Codec Interface</title> - <note> - <title>Suspended</title> + <para>A V4L2 codec can compress, decompress, transform, or otherwise +convert video data from one format into another format, in memory. Typically +such devices are memory-to-memory devices (i.e. devices with the +<constant>V4L2_CAP_VIDEO_M2M</constant> or <constant>V4L2_CAP_VIDEO_M2M_MPLANE</constant> +capability set). +</para> - <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 memory-to-memory video node acts just like a normal video node, but it +supports both output (sending frames from memory to the codec hardware) and +capture (receiving the processed frames from the codec hardware into memory) +stream I/O. An application will have to setup the stream +I/O for both sides and finally call &VIDIOC-STREAMON; for both capture and output +to start the codec.</para> - <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>Video compression codecs use the MPEG controls to setup their codec parameters +(note that the MPEG controls actually support many more codecs than just MPEG). +See <xref linkend="mpeg-controls"></xref>.</para> - <para>[to do]</para> + <para>Memory-to-memory devices can often be used as a shared resource: you can +open the video node multiple times, each application setting up their own codec properties +that are local to the file handle, and each can use it independently from the others. +The driver will arbitrate access to the codec and reprogram it whenever another file +handler gets access. This is different from the usual video node behavior where the video properties +are global to the device (i.e. changing something through one file handle is visible +through another file handle).</para> diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index bfc93cd..bfe823d 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -493,7 +493,7 @@ and discussions on the V4L mailing list.</revremark> </partinfo> <title>Video for Linux Two API Specification</title> - <subtitle>Revision 3.9</subtitle> + <subtitle>Revision 3.10</subtitle> <chapter id="common"> &sub-common; |