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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-27 21:58:31 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-27 21:58:31 (GMT) |
commit | ff9a082fda424257976f08fce942609f358015e0 (patch) | |
tree | 478e6b449b19baaf842369a13923499ce83ef895 /Documentation/media/uapi/v4l/pixfmt-nv12mt.rst | |
parent | 6a492b0f23d28e1f946cdf08e54617484400dafb (diff) | |
parent | 85538b1ad145c67198cb55d02de14ba269cc323d (diff) | |
download | linux-ff9a082fda424257976f08fce942609f358015e0.tar.xz |
Merge tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media documentation updates from Mauro Carvalho Chehab:
"This patch series does the conversion of all media documentation stuff
to Restrutured Text markup format and add them to the
Documentation/index.rst file.
The media documentation was grouped into 4 books:
- media uAPI
- media kAPI
- V4L driver-specific documentation
- DVB driver-specific documentation
It also contains several documentation improvements and one fixup
patch for a core issue with cropcap.
PS. After this patch series, the media DocBook is deprecated and
should be removed. I'll add such patch on a future pull request"
* tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (322 commits)
[media] cx23885-cardlist.rst: add a new card
[media] doc-rst: add some needed escape codes
[media] doc-rst: kapi: use :c:func: instead of :cpp:func
doc-rst: kernel-doc: fix a change introduced by mistake
[media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops
[media] dvb_ringbuffer.h: some documentation improvements
[media] v4l2-ctrls.h: fully document the header file
[media] doc-rst: Fix some typedef ugly warnings
[media] doc-rst: reorganize the kAPI v4l2 chapters
[media] rename v4l2-framework.rst to v4l2-intro.rst
[media] move V4L2 clocks to a separate .rst file
[media] v4l2-fh.rst: add cross references and markups
[media] v4l2-fh.rst: add fh contents from v4l2-framework.rst
[media] v4l2-fh.h: add documentation for it
[media] v4l2-event.rst: add cross-references and markups
[media] v4l2-event.h: document all functions
[media] v4l2-event.rst: add text from v4l2-framework.rst
[media] v4l2-framework.rst: remove videobuf quick chapter
[media] v4l2-dev: add cross-references and improve markup
[media] doc-rst: move v4l2-dev doc to a separate file
...
Diffstat (limited to 'Documentation/media/uapi/v4l/pixfmt-nv12mt.rst')
-rw-r--r-- | Documentation/media/uapi/v4l/pixfmt-nv12mt.rst | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/pixfmt-nv12mt.rst b/Documentation/media/uapi/v4l/pixfmt-nv12mt.rst new file mode 100644 index 0000000..6198941 --- /dev/null +++ b/Documentation/media/uapi/v4l/pixfmt-nv12mt.rst @@ -0,0 +1,62 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _V4L2-PIX-FMT-NV12MT: + +**************************** +V4L2_PIX_FMT_NV12MT ('TM12') +**************************** + +*man V4L2_PIX_FMT_NV12MT(2)* + +Formats with ½ horizontal and vertical chroma resolution. This format +has two planes - one for luminance and one for chrominance. Chroma +samples are interleaved. The difference to ``V4L2_PIX_FMT_NV12`` is the +memory layout. Pixels are grouped in macroblocks of 64x32 size. The +order of macroblocks in memory is also not standard. + + +Description +=========== + +This is the two-plane versions of the YUV 4:2:0 format where data is +grouped into 64x32 macroblocks. The three components are separated into +two sub-images or planes. The Y plane has one byte per pixel and pixels +are grouped into 64x32 macroblocks. The CbCr plane has the same width, +in bytes, as the Y plane (and the image), but is half as tall in pixels. +The chroma plane is also grouped into 64x32 macroblocks. + +Width of the buffer has to be aligned to the multiple of 128, and height +alignment is 32. Every four adjacent buffers - two horizontally and two +vertically are grouped together and are located in memory in Z or +flipped Z order. + +Layout of macroblocks in memory is presented in the following figure. + + +.. _nv12mt: + +.. figure:: pixfmt-nv12mt_files/nv12mt.* + :alt: nv12mt.gif + :align: center + + V4L2_PIX_FMT_NV12MT macroblock Z shape memory layout + +The requirement that width is multiple of 128 is implemented because, +the Z shape cannot be cut in half horizontally. In case the vertical +resolution of macroblocks is odd then the last row of macroblocks is +arranged in a linear order. + +In case of chroma the layout is identical. Cb and Cr samples are +interleaved. Height of the buffer is aligned to 32. + + +.. _nv12mt_ex: + +.. figure:: pixfmt-nv12mt_files/nv12mt_example.* + :alt: nv12mt_example.gif + :align: center + + Example V4L2_PIX_FMT_NV12MT memory layout of macroblocks + +Memory layout of macroblocks of ``V4L2_PIX_FMT_NV12MT`` format in most +extreme case. |