iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

media: pixfmt-compressed.rst: improve H264/HEVC/MPEG1+2/VP8+9 documentation

Browse Source 
The existing documentation was incorrect and did not correspond
to how actual codec drivers implemented this.

Update the documentation to explicitly specify what is actually
expected.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Hans Verkuil 2019-08-15 11:44:52 -03:00 committed by Mauro Carvalho Chehab
parent 051f8d2d86
commit d4e0f82ac8
1 changed files with 30 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
Documentation/media/uapi/v4l/pixfmt-compressed.rst
View File

@ -41,7 +41,12 @@ Compressed Formats
- ``V4L2_PIX_FMT_H264`` - ``V4L2_PIX_FMT_H264``
- 'H264' - 'H264'
- H264 video elementary stream with start codes. - H264 Access Unit.
The decoder expects one Access Unit per buffer.
The encoder generates one Access Unit per buffer.
If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM``
then the decoder has no requirements since it can parse all the
information from the raw bytestream.
* .. _V4L2-PIX-FMT-H264-NO-SC: * .. _V4L2-PIX-FMT-H264-NO-SC:
- ``V4L2_PIX_FMT_H264_NO_SC`` - ``V4L2_PIX_FMT_H264_NO_SC``
@ -89,12 +94,20 @@ Compressed Formats
- ``V4L2_PIX_FMT_MPEG1`` - ``V4L2_PIX_FMT_MPEG1``
- 'MPG1' - 'MPG1'
- MPEG1 video elementary stream. - MPEG1 Picture. Each buffer starts with a Picture header, followed
by other headers as needed and ending with the Picture data.
If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM``
then the decoder has no requirements since it can parse all the
information from the raw bytestream.
* .. _V4L2-PIX-FMT-MPEG2: * .. _V4L2-PIX-FMT-MPEG2:
- ``V4L2_PIX_FMT_MPEG2`` - ``V4L2_PIX_FMT_MPEG2``
- 'MPG2' - 'MPG2'
- MPEG2 video elementary stream. - MPEG2 Picture. Each buffer starts with a Picture header, followed
by other headers as needed and ending with the Picture data.
If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM``
then the decoder has no requirements since it can parse all the
information from the raw bytestream.
* .. _V4L2-PIX-FMT-MPEG2-SLICE: * .. _V4L2-PIX-FMT-MPEG2-SLICE:
- ``V4L2_PIX_FMT_MPEG2_SLICE`` - ``V4L2_PIX_FMT_MPEG2_SLICE``
@ -135,7 +148,9 @@ Compressed Formats
- ``V4L2_PIX_FMT_VP8`` - ``V4L2_PIX_FMT_VP8``
- 'VP80' - 'VP80'
- VP8 video elementary stream. - VP8 compressed video frame. The encoder generates one
compressed frame per buffer, and the decoder requires one
compressed frame per buffer.
* .. _V4L2-PIX-FMT-VP8-FRAME: * .. _V4L2-PIX-FMT-VP8-FRAME:
- ``V4L2_PIX_FMT_VP8_FRAME`` - ``V4L2_PIX_FMT_VP8_FRAME``
@ -160,12 +175,19 @@ Compressed Formats
- ``V4L2_PIX_FMT_VP9`` - ``V4L2_PIX_FMT_VP9``
- 'VP90' - 'VP90'
- VP9 video elementary stream. - VP9 compressed video frame. The encoder generates one
compressed frame per buffer, and the decoder requires one
compressed frame per buffer.
* .. _V4L2-PIX-FMT-HEVC: * .. _V4L2-PIX-FMT-HEVC:
- ``V4L2_PIX_FMT_HEVC`` - ``V4L2_PIX_FMT_HEVC``
- 'HEVC' - 'HEVC'
- HEVC/H.265 video elementary stream. - HEVC/H.265 Access Unit.
The decoder expects one Access Unit per buffer.
The encoder generates one Access Unit per buffer.
If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM``
then the decoder has no requirements since it can parse all the
information from the raw bytestream.
* .. _V4L2-PIX-FMT-FWHT: * .. _V4L2-PIX-FMT-FWHT:
- ``V4L2_PIX_FMT_FWHT`` - ``V4L2_PIX_FMT_FWHT``
@ -173,6 +195,8 @@ Compressed Formats
- Video elementary stream using a codec based on the Fast Walsh Hadamard - Video elementary stream using a codec based on the Fast Walsh Hadamard
Transform. This codec is implemented by the vicodec ('Virtual Codec') Transform. This codec is implemented by the vicodec ('Virtual Codec')
driver. See the codec-fwht.h header for more details. driver. See the codec-fwht.h header for more details.
:ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM``
since the decoder can parse all the information from the raw bytestream.
* .. _V4L2-PIX-FMT-FWHT-STATELESS: * .. _V4L2-PIX-FMT-FWHT-STATELESS:
- ``V4L2_PIX_FMT_FWHT_STATELESS`` - ``V4L2_PIX_FMT_FWHT_STATELESS``