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| author |   Philipp Zabel <p.zabel@pengutronix.de> | 2019-09-10 07:20:30 -0300 |
|---|---|---|
| committer |   Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-10-01 17:12:00 -0300 |
| commit | 8255b4d21967e978f96a87cf032471f527149794 (patch) | |
| tree | a23a994a08a7544b42dc828e3d57fce34ce25b34 /Documentation/media | |
| parent | media: hantro: h264: Fix the frame_num wraparound case (diff) | |
| download | wireguard-linux-8255b4d21967e978f96a87cf032471f527149794.tar.xz wireguard-linux-8255b4d21967e978f96a87cf032471f527149794.zip | |
media: uapi: h264: clarify V4L2_PIX_FMT_H264_SLICE format
Document that the slice headers must be included for the benefit of
decoders that parse them (partially) in hardware, and that the start
code is optional. Add a link to the ITU-T Rec. H.264 specification
section that describes the slice format.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'Documentation/media')
| -rw-r--r-- | Documentation/media/uapi/v4l/pixfmt-compressed.rst | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst index 292fdc116c77..55d8d690f22f 100644 --- a/Documentation/media/uapi/v4l/pixfmt-compressed.rst +++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst @@ -61,10 +61,10 @@ Compressed Formats - ``V4L2_PIX_FMT_H264_SLICE`` - 'S264' - - H264 parsed slice data, without the start code and as - extracted from the H264 bitstream. This format is adapted for - stateless video decoders that implement an H264 pipeline - (using the :ref:`mem2mem` and :ref:`media-request-api`). + - H264 parsed slice data, including slice headers, either with or + without the start code, as extracted from the H264 bitstream. + This format is adapted for stateless video decoders that implement an + H264 pipeline (using the :ref:`mem2mem` and :ref:`media-request-api`). This pixelformat has two modifiers that must be set at least once through the ``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE`` and ``V4L2_CID_MPEG_VIDEO_H264_START_CODE`` controls. @@ -80,6 +80,10 @@ Compressed Formats appropriate number of macroblocks to decode a full corresponding frame to the matching capture buffer. + The syntax for this format is documented in :ref:`h264`, section + 7.3.2.8 "Slice layer without partitioning RBSP syntax" and the following + sections. + .. note:: This format is not yet part of the public kernel API and it |