From 8255b4d21967e978f96a87cf032471f527149794 Mon Sep 17 00:00:00 2001 From: Philipp Zabel Date: Tue, 10 Sep 2019 07:20:30 -0300 Subject: [PATCH] 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 Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/media/uapi/v4l/pixfmt-compressed.rst | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst index 292fdc116c777..55d8d690f22fa 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 -- 2.30.2