From: Philipp Zabel
Date: Tue, 10 Sep 2019 10:20:30 +0000 (-0300)
Subject: media: uapi: h264: clarify V4L2_PIX_FMT_H264_SLICE format
X-Git-Tag: v5.5-rc1~143^2^2~313
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=8255b4d21967e978f96a87cf032471f527149794;p=linux.git
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
---
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