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From: Philipp Zabel
To: linux-media@vger.kernel.org
Cc: Hans Verkuil ,
Tomasz Figa ,
Paul Kocialkowski ,
Ezequiel Garcia ,
Boris Brezillon ,
kernel@pengutronix.de
Subject: [PATCH] media: uapi: h264: clarify V4L2_PIX_FMT_H264_SLICE format
Date: Tue, 10 Sep 2019 12:20:30 +0200
Message-Id: <20190910102030.2236-1-p.zabel@pengutronix.de>
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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
---
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 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