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* [PATCH] media: uapi: h264: clarify V4L2_PIX_FMT_H264_SLICE format
@ 2019-09-10 10:20 Philipp Zabel
  0 siblings, 0 replies; only message in thread
From: Philipp Zabel @ 2019-09-10 10:20 UTC (permalink / raw)
  To: linux-media
  Cc: Hans Verkuil, Tomasz Figa, Paul Kocialkowski, Ezequiel Garcia,
	Boris Brezillon, kernel

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>
---
 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
-- 
2.20.1


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2019-09-10 10:20 [PATCH] media: uapi: h264: clarify V4L2_PIX_FMT_H264_SLICE format Philipp Zabel

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