Commit 804e192a authored by Nicolas Dufresne's avatar Nicolas Dufresne Committed by Mauro Carvalho Chehab
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media: doc: Document dual use of H.264 pic_num/frame_num 



These two fields need documentation as they have dual meaning. It is also
confusing since pic_num is a derived value from frame_num, so this should
help application developers. If we ever need to make a V2 of this API, I
would suggest to remove pic_num entirely.

Signed-off-by: default avatarNicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: default avatarSebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@kernel.org>
parent 397edc70

Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst

+8 −2
Original line number Diff line number Diff line
@@ -649,10 +649,16 @@ Stateless Codec Control ID 
        :c:type:`timeval` in struct :c:type:`v4l2_buffer` to a __u64.

    * - __u32

      - ``pic_num``

      -

      - For short term references, this must match the derived value PicNum

	(8-28) and for long term references it must match the derived value

	LongTermPicNum (8-29). When decoding frames (as opposed to fields)

	pic_num is the same as FrameNumWrap.

    * - __u16

      - ``frame_num``

      -

      - For short term references, this must match the frame_num value from

	the slice header syntax (the driver will wrap the value if needed). For

	long term references, this must be set to the value of

	long_term_frame_idx described in the dec_ref_pic_marking() syntax.

    * - __u8

      - ``fields``

      - Specifies how the DPB entry is referenced. See :ref:`Reference Fields <h264_ref_fields>`