The H.264 specification requires in section 7.4.3 "Slice header semantics",
that the following values shall be the same in all slice headers:
pic_parameter_set_id
frame_num
field_pic_flag
bottom_field_flag
idr_pic_id
pic_order_cnt_lsb
delta_pic_order_cnt_bottom
delta_pic_order_cnt[ 0 ]
delta_pic_order_cnt[ 1 ]
sp_for_switch_flag
slice_group_change_cycle
These bitstream fields are part of the slice header, and therefore
passed redundantly on each slice. The purpose of the redundancy
is to make the codec fault-tolerant in network scenarios.
This is of course not needed to be reflected in the V4L2 controls,
given the bitstream has already been parsed by applications.
Therefore, move the redundant fields to the per-frame decode
parameters control (DECODE_PARAMS).
Field 'pic_parameter_set_id' is simply removed in this case,
because the PPS control must currently contain the active PPS.
Syntax elements dec_ref_pic_marking() and those related
to pic order count, remain invariant as well, and therefore,
the fields dec_ref_pic_marking_bit_size and pic_order_cnt_bit_size
are also common to all slices.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Tested-by: Jonas Karlman <jonas@kwiboo.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
DPB entry PicNum maximum value is 2*MaxFrameNum for interlaced
content (field_pic_flag=1).
As specified, MaxFrameNum is 2^(log2_max_frame_num_minus4 + 4)
and log2_max_frame_num_minus4 is in the range of 0 to 12,
which means pic_num should be a 32-bit field.
The v4l2_h264_dpb_entry struct needs to be padded to avoid a hole,
which might be also useful to allow future uAPI extensions.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Tested-by: Jonas Karlman <jonas@kwiboo.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Building those list is a standard procedure described in section
'8.2.4 Decoding process for reference picture lists construction' of
the H264 specification.
We already have 2 drivers needing the same logic (hantro and rkvdec) and
I suspect we will soon have more.
Let's provide generic helpers to create those lists.
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
