media: uapi: h264: Clean slice invariants syntax elements

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>

1 files changed, 3 insertions, 5 deletions

diff --git a/drivers/media/v4l2-core/v4l2-h264.c b/drivers/media/v4l2-core/v4l2-h264.c
index f4742408436b..5633a242520a 100644
--- a/drivers/media/v4l2-core/v4l2-h264.c
+++ b/drivers/media/v4l2-core/v4l2-h264.c
@@ -18,14 +18,12 @@
  *
  * @b: the builder context to initialize
  * @dec_params: decode parameters control
- * @slice_params: first slice parameters control
  * @sps: SPS control
  * @dpb: DPB to use when creating the reference list
  */
 void
 v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
 		const struct v4l2_ctrl_h264_decode_params *dec_params,
-		const struct v4l2_ctrl_h264_slice_params *slice_params,
 		const struct v4l2_ctrl_h264_sps *sps,
 		const struct v4l2_h264_dpb_entry dpb[V4L2_H264_NUM_DPB_ENTRIES])
 {
@@ -33,13 +31,13 @@ v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
 	unsigned int i;
 
 	max_frame_num = 1 << (sps->log2_max_frame_num_minus4 + 4);
-	cur_frame_num = slice_params->frame_num;
+	cur_frame_num = dec_params->frame_num;
 
 	memset(b, 0, sizeof(*b));
-	if (!(slice_params->flags & V4L2_H264_SLICE_FLAG_FIELD_PIC))
+	if (!(dec_params->flags & V4L2_H264_DECODE_PARAM_FLAG_FIELD_PIC))
 		b->cur_pic_order_count = min(dec_params->bottom_field_order_cnt,
 					     dec_params->top_field_order_cnt);
-	else if (slice_params->flags & V4L2_H264_SLICE_FLAG_BOTTOM_FIELD)
+	else if (dec_params->flags & V4L2_H264_DECODE_PARAM_FLAG_BOTTOM_FIELD)
 		b->cur_pic_order_count = dec_params->bottom_field_order_cnt;
 	else
 		b->cur_pic_order_count = dec_params->top_field_order_cnt;