[PATCH v1 07/24] media: h264: Sort p/b reflist using frame_num

Nicolas Dufresne
2022-03-28T20:00:11Z

In the reference list builder, frame_num referers to FrameNumWrap
in the spec, which is the same as the pic_num for frame decoding.
The same applied for long_tern_pic_num and long_ter_frame_idx.

Sort all type of references by frame_num so the sort can be reused
for field reflist were the sorting is done using frame_num instead.
In short, pic_num is never actually used for building reference
lists.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
---
drivers/media/v4l2-core/v4l2-h264.c | 22 ++++++++++++----------
include/media/v4l2-h264.h | 2 --
2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-h264.c b/drivers/media/v4l2-core/v4l2-h264.c
index c9e18fd51d78..c3fad382882d 100644
--- a/drivers/media/v4l2-core/v4l2-h264.c
+++ b/drivers/media/v4l2-core/v4l2-h264.c
@@ -50,7 +50,6 @@ v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
if (!(dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
continue;

- b->refs[i].pic_num = dpb[i].pic_num;
if (dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM)
b->refs[i].longterm = true;

@@ -139,15 +138,18 @@ static int v4l2_h264_p_ref_list_cmp(const void *ptra, const void *ptrb,
}

/*
- * Short term pics in descending pic num order, long term ones in
- * ascending order.
+ * For frames, short term pics are in descending pic num order and long
+ * term ones in ascending order. For field this is the same direction
+ * but with frame_num (wrapped). As for frame the pic_num and frame_num
+ * are the same (see formula (8-28) and (8-29)) use the frame_num and share
+ * this funciton between frame and field reflist.
*/
if (!builder->refs[idxa].longterm)
return builder->refs[idxb].frame_num <
builder->refs[idxa].frame_num ?
-1 : 1;

- return builder->refs[idxa].pic_num < builder->refs[idxb].pic_num ?
+ return builder->refs[idxa].frame_num < builder->refs[idxb].frame_num ?
-1 : 1;
}

@@ -173,10 +175,10 @@ static int v4l2_h264_b0_ref_list_cmp(const void *ptra, const void *ptrb,
return 1;
}

- /* Long term pics in ascending pic num order. */
+ /* Long term pics in ascending frame num order. */
if (builder->refs[idxa].longterm)
- return builder->refs[idxa].pic_num <
- builder->refs[idxb].pic_num ?
+ return builder->refs[idxa].frame_num <
+ builder->refs[idxb].frame_num ?
-1 : 1;

poca = v4l2_h264_get_poc(builder, ptra);
@@ -218,10 +220,10 @@ static int v4l2_h264_b1_ref_list_cmp(const void *ptra, const void *ptrb,
return 1;
}

- /* Long term pics in ascending pic num order. */
+ /* Long term pics in ascending frame num order. */
if (builder->refs[idxa].longterm)
- return builder->refs[idxa].pic_num <
- builder->refs[idxb].pic_num ?
+ return builder->refs[idxa].frame_num <
+ builder->refs[idxb].frame_num ?
-1 : 1;

poca = v4l2_h264_get_poc(builder, ptra);
diff --git a/include/media/v4l2-h264.h b/include/media/v4l2-h264.h
index 4cef717b3f18..0d9eaa956123 100644
--- a/include/media/v4l2-h264.h
+++ b/include/media/v4l2-h264.h
@@ -18,7 +18,6 @@
* @refs.top_field_order_cnt: top field order count
* @refs.bottom_field_order_cnt: bottom field order count
* @refs.frame_num: reference frame number
- * @refs.pic_num: reference picture number
* @refs.longterm: set to true for a long term reference
* @refs: array of references
* @cur_pic_order_count: picture order count of the frame being decoded
@@ -36,7 +35,6 @@ struct v4l2_h264_reflist_builder {
s32 top_field_order_cnt;
s32 bottom_field_order_cnt;
int frame_num;
- u32 pic_num;
u16 longterm : 1;
} refs[V4L2_H264_NUM_DPB_ENTRIES];

--
2.34.1