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

[Sebastian Fricke <sebastian.fricke@xxxxxxxxxxxxx>]

Hey Nicolas,

On 28.03.2022 15:59, Nicolas Dufresne wrote:
> In the reference list builder, frame_num referers to FrameNumWrap

s/referers/refers/

> 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.

s/same applied/same applies/
s/long_ter_frame_idx/long_term_frame_idx/

> Sort all type of references by frame_num so the sort can be reused

s/frame_num so the sort/frame_num, so the order/

> for field reflist were the sorting is done using frame_num instead.

s/field/the field/
s/reflist were the sorting is done using frame_num instead/
  reflist, which is sorted by the frame_num instead/

> In short, pic_num is never actually used for building reference
> lists.
>
> Signed-off-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Fricke <sebastian.fricke@xxxxxxxxxxxxx>

> ---
> 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

s/For field this is the same direction/For fields the same direction is used/

> +	 * 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

s/As for frame the pic_num and frame_num are the same/
  The fields pic_num and frame_num are the same for frames/

> +	 * this funciton between frame and field reflist.

s/funciton/function/

Greetings,
Sebastian

> 	 */
> 	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