[FFmpeg-devel] [PATCH 1/8] cbs_h266: fix inference for sh_lmcs_used_flag and sh_explicit_scaling_list_used_flag

James Almer jamrial at gmail.com
Mon Aug 7 18:17:25 EEST 2023


On 8/7/2023 11:55 AM, Nuo Mi wrote:
> if sh_picture_header_in_slice_header_flag is true
> sh_lmcs_used_flag and sh_explicit_scaling_list_used_flag are infered from ph
> ---
>   libavcodec/cbs_h266_syntax_template.c | 24 ++++++++++++++----------
>   1 file changed, 14 insertions(+), 10 deletions(-)
> 
> diff --git a/libavcodec/cbs_h266_syntax_template.c b/libavcodec/cbs_h266_syntax_template.c
> index 98a8e033bf..857882655b 100644
> --- a/libavcodec/cbs_h266_syntax_template.c
> +++ b/libavcodec/cbs_h266_syntax_template.c
> @@ -3151,17 +3151,21 @@ static int FUNC(slice_header) (CodedBitstreamContext *ctx, RWContext *rw,
>           infer(sh_alf_enabled_flag, 0);
>       }
>   
> -    if (ph->ph_lmcs_enabled_flag &&
> -        !current->sh_picture_header_in_slice_header_flag)
> -        flag(sh_lmcs_used_flag);
> -    else
> -        infer(sh_lmcs_used_flag, 0);
> +    if (current->sh_picture_header_in_slice_header_flag) {
> +        infer(sh_lmcs_used_flag, ph->ph_lmcs_enabled_flag);
> +        infer(sh_explicit_scaling_list_used_flag,
> +            ph->ph_explicit_scaling_list_enabled_flag);
> +    } else {
> +        if (ph->ph_lmcs_enabled_flag)
> +            flag(sh_lmcs_used_flag);
> +        else
> +            infer(sh_lmcs_used_flag, 0);
>   
> -    if (ph->ph_explicit_scaling_list_enabled_flag &&
> -        !current->sh_picture_header_in_slice_header_flag)
> -        flag(sh_explicit_scaling_list_used_flag);
> -    else
> -        infer(sh_explicit_scaling_list_used_flag, 0);
> +        if (ph->ph_explicit_scaling_list_enabled_flag)
> +            flag(sh_explicit_scaling_list_used_flag);
> +        else
> +            infer(sh_explicit_scaling_list_used_flag, 0);
> +    }
>   
>       if (!pps->pps_rpl_info_in_ph_flag &&
>           ((nal_unit_type != VVC_IDR_W_RADL &&

Do you know which samples from the conformance suite exercise this, and 
patches 2 and 3?


More information about the ffmpeg-devel mailing list