[FFmpeg-devel] [PATCH 1/4] avcodec/cbs_h265: fix range of sps_max_sub_layers_minus1

[James Almer]

On 7/13/2024 11:58 AM, James Almer wrote:
> The VPS referenced by the SPS must always be present as the max value for
> sps_max_sub_layers_minus1 is vps_max_sub_layers_minus1. This replaces a buggy
> custom range check for the aforementioned field.
> Also, add the missing conformance check for sps_temporal_id_nesting_flag while
> at it.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>   libavcodec/cbs_h265_syntax_template.c | 37 +++++++++++++++------------
>   1 file changed, 20 insertions(+), 17 deletions(-)
> 
> diff --git a/libavcodec/cbs_h265_syntax_template.c b/libavcodec/cbs_h265_syntax_template.c
> index 86ca00a0c9..c6db439b3b 100644
> --- a/libavcodec/cbs_h265_syntax_template.c
> +++ b/libavcodec/cbs_h265_syntax_template.c
> @@ -788,25 +788,28 @@ static int FUNC(sps)(CodedBitstreamContext *ctx, RWContext *rw,
>   
>       ub(4, sps_video_parameter_set_id);
>       h265->active_vps = vps = h265->vps[current->sps_video_parameter_set_id];
> +    if (!vps) {
> +        av_log(ctx->log_ctx, AV_LOG_ERROR, "VPS id %d not available.\n",
> +               current->sps_video_parameter_set_id);
> +        return AVERROR_INVALIDDATA;
> +    }
>   
> -    u(3, sps_max_sub_layers_minus1, 0, HEVC_MAX_SUB_LAYERS - 1);
> +    u(3, sps_max_sub_layers_minus1, 0, vps->vps_max_sub_layers_minus1);
>       flag(sps_temporal_id_nesting_flag);
> -    if (vps) {
> -        if (vps->vps_max_sub_layers_minus1 > current->sps_max_sub_layers_minus1) {
> -            av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid stream: "
> -                   "sps_max_sub_layers_minus1 (%d) must be less than or equal to "
> -                   "vps_max_sub_layers_minus1 (%d).\n",
> -                   vps->vps_max_sub_layers_minus1,
> -                   current->sps_max_sub_layers_minus1);
> -            return AVERROR_INVALIDDATA;
> -        }
> -        if (vps->vps_temporal_id_nesting_flag &&
> -            !current->sps_temporal_id_nesting_flag) {
> -            av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid stream: "
> -                   "sps_temporal_id_nesting_flag must be 1 if "
> -                   "vps_temporal_id_nesting_flag is 1.\n");
> -            return AVERROR_INVALIDDATA;
> -        }
> +
> +    if (vps->vps_temporal_id_nesting_flag &&
> +        !current->sps_temporal_id_nesting_flag) {
> +        av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid stream: "
> +               "sps_temporal_id_nesting_flag must be 1 if "
> +               "vps_temporal_id_nesting_flag is 1.\n");
> +        return AVERROR_INVALIDDATA;
> +    }
> +    if (current->sps_max_sub_layers_minus1 == 0 &&
> +        current->sps_temporal_id_nesting_flag != 1) {
> +        av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid stream: "
> +               "sps_temporal_id_nesting_flag must be 1 if "
> +               "sps_max_sub_layers_minus1 is 0.\n");
> +        return AVERROR_INVALIDDATA;
>       }
>   
>       CHECK(FUNC(profile_tier_level)(ctx, rw, &current->profile_tier_level,

Will apply set.