[FFmpeg-devel] [PATCH] lavc/vvc: Skip enhancement layer NAL units

[James Almer]

On 4/18/2024 3:59 PM, Frank Plowman wrote:
> The native VVC decoder does not yet support quality/spatial/multiview
> scalability.  Bitstreams requiring this feature could cause crashes.
> Patch fixes this by skipping NAL units which are not in the base layer,
> warning the user while doing so.
> 
> Signed-off-by: Frank Plowman <post at frankplowman.com>
> ---
>   libavcodec/vvc/dec.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/libavcodec/vvc/dec.c b/libavcodec/vvc/dec.c
> index a4fc40b40a..5249ddf989 100644
> --- a/libavcodec/vvc/dec.c
> +++ b/libavcodec/vvc/dec.c
> @@ -785,6 +785,11 @@ static int decode_nal_unit(VVCContext *s, VVCFrameContext *fc, const H2645NAL *n
>   
>       s->temporal_id = nal->temporal_id;
>   
> +    if (nal->nuh_layer_id > 0) {
> +        avpriv_report_missing_feature(fc->log_ctx, "Multilayer");

A more verbose message would be better.

> +        return AVERROR_PATCHWELCOME;
> +    }
> +
>       switch (unit->type) {
>       case VVC_VPS_NUT:
>       case VVC_SPS_NUT: