[FFmpeg-devel] [PATCH] avformat/av1dec: fix setting AVPacket->pos in Annex-B demuxer

[James Almer]

On 4/28/2025 7:02 PM, James Almer wrote:
> This demuxers reads encapsulation bytes before reading codec data into the
> output packets, so take such offset into consideration.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>   libavformat/av1dec.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/libavformat/av1dec.c b/libavformat/av1dec.c
> index 8c0b8fe975..38001b124f 100644
> --- a/libavformat/av1dec.c
> +++ b/libavformat/av1dec.c
> @@ -36,6 +36,7 @@ typedef struct AV1DemuxContext {
>       AVRational framerate;
>       uint32_t temporal_unit_size;
>       uint32_t frame_unit_size;
> +    int64_t pos;
>   } AV1DemuxContext;
>   
>   //return < 0 if we need more data
> @@ -96,6 +97,8 @@ static int av1_read_header(AVFormatContext *s)
>       if (ret < 0)
>           return ret;
>   
> +    c->pos = avio_tell(s->pb);
> +
>       return 0;
>   }
>   
> @@ -224,6 +227,7 @@ static int annexb_read_packet(AVFormatContext *s, AVPacket *pkt)
>   {
>       AV1DemuxContext *const c = s->priv_data;
>       uint32_t obu_unit_size;
> +    int64_t pos = c->pos;
>       int ret, len;
>   
>   retry:
> @@ -234,6 +238,7 @@ retry:
>       }
>   
>       if (!c->temporal_unit_size) {
> +        c->pos = avio_tell(s->pb);
>           len = leb(s->pb, &c->temporal_unit_size, 1);
>           if (len == AVERROR_EOF) goto end;
>           else if (len < 0) return len;
> @@ -279,6 +284,9 @@ end:
>       if (ret == AVERROR(EAGAIN))
>           goto retry;
>   
> +    if (!ret)
> +        pkt->pos = pos;
> +
>       return ret;
>   }

Will apply.

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