[FFmpeg-devel] [PATCH] avformat/mov: correct 0 valued entries in stts

["zhilizhao(赵志立)"]

> On Dec 27, 2021, at 1:57 PM, Gyan Doshi <ffmpeg at gyani.pro> wrote:
> 
> As per ISO 14496-12, sample duration of 0 is invalid except for
> the last entry.
> 
> In addition, also catch 0 value for sample count.
> ---
> libavformat/mov.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
> 
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 2aed6e80ef..fb7406cdd6 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -2968,6 +2968,18 @@ static int mov_read_stts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
>         av_log(c->fc, AV_LOG_TRACE, "sample_count=%d, sample_duration=%d\n",
>                 sample_count, sample_duration);
> 
> +        if (!sample_count) {
> +        av_log(c->fc, AV_LOG_WARNING, "invalid sample count of 0 in stts for st %d at entry %u; changing to 1.\n",
> +               c->fc->nb_streams-1, i);

No, zero is a valid value, for example, fragmented mp4.

> +        sc->stts_data[i].count = sample_count = 1;
> +        }
> +
> +        if (!sample_duration && i != entries-1) {
> +        av_log(c->fc, AV_LOG_WARNING, "invalid sample delta of 0 in stts for st %d at entry %u; changing to 1.\n",
> +               c->fc->nb_streams-1, i);
> +        sc->stts_data[i].duration = sample_duration = 1;
> +        }
> +
>         duration+=(int64_t)sample_duration*(uint64_t)sample_count;
>         total_sample_count+=sample_count;
>     }
> -- 
> 2.33.0
> 
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