[FFmpeg-devel] [PATCH] avformat/movenc: fixed fmp4 packets containing incorrect flags after transcoding

[Steven Liu]

<1035567130 at qq.com> 于2023年4月10日周一 20:43写道：
>
> From: Wang Yaqiang <wangyaqiang03 at kuaishou.com>
>
> When write multi-trun box, the MOV_TRUN_FIRST_SAMPLE_FLAGS flag
> need judge by first param, not 0.
> If the original video contains consecutive I frames,
> this will cause the packets of fmp4 have error sample_flags ,
> and then incorrect keyframes were generated,
> and then error packet will be seeked.
>
> Signed-off-by: Wang Yaqiang <wangyaqiang03 at kuaishou.com>
> ---
>  libavformat/movenc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index c370922c7d..946e79c5ac 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -4858,8 +4858,8 @@ static int mov_write_trun_tag(AVIOContext *pb, MOVMuxContext *mov,
>          if (i > first && get_sample_flags(track, &track->cluster[i]) != track->default_sample_flags)
>              flags |= MOV_TRUN_SAMPLE_FLAGS;
>      }
> -    if (!(flags & MOV_TRUN_SAMPLE_FLAGS) && track->entry > 0 &&
> -         get_sample_flags(track, &track->cluster[0]) != track->default_sample_flags)
> +    if (!(flags & MOV_TRUN_SAMPLE_FLAGS) && track->entry > first &&
> +         get_sample_flags(track, &track->cluster[first]) != track->default_sample_flags)
>          flags |= MOV_TRUN_FIRST_SAMPLE_FLAGS;
>      if (track->flags & MOV_TRACK_CTTS)
>          flags |= MOV_TRUN_SAMPLE_CTS;
> --
> 2.39.2
>
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Test ok here.


Thanks
Steven