[FFmpeg-devel] [PATCH 3/5] avformat/mxfdec: guess wrapping of tracks by other tracks with the same body sid

[Tomas Härdin]

fre 2019-04-12 klockan 01:09 +0200 skrev Marton Balint:
> This affects the following samples:
> 
> samples/ffmpeg-bugs/roundup/issue1775/av_seek_frame_failure.mxf
> samples/ffmpeg-bugs/trac/ticket1957/16ch.mxf
> samples/ffmpeg-bugs/trac/ticket5016/r0.mxf
> samples/ffmpeg-bugs/trac/ticket5016/r1.mxf
> samples/ffmpeg-bugs/trac/ticket5316/hq.MXF
> samples/ffmpeg-bugs/trac/ticket5316/hqx.MXF
> 
> Some AVPacket->pos values are changed because for frame wrapped tracks we point
> to the KLV offset and not the data.
> 
> > Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
>  libavformat/mxfdec.c | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)
> 
> diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> index 18c038c3f6..236294880e 100644
> --- a/libavformat/mxfdec.c
> +++ b/libavformat/mxfdec.c
> @@ -2144,6 +2144,16 @@ static int mxf_add_metadata_stream(MXFContext *mxf, MXFTrack *track)
>      return 0;
>  }
>  
> +static MXFWrappingScheme mxf_get_wrapping_by_body_sid(AVFormatContext *s, int body_sid)
> +{
> +    for (int i = 0; i < s->nb_streams; i++) {
> +        MXFTrack *track = s->streams[i]->priv_data;
> +        if (track && track->body_sid == body_sid && track->wrapping != UnknownWrapped)
> +            return track->wrapping;

Maybe print a warning? Especially if, god forbid, the file mixes
ClipWrapping and FrameWrapping..

But now I see this function was merely moved further up, so that could
be a separate patch..

> @@ -2553,6 +2563,12 @@ static int mxf_parse_structural_metadata(MXFContext *mxf)
>          }
>      }
>  
> +    for (int i = 0; i < mxf->fc->nb_streams; i++) {
> +        MXFTrack *track = mxf->fc->streams[i]->priv_data;
> +        if (track && track->body_sid && track->wrapping == UnknownWrapped)
> +            track->wrapping = mxf_get_wrapping_by_body_sid(mxf->fc, track->body_sid);
> +    }

Or maybe put a warning here instead. Vendors should fix their dang MXF
muxers..

/Tomas