On Wed, 2 Mar 2016 15:29:21 -0800 Sergey Volk <serv...@chromium.org> wrote:
> As far as I can see FFmpeg currently doesn't set AVStream::id for > matroska/webm streams. I think we could use either MatroskaTrack::num > (TrackNumber) or MatroskaTrack::uid (TrackUID) for that. > I have found a few discussions claiming that TrackUID could be missing, > even though TrackUID is marked as mandatory field in matroska spec, for > example see > https://github.com/mbunkus/mkvtoolnix/issues/1050 > https://lists.w3.org/Archives/Public/public-inbandtracks/2014May/0003.html > So I guess it's safer to use TrackNumber for now. > --- > libavformat/matroskadec.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c > index d20568c..8b80df1 100644 > --- a/libavformat/matroskadec.c > +++ b/libavformat/matroskadec.c > @@ -1856,6 +1856,8 @@ static int matroska_parse_tracks(AVFormatContext *s) > return AVERROR(ENOMEM); > } > > + st->id = (int) track->num; > + > if (key_id_base64) { > /* export encryption key id as base64 metadata tag */ > av_dict_set(&st->metadata, "enc_key_id", key_id_base64, 0); The int cast makes me suspicious. It might be ok to discard the additional bits for pathological files, but I don't quite remember whether or not this can trigger UB. Might be better after all not to set the id if it's out of range? _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
