[FFmpeg-devel] [PATCH 3/3] avformat/matroskadec: Improve forward compability

[Anton Khirnov]

Quoting Andreas Rheinhardt (2020-03-26 01:41:44)
> Matroska is built around the principle that a reader does not need to
> understand everything in a file in order to be able to make use of it;
> it just needs to ignore the data it doesn't know about.
> 
> Our demuxer typically follows this principle, but there is one important
> instance where it does not: A Block belonging to a TrackEntry with no
> associated stream is treated as invalid data (i.e. the demuxer will try
> to resync to the next level 1 element because it takes this as a sign
> that it has lost sync). Given that we do not create streams if we don't
> know or don't support the type of the TrackEntry, this impairs this
> demuxer's forward compability.
> 
> Furthermore, ignoring Blocks belonging to a TrackEntry without
> corresponding stream can (in future commits) also be used to ignore
> TrackEntries with obviously bogus entries without affecting the other
> TrackEntries (by not creating a stream for said TrackEntry).
> 
> Finally, given that matroska_find_track_by_num() already emits its own
> error message in case there is no TrackEntry with a given TrackNumber,
> the error message (with level AV_LOG_INFO) for this can be removed.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---

Looks reasonable

-- 
Anton Khirnov