[MPlayer-dev-eng] [PATCH] Fix hang on demux of matroska files with 0byte-ints using 'mkv' demuxer

[Reimar Döffinger]

On Thu, Oct 07, 2010 at 03:13:54AM +0200, Michael Niedermayer wrote:
> On Sun, Sep 05, 2010 at 11:36:06AM +0200, Reimar Döffinger wrote:
> > On Wed, Sep 01, 2010 at 12:00:42AM +0200, Aurelien Jacobs wrote:
> > > On Sun, Aug 29, 2010 at 06:28:39PM +0200, Sebastian Hagen wrote:
> > > > Hello *,
> > > > 
> > > > Mplayer's 'mkv' matroska file demuxer has a bug preventing it from
> > > > parsing integers with a length of 0 bytes correctly, even though those
> > > > are valid according to the Matroska specs[1]. Thus, attempting to play
> > > > mkv files containing such integers without explicitly specifying
> > > > '-demuxer lavf' will result in an mplayer hang on demux.
> > > 
> > > What are you talking about exactly ?
> > > '-demuxer lavf' is the default behavior.
> > > And if you are using '-demuxer mkv', you are explicitly asking for
> > > trouble...
> > 
> > Could you please have a look that there's nothing _obvious_ wrong
> > with the patch?
> > And then let's just apply all these patches, even with lavf the default
> > it is easy enough for a malicious file to manage to end up with the mkv
> > demuxer by failing with the lavf one, and I don't think completely
> > removing the native one is an option, so we really can't just leave
> > these things.
> 
> why is completely removing the native one not an option?

Two reasons: rc4 will be used together with FFmpeg 0.6 where the demuxer
has a load of issues still, so we have to maintain it for that anyway.
Then there's the MAX_STREAMS issues that will not be fixed until the
next major bump.
There might be some minor things I forgot about (the lavf demuxer tries
to parse things properly, which tends to cause more issues whenever they
change the mkv format once again).