[FFmpeg-devel] [PATCH] mkv 0-byte integer parsing

[Reimar Döffinger]

On Tue, Sep 07, 2010 at 08:19:28PM +0100, M?ns Rullg?rd wrote:
> Reimar D?ffinger <Reimar.Doeffinger at gmx.de> writes:
> 
> > On Tue, Sep 07, 2010 at 08:12:49PM +0200, Sebastian Hagen wrote:
> >> On 2010-09-05 16:22, Sebastian Hagen wrote:
> >> >with a length of 0 bytes correctly, even though those are valid
> >> >according to the Matroska specs[1] and mkv files containing them can be
> >> My bad, that statement was incorrect. Such integers are valid
> >> according to the EBML specs[1], but not the matroska ones[2], since
> >> the latter gratuituously set a minimum uint size of 1 byte.
> >> Nevertheless, while such elements are technically invalid, some
> >> demuxers will happily accept them, and the robust thing to do would
> >> be for ffmpeg to do the same.
> >
> > In that case it would actually be good to warn, it is preferable
> > to warn about technically invalid files otherwise people will generate
> > them without noticing and the format will over time become more and
> > more painful to support.
> 
> This assumes people pay any heed whatsoever to warnings.  In actual
> practice they do not.  It is thus in my opinion preferable to fail
> with an error message for such files, optionally providing an
> unwieldy, hard to find setting to reluctantly accept these files
> regardless.  It is the only way to be sure.  Unless we nuke them from
> orbit.

Well, a warning at least gives those a chance that try.
Everyone else will probably test only against a single implementation
anyway.
But yes, it might make sense to error out for uncommon errors unless
-strict is set to an appropriate value.