[FFmpeg-devel] [RFC]Add int64_t probesize2 to AVFormatContext

Nicolas George george at nsup.org
Mon Jul 28 10:48:08 CEST 2014

Le decadi 10 thermidor, an CCXXII, Oliver Fromme a écrit :
> There's another problem:  The palette of the subtitle streams
> is contained in the IFO files, too.  So, in order to get the
> palette right, my script uses "mencoder -vobsubout", then
> greps the palette from the resulting .idx file and feeds it
> to ffmpeg's -palette option.
> However, since I'm quite familiar with the DVD format, I have
> recently written my own little tool that is able to extract
> the palette from IFO files or DVD images, so I don't need
> mencoder anymore and all of its dependencies.  I also plan
> to extend it to be able to dump the MPEG-PS, so mplayer isn't
> needed anymore either.
> The only problem left is that subtitle streams sometimes
> begin beyond the 2 GB boundary, which Carl Eugen's patch will
> hopefully fix.
> An alternative (and even better) solution would be if I could
> tell ffmpeg that I *know* there *is* a VOBSUB subtitle stream,
> and that there's no need to try to probe for it first.  That
> would get rid of the huge delay that the probing incurs when
> scanning several GB (which is a real PITA).  Maybe I'll try to
> make a patch that can do this, like "-assume_vobsub 21" for
> subtitle stream #21, or similar.

Maybe you could have a look at tools/dvd2concat: it may help solve some of
your problems (a simple concat script concatenating a single file can be
used to declare all the streams of a headerless format) and since you are
familiar with the DVD structure, you may be able to help enhance it. If the
Perl script could parse the IFO structure without relying on a patched
lsdvd, that would be a great plus. Something could also be devised to allow
including extradata, that would fix the palette problem.


  Nicolas George

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