[FFmpeg-devel] [RFC] VOB files concatenation

[Stefano Sabatini]

Hi all,

I'm currently dealing with VOB concatenation issues, since it's new a
field for me (and it may unveil some bugs in FFmpeg) I'm posting it
here.

After some experimentation:
$ cat FILE1.VOB FILE2.VOB ... FILEN.VOB > ALL.VOB

results in a file which is playable by ffplay, with apparently perfect
A/V sync.

If I try to remux such a file I usually got serious A/V desync, like
in:
$ ffmpeg -i ALL.VOB -codec:v copy -codec:a copy -f mpeg ALL.REMUX.PS

Very old ffmpeg-user discussion (2005):
http://thread.gmane.org/gmane.comp.video.ffmpeg.user/1063/

where it is stated that physical concatenation with VOB files doesn't
work well with ffmpeg, and alternative tools are suggested (mplayer,
projectx, transcode).

If I'm not wrong a VOB file is nothing else that an MPEG-PS file with
a funny name, and is one of the few formats which supports physical
concatenation, at least according to our FAQ:
http://ffmpeg.org/faq.html#toc-How-can-I-join-video-files_003f

but the physical concatenation+remux trick which I showed above
doesn't seem to work well.

Do you have any advice? Is the mentioned trick supposed to work or
there are some special considerations which make the MPEG-PS format
unsuitable for such treatment?

BTW, is there any particular reason for which we don't have a DVD
import feature (like the "dvd//" mplayer syntax)?, which would be the
best technical means for integrating such a component into FFmpeg
(should be implemented like an input device, an input protocol, a
demuxer?).
-- 
FFmpeg = Fantastic & Friendly Mythic Pitiless Exxagerate Game