[FFmpeg-user] ffmpeg convert to wrong duration using dvd2concat

Nicolas George george at nsup.org
Thu Jan 21 11:36:29 CET 2016

Le primidi 1er pluviôse, an CCXXIV, Etienne Desautels a écrit :
> I'm analyzing/converting video from DVD .iso and I use dvd2concat for
> this. For at least 2 DVD, when using dvd2concat, ffmpeg return a video
> that is 1.5 x longer then the original. ffmpeg report the good duration in
> the stream info at the start, but the wrong duration at the end of the
> process. The problem is not present if I don't use dvd2concat (by
> specifying .iso directly as the input or by specifying .VOB of the mounted
> .iso). Also, video converted with the concat file will have the same frame
> repeated for the extra duration (almost 5 min. in the case below).

There is so much in the VOB files of a DVD image that anything can go wrong,
especially with so-called anti-piracy measures. Full-fledged players have
counter-measures, but not simple tools.

> file 'subfile,,start,0,end,312870912,,:/home/mmac/iso/mountpoint/VIDEO_TS/VTS_01_1.VOB'
> duration 00:04:57.734
> file 'subfile,,start,312870912,end,625534976,,:/home/mmac/iso/mountpoint/VIDEO_TS/VTS_01_1.VOB'
> duration 00:04:57.433

I suggest you extract the given segments of this file into temp files and
try to decode them to see if they match the declared duration.


  Nicolas George
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