Opened 8 years ago

Last modified 8 years ago

#2033 new defect

Glitchy durations on dumpfiles from some DVDs. (SVN-r34537 (Gentoo)-4.5.3)

Reported by: matt@… Owned by: reimar
Priority: normal Component: demuxer
Version: 1.0rc4 Severity: normal
Keywords: Cc: compn, cehoyos
Blocked By: Blocking:
Reproduced by developer: Analyzed by developer:


Usually, I can run mplayer <source> -dumpfile video.vob, and it works just fine.

However, some DVDs end up with a VOB file with absolutely the wrong duration (e.g. The Dark Knight shows 02:32:05 when I play the DVD but 01:35:22 when I play the resulting VOB).

If I just play this VOB file (with mplayer or with vlc), it plays all the way through, but the times are all glitchy (e.g. one second we're at 01:14:14 and the next we're at 00:00:00).

Were that the only problem, I'd be okay with it, but it also doesn't encode well. If I use mencoder to make an x264 video, it is impossible to choose a framerate and a delay that sync up properly with the audio -- I can get it synced at two different places, but it will still be out of sync everywhere else.

More confusingly, I can't seem to figure out a pattern for which DVDs cause this problem. For example, most of my Avatar (TV show) DVDs work fine, but a couple episodes (e.g. four titles on a single DVD work fine, but one title does not) also exhibit this glitch.

It doesn't seem to have anything to do with the length of titles or with CSS.

This may be a known issue, but I can't find anything about it, in part because I can't think of any good keywords to search for. If it is a known issue, I'm sorry for wasting your time; would you mind pointing me in the right direction?

Otherwise, any ideas? Thank you very much for reading!

Change History (5)

comment:1 Changed 8 years ago by matt@…

Regarding the x264 encoding, I want to clarify: whether I encode (a) directly from the DVD, (b) from a vobcopy mirror of the DVD on the hard disc, or (c) from the VOB dumpfile, the same problem persists.

comment:2 Changed 8 years ago by compn

  • Cc patriotact@… added

the problem is that some dvd change framerates in different scenes. thats why sometimes mencoder cant handle encoding it.

either read up how to do it with mencoder (with telecine / detelecine filters, or progressive etc. like adding -mc 0 -noskip -vf harddup ) or use a different tool like ffmpeg.

well, you can always ask on mencoder-users mailing list...

comment:3 Changed 8 years ago by compn

oops, didnt read your whole post before i made my reply. sorry for the snark. its hard to find help if you dont know the terminology.

theres some examples to fix your problem on mencoder-users list like:
"-vf ivtc=1,pp=lb,softskip"

see if your mencoder spits out the following line:
demux_mpg: 24000/1001fps progressive NTSC content detected, switching framerate.

thats probably what causes the problem. its an old known problem, theres some ways to fix it, but probably some dvds are too tricky.

then there are complicated fixes like using avisynth. and even more complex forums like doom9 to talk about video encoding.

or there are simple tools for windows that automate the process like autogk

good luck!

comment:4 Changed 8 years ago by cehoyos

  • Cc cehoyos@… added

(Disclaimer: I live in PAL-country so the following is hear-say.)

I believe pullup is the most advanced telecine-filter and should be tried first, I can't believe there is a reason to use lb in this case (softskip is necessary iirc).

comment:5 Changed 8 years ago by compn

to answer your original bugreport title about mpeg timestamps being incorrect, this is a known bug.

its so old, its bug #4 in our bugzilla:

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