[MEncoder-users] a-v synchronization problems of some NTSC DVDs with -oac copy

David Soukal dsoukal1 at binghamton.edu
Thu Apr 28 16:48:22 CEST 2005


I have prepared a small fragment of one of the problematic movies. I
apologize for its size (320 MB) but I wasn't able to narrow the problem
more down. The audio is almost in sync but in the very last scene, you
can see a slight delay. It seems to me that some parts are almost ok but
others are not.

I also uploaded the script that I used to convert the movie, so
hopefully you'll be able to reproduce it exactly. Just to make sure that
you can see the delay I see I added also the encoded video.

If had time, could you, please, try to reproduce the problem? I have
read the comments that it's probably XVid's (version 1.0.3) fault, but
I'd like to be sure.

Thank you very much!

In order to download the files, please use FTP to log to
with user name 'mencoder' and the password 'mplayer'. The files are in
directory /public/mencoder.

Thanks again.


Corey Hickey wrote:
> David Soukal wrote:
>>If there's anything I could do to help localize the problem, let me know.
> It would be nice if you could post a section of the movie on some public
> server so we could try it out.
> 1. Pick a DVD that gives you desync problems early on.
> 2. Run 'mplayer dvd://1 -dumpstream'. You can ctrl-c mplayer once it's
> dumped a little past where you start getting problems
> 3. Use the dd command to refine it further, like this:
> $ dd if=stream.dump of=firstpart.dump bs=1M count=100
> Adjust the count value to as small as you can while still including the
> problematic part.
> 4. Encode firstpart.vob to make sure you still have trouble.
> 5. At this point firstpart.vob will still be pretty big. See if you can
> remove some of the beginning, like this:
> $ dd if=firstpart.dump of=small.dump bs=1M skip=50
> 6. Use trial and error to find the biggest skip value you can where you
> still have trouble with small.dump.
> 7. Put the file on some http/ftp server and report the URL to us.
> -Corey
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