ffmpeg ignores itsoffset parameter

Hi everyone,

I have recently started ripping all my DVDs onto my PC as a backup and for convenience. I have used "k9copy" to put the DVDs on the hard drive without encoding them again which results in no loss in quality. (Large hard drives are cheap nowadays).

I have decided that it would be good to have a MP4 copy of each film so that they are smaller to transport around on laptops and such, so I used "ffmpeg" to do a high-quality 2-pass MP4 of each DVD I have on my hard drive. (Taking around 6 hours per film).

I have now discovered that the audio and video are slightly out of sync in the MP4 videos. A bit of investigation showed that the DVDs have delayed audio/video tracks and that this causes the MP4 issues. I have now tried using "ffmpeg" to take the streams from the MP4s and put them back together with the same offset so that the audio and video are in sync again. I used the following command:
ffmpeg -i /path/to/dvd.mp4 -itsoffset 00:00:10 -i /path/to/dvd.mp4 -map 1:0 -map 0:1 -acodec copy -vcodec copy -acodec copy -vcodec copy new_dvd.mp4

…and no matter how I arrange the command it just ignors the “itsoffset” parameter. You’ll note that in the above example I have offset it by 10 seconds (which is crazy) and there is still no change, the audio is still out of sync by the original amount.

I've been using this [ffmpeg audio/video manipulation](http://howto-pages.org/ffmpeg/) and I just can't get it to work. Googling around has yielded no results. Any help would be greatly appreciated! Thanks!

Hi
I’ve had much better success with umm backing up my DVD’s with handbrake from the packman repository.

The issue isn’t backing up the DVDs as the MPGs that “k9copy” creates are absolutely fine, in perfect sync and original quality; the issue is converting these MPGs to MP4s. So, largely, where the MPG came from in the first place is kind of irrelevant. The MPG announces to players that it has an offset of, say, 0.2 seconds, and the player plays it fine - whether that be VLC on openSUSE or WMP on Vista. I just can’t seem to get the sync correct in the MP4s, any ideas?

Hi
That’s why I suggested Handbrake will do the full conversion in one step
(it does use ffmpeg as well).


Cheers Malcolm °¿° (Linux Counter #276890)
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On Fri, 02 Jul 2010 20:26:02 GMT
Guymer <Guymer@no-mx.forums.opensuse.org> wrote:

>
> The issue isn’t backing up the DVDs as the MPGs that “k9copy” creates
> are absolutely fine, in perfect sync and original quality; the issue
> is converting these MPGs to MP4s. So, largely, where the MPG came
> from in the first place is kind of irrelevant. The MPG announces to
> players that it has an offset of, say, 0.2 seconds, and the player
> plays it fine - whether that be VLC on openSUSE or WMP on Vista. I
> just can’t seem to get the sync correct in the MP4s, any ideas?

-async 1

perhaps?


Cheers / Saludos,

Carlos E. R.
(from 11.2 x86_64 “Emerald” GM (Elessar))