Why is sound out of sync?

[rt]

I have been trying to backup my dvds to avi using DVDDecrypter (from Gordian Knot package) and then Auto GK to encode etc. On one particular copy, the sound in the avi is out of sync by about a second or a little more. The VOBs on the HDD play in sync. Why does this happen and is it easily curable? The sound is ahead of picture. How do I find out exactly how far out of sync it is?
TIA,
RT

[Kb_cruncher]

There is usually an audio delay in the dvd audio(Ac3)which needs to be taken into account.I am not sure if autoGK has an option to do this or not as i do not use it.You can do it manually by extracting the audio with DVD2AVI and then use BeSweet to encode it to your chosen format and then mux it with the video that autoGK gives you(you will need to take the audio already in the avi out first using Virtualdub).

[manono]

Hi rt, and welcome to the forum-

I'm not sure what caused the problem, but it's easy enough to fix.

Open the .avi (complete with the out-of-synch audio) in VDubMod (hit "No" when it gives you that stupid message upon opening the file). Then set Video to Direct Stream Copy. Then go Streams->Stream List and you'll see the audio track. Right-click on that and go to Interleaving, and there you'll see the Audio Skew Correction box. You said the sound plays ahead of the video by about a second, so enter 1000 ms Delay for your first try. If the Audio is MP3, then you can leave the Preload and Interleave boxes alone. If it's AC3, then set them both to 96 ms, maybe. Then OK your way out of there, go File->Save As and give it another name. Wait a minute or two and you'll have a new .avi. Check it out for audio asynch, and then try again. It may take three or four tries to get it right. And it's a bit easier to know if it's good if you can cue on a sharp sound, like a door slamming, or a gunshot. If you have to test with lips moving, try and find a closeup.

If your AutoGK is up to date, make sure your DVDDecrypter is also. At the moment it should be version 3.1.9.0. And if you didn't rip with DVDDecrypter set to IFO Mode, then that might account for the audio asynch. IFO Mode is no longer the default setting.

And there's always the chance that the asynch is a playback problem, particularly if your computer is borderline. To test that, you might try and play it on a friend's computer. Or try a different player, particularly one that uses relatively little computer resources, such as BS Player. But you said that it's happened only once, so that's probably not the case.

[rt]

Thanks - will try soon - the computer has been down for a few days.
RT