Somebody please explain why audio sync problems occur?

[dbjames]

I'm copying my old VHS tapes to DVD, using Dazzle AVC and Pinnacle Studios. Video capture to MPEG is fine, but I can't successfully burn the DVD for many of the recordings. I get mild to severe audio sync problems. I've been in contact with Pinnacle support many times and all they can say is 1) close down all backgroung running tasks or 2) use a dedicated harddrive for rendering/compiling. I've tried everything, including 3 different PCs with Windows ME, XP Home and XP Prof. It seems that the more powerful laptops with XP are actually worse than an old 1Ghz PC with Windows ME. Beats me.
Anyway, in an attempt to solve this - could somebody please explain how this problem happens? The captured MPEG is fine, but the resultant VOB files are bad. What's the technical reason for the audio and video being out of sync ? Any help appreciated !!

[lordsmurf]

The #1 reason for audio sync problem is because you are dropping video frames, but not audio frames. There is no way to fix this aside from capturing it again, without video frame loss.

Your biggest problem here, however, is Pinnacle products are trash. That Dazzle is an infamous piece of junk.

[dbjames]

Not sure I understand that. All my video captures are with some amount of Video Frame loss - sometimes 800 lost frames in a 2 hour movie. BUT the audio sync problem only occurs with SOME of my captured MPEGs.. and, to be honest, in recent experience, the lower the number of frames lost, the bigger the audio sync problem. Some really dubious captures result in perfect DVDs. ??????

[dbjames]

and just to add more info... sometimes when I get audio sync problems, I just run the render/compile again and Presto! it's OK on the second or third attempt. That doesn't suggest there was a problem with the capture. It's just that some MPEG files just refuse to be rendered/complied to correct VOBs however many times I try. And the attempts give random results - sometimes terrible, sometimes just a second or two out of sync. Again, that doesn't sound like a problem with the capture....

[lordsmurf]

All my video captures are with some amount of Video Frame loss - sometimes 800 lost frames in a 2 hour movie. ??

This is a major problem you have on your hands.

[dbjames]

OK, I've asked this question in this forum twice now, but nobody seems to have an answer. Let's go back to the basic question. What is the technology involved in rendering/compiling ? Why does a perfectly good looking MPEG file end up as a VOB file with audio and video out of sync ?
If I could understand the rendering/compiling process I might have to chance to figure out how to solve the problem.

[guns1inger]

VOBS are the result of the authoring process. All the data required - video, audio, subpictures, menus etc. are compiled according to the dvd specification.

If you are dropping frames then you have poor quality source. Any dropped frames are a problem, but the amount you are dropping is very high. Even if the mpegs appear to play correctly, they will obviously be affected by this. Unti you can find a method that allows you to get a clean transfer of your tapes into your PC, there is little point trying to pursue other causes.