AVI to SVCD gradual loss of sync

[captnemo]

I'm experiencing a gradual loss of sync problem and have been unable to solve it. Here is my process:

I use the pass-through capability of a Sony camcorder to convert VHS analog to DV which I send to the computer via firewire and save to an AVI file with WinDV. This process works flawlessly with the exception that the resultant video does not seem to have the same level of brightness as the original video.

Next I run it through virtualdub freeze to look for broken frames - but have never had any.

Next I open the AVI in virtualdub (using panasonic DV codec) and cut out unwanted scenes, process it through the brightness filter to lighten it up if needed, then save as AVI. I then open it in virtualdub again and check it. At this point video and audio have always been in sync. I close out virtualdub.

Next I open TMPGenc, and using one of the guides referenced on this forum, convert to SVCD mpeg2. When I review the resultant mpg file, I notice that the sound gradually gets out of sync towards the end of the file. It is okay until about 80% through 50 minutes of video and then becomes noticable.

I went back and double-checked the avi file and it is definitely okay. I have also used virtualdub to save the audio as a wav and then recombine with the avi during the convert in TMPGenc. This helps but there is still a subtle lack of sync towards the end of the resultant mpg file.

I have also converted the AVI to VCD on another computer using roxio instead of TMPGenc. Same problem.

I don't know what to try next. Any suggestions?

Also is the loss of brightness normal?

Thanks in advance.

[rcb]

It's not uncommon for captured video to look darker on pc monitors - always judge by your "final" viewing source (tv,etc.)

Gradual drifting sync can be a real PITA. There is a sticky at the top of one of these forums that offers some ideas... or a search on "gradual sync" might net you some helpful hits.

Also, I think that SVCD spec call for audio at 44.1 vs 48 for dvd - you might check to see what your source avi is by using Avicodec.. or another possible cause are some dropped/corrupted frames that virtualdub didn't pick up on...

Hopefully another poter can give more/better ideas.