007/xvid->dvd/bad frames/sync/why vid longer than snd ?

[jmbuis]

I am trying to convert an xvid + ac3 file to dvd mpeg2 + ac3
but the resulting dvd play in sync at the beginning but gets progressively out of sync.
I figured it was because of bad frames that virtualdub has detected, but then how come it is the sound that is ahead of the video. I thought with the bad frames would get a video stream ahead of the audio stream. Oddly enough, the audio stream is about 1 second shorter (30 frames) in length than the video

Anyone? Weirdly enough, Mplayer Classic plays the xvid perfectly in sync. Too bad it cannot frameserve...

Here are the different steps I carried out :

- extract ac3 stream from avi with avimux
- convert video stream to mpeg2 (with tmpgenc / tried once direct avi source and once frameserving with virtualdub => same result)
- authored with dvdmaestro

- I have also tried converting the ac3 file to wav and stretching it out to have the same length as the video stream, then encode it back to ac3 and author with that corrected stream : the beginning and end of the film were in perfect sync but then in some parts in the middle, it was out of sync again, and severely

- I have also tried fixing the avi with virtualdub (actually I am not sure whether virtualdub replaces the bad frames or just removes them?) but it doesn't change anything with the new "fixed" avi

- now I will probably try and work with the video stream and the wav stream and hunt one by one each bad frame and cut the whole thing into pieces...

any other idea? how does avisynth handle bad frames ? would it be a better frameserve than virtualdub in that respect ?

Thanks for any help

Jim

[jmbuis]

for information, this is what I ended up doing :

- decode all ac3 to uncompressed wav
- hunt for bad frames in the avi's (using virtualdub-mp3-freeze)
- cut these bad these frames out
- with the resulting chunks of avi's, check that they have no bad frames and adjust audio interleave so that they are in sync
- with virtualdub recompile all those chunks into one single big avi (with uncompressed wav)
- frameserve this big avi to tmpgenc to encode into an mpeg2 dvd compliant video stream
(I had to frameserve because if when I compressed by opening the avi directly in tmpgenc, the result was jerky in some parts (known divx/xvid issue))

the result was just great and quasi seamless