Bizarre sync problem

I have a 97 minute feature. Shot HDV. Edited ProRes. Exported via Compressor using MPEG 2 and Dolby. Using Mac Octo.

On the resulting DVDs the 2 pop is in sync, then it loses sync by about 3 frames for about 10 minutes, comes gradually back into sync and then, about 10 minutes before the end, creeps out of sync by about 3 or 4 frames again.

I have checked the original FCP timeline. Perfect sync all the way.

I have checked the Exported ProRes file in FCP timeline. Fine.

But when I pull it into DVDSP, it is out of sync when I look at it in the simulator and burns as described.

I have tried compressing sound and picture separately, but it doesn't make any difference.

Can anyone advise me?

Wacky, huh?

Harry.

Yeah. That's wacky. Are you on FCP 5 or 6?

It does sound like a compressor problem to me. Can you import the MPEG and Dolby (hmm have you tried the other option- AIFF?) into FCP and see what happens there?

Also, is it the audio or video that is wandering? Anyone know how to tell?

Coming back into sync? What are the audio sampling rates for all your audio clips, dialogue AND music included. Did you perform an audio mixdown?

I didn't do an audio mixdown because I exported it as QT movie and it remains in sync at that point. It only loses sync either in compressor or in DVDSP.

Thanks for the reply

Harry.

PS. I am currently trying AIFF to see how that goes; thanks for the suggestions.

H

if it's a self-contained mov file, there shouldn't be an issue if it's in sync there. You could try twiddling in QTpro. Heard some guys had some interesting results...

Well, I know it should be ok. I'm currently redoing the sound as AIFF to see if that makes a difference. It's very odd.

I HATE THIS!!!

Harry.

if it's a self-contained movie file, the audio should be rendered in linear pcm 48khz in sync with the visuals, but carried as part of an mov file. Which is technically the same as your aiff file.

If it's NOT a self-contained movie file, then it merely links itself to the clips in your storage device/timeline. So it could get tricky especially if you're working with mixed media (48khz/44.1) and also a multitude of audio tracks (more than 8).

An aiff or wav file preserves sync pretty well... so that's also a pretty safe bet

Aha! It IS a self contained movie file, but I think I chose 44.1 in DVDSP. Maybe I should have chosen 48???

I'll fiddle around.

Thanks for the reply

Harry

Audio for DVD, DV, tapes for broadcast are all at 48khz 16bits. Audio on CDs are at 44.1khz, so they need to be converted to 48khz before you start working with it. The only stuff going at other bitrates are Cannon's sampling rate issue (47.99khz), and DVD-audio which is at 96khz 24bit, and crummy sounding 32khz 4 track audio DV, which records 4 tracks by compromising sampling rate. Vinyls, Cassette tapes, Hi8s are all analog, so sampling rates are whatever u set it to when you capture.