Audio dropping out of sync on export

Hi guys,

Hmm... just exported a short 5 min clip to soundtrack pro to treat the audio. I figured that since it was a simple interview, I could just export the audio file and import it back afterwards. So I did an audio mixdown, and exported it as aiff. When i reimported it, i turned out that the clip started in sync, but drifted way out of sync towards the end. It was quite surprising, so i exported the edit again as an aiff but this time i DIDN'T send it through soundtrack pro, and it was already out of sync. I'm currently on final cut 5.1.0, and a powermac G5, sequence setting is set to 48khz, so are the clips and the export. What else is funny, is that as I zoom into waveforms on the timeline, to compare it with the original clip, the waveform actually shifts.

Word, anyone?

[When i reimported it, i turned out that the clip started in sync, but drifted way out of sync towards the end]

I'm not saying this happened to you, but it did to me-- you have to be careful with some of the insert capabilities in STKPro-- you can *very easily* change the time of your tracks when all you think you're doing is overwriting, say, ambient noise to patch a signal issue.

I'm doing shortform at the moment and I've seen my errors when importing those. What's nice is, they're separate actions you can go back and undo!

Assuming your sample rates are identical in both programs, I'm guessing the tracks somehow acquired new timing.

- Loren
Today's FCP keytip:
Invoke your Favorites bin with Command-6 !

Final Cut Studio 2 KeyGuide? Power Pack.
Now available at KeyGuide Central.
www.neotrondesign.com

Hmm... I rarely can afford the luxury of mixing in stkpro. But thanks for the tip. It certainly wasn't soundtrack pro (or any of the rt effects in soundtrack that i used), since i did a test and exported it without running it through stkpro and was already 9 frames longer than i should be (exactly the length i was out of sync by after stkpro).

I usually use stkpro for mastering, cleaning up noisy atmosphere, etc... But this change in sync/length is very disconcerting, especially when it is just 5 mins in length. And since it went off sync on export, I'm thinking of speeding up the audio tracks when i get back in on monday, which should be barely audible, since the change is mnute. (wtf is going on with the final cut audio export!? )

Just did a test in PAL. Nothing wrong- exported a full 20 odd minute of footage, threw it back in and no drift/sync issues. I'm wondering if it's an NTSC setting. (I'm in PAL country, so great if someone could enlighten me on that). Could it be a 30fps/29.97fps issue? If so, how do i set it right?

thanks

strypes Wrote:
-------------------------------------------------------
> Just did a test in PAL. Nothing wrong- exported a
> full 20 odd minute of footage, threw it back in
> and no drift/sync issues. I'm wondering if it's an
> NTSC setting. (I'm in PAL country, so great if
> someone could enlighten me on that). Could it be a
> 30fps/29.97fps issue? If so, how do i set it
> right?
>
> thanks

I realise this is a very, very old thread, but the problem you're describing Strypes is exactly what's happening to me. Like you I'm also in PAL land, but I'm working on a 23.98 NTSC demo video. The cut is 5 mins long and I'm getting sync drift all the way through. About a frame late after 1 minute then gradually increasing so that by the end (5 minutes) it's 7 frames out of sync (late).

I also did a test with a 5 minute PAL timeline - round trip through STP - and it was dead accurate.

Did you ever find a solution ? I've scoured the STP forum and found many posts about sync problems in STP (but no solutions) - but I've been thinking that it could be my (blissful) ignorance about NTSC.

Thanks in advance.

Mike