Audio Sync problems... HELP!

[Jaime Valles]

Hello, all. I'm finishing post on a feature with FCP4 and ProTools LE MBox. The audio mix is finished, and everything sounds great. The problem is when I take the final stereo audio AIFF file and bring it into FCP4, the audio isn't in sync with the picture.

The sound mixer and I have a hunch that it has to do with framerate issues. The film was shot with a DVX in 24pA, and was edited in a timeline at 23.98fps. Once finished, the final edit was exported as a true 24fps Quicktime file, and this was used in ProTools to do the sound editing and mixing. Everything worked great. But now, when I use THE SAME 24fps Quicktime movie in FCP4 with the AIFF bounce down from Protools, the sound doesn't sync. It seems to play back faster than the video, and I can't figure out why.

The sequence is set at 24fps, and I know the movie is 24p because it doesn't need rendering in this sequence (if I put it on a 23.98 or 29.97 sequence, the movie needs rendering) so I don't understand why it syncs perfectly in ProTools, but not in FCP4.

So that's it. Any help or advice would be really appreciated. We're almost at the end of making this film, and the only steps left are fixing audio sync, and color correction. Please help me put an end to the madness!!! :cheesy:

 

[dolph2000]

I'm not very into Protools but, have a look if the sync problem has the same amount of frames in the beginning as in the end. If so then you sync it manually. I sounds too easy but you never know, good luck

 

[ullanta]

Well, a quick 'n' dirty solution would be to bounce the movie with the audio from ProTools rather than FCP. If FCP doesn't play it nice for color correction, then export from FCP when cc is done and then bounce from protools with the audio...?

 

[Jaime Valles]

I'm not very into Protools but, have a look if the sync problem has the same amount of frames in the beginning as in the end. If so then you sync it manually. I sounds too easy but you never know, good luck

Yeah, that's the first thing I tried, but the longer the movie plays, the more out of sync it gets. I can adjust so that any given sentence matches the lip movements, but a few seconds later it starts to drift, and a minute later it's completely off again. The audio is playing back at a different rate than the video.

Well, a quick 'n' dirty solution would be to bounce the movie with the audio from ProTools rather than FCP. If FCP doesn't play it nice for color correction, then export from FCP when cc is done and then bounce from protools with the audio...?

Hmm, I didn't know ProTools could bounce down the movie as well as the audio... I may have to give that a try. But I'm pretty sure it's a simple matter of one mouse click to change a setting somewhere and voilá! Problem gone! I just need to figure out WHICH setting to change.

I know the bounce down is being done correctly, because the sound editor took the audio file and the movie file and put both into iMovie, and everything played back correctly on his computer! But when I take the same audio and video and play it on my computer in FCP, the sync is off. It HAS to be some incorrect setting somewhere, but which one? :shocked:

 

[khina]

check your bit rate because I had your same problem a few times before. sorry that's all i could tell you.