Audio Sync Drift Problems

[rallymatt]

I'm having some decent problems with audio sync drift over a few minutes. By about 4 minutes the sync is off about 2 frames and no longer matches properly.

Audio was recorded with a FR2-LE in BWF 48KHZ/16

Video was on a 5D and 7D both recording 24FPS (23.98)

Sequence settings in final cut are 23.98 FPS, 1920x1080, ProRes 4444 which matches my imported clips.

I don't quite get why it is drifting when everything seems to match up.

I tried converting the BWF files to MOV using Sebsky tools, but that yields the same result.

I have done 8 minute clips before using the FR2-LE and my 7D exact same settings with no issues so I think it has to be sequence settings or something, but I cannot seem to find any difference from my previous projects. Only thing is I have upgraded to Final Cut 7.0 since then.

Any ideas?

EDIT: I tried dropping the clips into Premiere and there is no sync issue, even on a DVDPROHD timeline. This tells me it has to be a Final Cut sequence issue or something, but I cannot find anything wrong.

 

[rallymatt]

Ok, an update for those that may have the same issue.

I dropped my BWF files from the fostex into Soundtrack Pro and exported them as AIFFs. Same settings 48KHZ/16

Re-imported into FCP and it syncs fine now. WTF. Anyone know why that is? I really dont want to have to re-export every audio clip from Soundtrack pro.

EDIT: Well, it appears Final Cut has tagged the XML of my BWF files as 25FPS. I don't know why, and I can't figure out how to make it tag them as 23.98 instead.