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audio sync drifting

I am still editing in FCP 7 (on a power mac, OS 10.6.8). I transcoded interview footage from my iphone to Apple PR 422. Both the original and the transcoded 422 footage plays in sync with the Quick Time player, but when I bring the 422 into FCP 7 it drifts out of sync. (The rate of the original and the 422 is 29.97)


I first transcoded using my MacBook's own encoder. When I found the sync problem, I then transcoded using MPEG StreamClip which I've used MANY times to transcode to Apple Pro Rez 422 with no sync drift problems. But no. Ugh. Any help with be much appreciated!!

MacBook Pro 15″, macOS 11.6

Posted on Nov 11, 2023 2:21 PM

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Posted on Nov 12, 2023 11:29 AM

The conversion frame rate is on automatic, basically passing it through, though it can't do it exactly like the original. I can't remember if you can control this in Streamclip, but in Compressor you can specify an exact frame rate, like 29.97 or 30 (fractional frame rates are ridiculous). The output file will be a constant frame rate and more likely, though not certainly, able to maintain sync, because the sample rate is constant.

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audio sync drifting

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