iMovie (iOS) audio sync issues with longer clips?

Has anyone run into the issue in iMovie (iOS) where a single ~20 minute clip will cause the following clip’s audio to be out of sync when exported (it’s fine in the program itself)?

Even with just two clips (~20 minute clip + short clip) and no transitions, the audio of the short clip is out of sync.

(Both clips are at 30 fps.)

Separate audio? What type of camera?

Yes, each clip has its own audio (but not detached from video).

First clip was shot on an iPhone 8 and edited in Adobe Premier; second clip was shot on an iPhone 7 and edited in iMovie.

So if you shoot on an iPhone of any sort, you’ll get a file that is a variable frame rate. So even though you may select 30, 24, or 60fps, it won’t stay that way, which causes the audio and the video to lose sync. Sometimes you’ll get lucky and the frame rate will be pretty close to constant, and other times it will be way off. You’ll need to use something like to switch from variable to fixed frame rate.

Thank you.

I thought about that, but I believe both clips are already at 30 fps:

Screen Shot 2020-05-14 at 2.58.13 PM

Screen Shot 2020-05-14 at 2.58.30 PM


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Yea, it will say that, but in reality it’s probably not lol. But the other thing handbrake may help you with is your audio sampling rate. There are two different samples rates, which may effect how everything lines up in the final mix.

Thank you – good to know about the discrepancies!

FWIW, I redid the test in Luma Fusion and had no audio sync issues.

I might just stick with Luma Fusion for longer projects, though I do like iMovie on iOS overall.

Thanks again for your help!

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