[Kylene Arnold]

In case anyone else has this problem, I figured it out. It was a combination of Apple’s inconsistent signal timing during periods of high computer use and its power management system cutting the feed to the external monitors during periods of low computer use (despite the laptop screen itself staying active with the video feed). Swapping the first Blackmagic converter for a Decimator MD-HX fixed Apple’s inconsistent signal timing and adding the Amphetamine app fixed the power management quirk.

[Kylene Arnold]

Yes, I admit it. I’m a recovering FCP user who still slides back into old habits once in a while 🙂 But many thanks to everyone for the help. My client thanks you too — both for improving his project and allowing him to keep the illusion that editors are also magicians.

[Kylene Arnold]

I had already tried resampling the audio in Soundtrack and resyncing without any luck, but decided to try transcoding the file straight to ProRes at 48kHz and it did the trick! Thanks so much for your help!

[Kylene Arnold]

Thanks for your quick response. That was my first thought as well, since I usually convert everything to ProRes. However, the transcoded file didn’t stay in sync in Quicktime OR FCP (whereas the mp4 at least stayed in sync in QuickTime). I transcoded it using its native 44.1 kHz, but no luck.