Audio drifts out of sync - Shure MV7 and iPad via Camo
Some recordings made with a Shure MV7 USB mic (connected to the computer) and iPad (using the Camo app, connected to the computer) drift out of sync. It gets worse as the timeline gets longer.
Strangely, it's inconsistent. In one take, around 11 minutes in, the audio was 30 frames late (at 60fps), but in another take in the same project, after 12 minutes, the audio seems fine.
How can this be fixed?
Recordings made on Macbook Pro, Monterey, Screenflow 10.05.
Playback (where I'm observing the lag) is a MacPro6,1, Big Sure 11.6.5
Make sure USB audio source is 48kHz (some default to 44.1kHz). Use Apple's Audio Midi Setup app to check that.
Different USB sources can drift over time. Try to make sure the devices are on different buses (Mac Pro should have at least two USB buses I believe) as sometimes multiple ports may be on the same bus.
Also, avoid using a USB hub for Camo.
Sometimes you can fix this issue after recording if you apply a speed change to the video to get them into sync. That requires some experimentation with the speed depending on the rate of drift.