Luke has not responded, but I would like to jump in here because I have the same problem.

Using BiaB Version 2021 (842) 64 bit on Windows 10 Pro with all the latest MSFT patches.

I have tried all the solutions mentioned in this forum, but the audio is way out of synch with the video. As a consequence, the lyrics and notation on the screen do not keep up with the audio... and that is super annoying.

I have experimented with different frame rates and codecs. I've also tried MP4 conversions of the AVI file with Handbrake. Nothing seems to work.

One forum member suggested video editing, and I certainly could do that, but I'd rather have the audio and video synched up from the start, rather than have to mess around with it.

It seems that this problem has been around for a while, so the fix may be difficult or elusive. Nevertheless, I would be happy to help you solve it in whatever way that I can. My reason for offering help is purely selfish: I need this functionality to put my songs up on YouTube! Yes, there are workarounds, but I would prefer not to go that route.