That was an excellent suggestion. Unfortunately, although the picture looks great, maybe even better than the previous resolution, the audio remains out of sync with the picture.
I have been able to remedy the problem by adjusting "AV Sync" on my Sony Blu-Ray player. In that control panel, not shown in the manual as far as I could tell, a person can delay the audio track up to 120 milliseconds. I used the maximum setting and everything seemed to be in sync.
From what I read on the internet such AV Sync problems are not uncommon even with commercial discs. Furthermore, there doesn't seem to be one setting that works for all discs.
Unfortunately, my disc is headed for a film festival. They may or may not be able to adjust AV Sync but they also may not have time to do this in the midst of all the films they're showing. Such a shame. The DVD version of the same QuickTime file is perfectly in sync. That's probably what we'll be showing.
If you or anyone else has additional ideas to solve the core problem, audio-picture sync on a BluRay disc, please continue helping.