On a recent MacBook Pro 16" running Catalina 10.15.4, I’m finding audio very unreliable in RV 7.8.0 when playing QuickTimes with H.264, DNxHD or ProRes media and embedded audio: either you hear nothing, or you just hear small snippets of audio. Once in a while it will actually play correctly, but then you restart RV or reload the movie file and it fails again.
On the same machine, going back to RV 7.2.5 brings back reliable playback of audio in movie files (minus ProRes which is not supported on that RV version).
I realize that this is not a very detailed report, I only have intermittent access to the system so I haven’t been able to identify exactly which RV version “broke” audio on macOS for that system, but I was curious to hear if anyone else is having these types of issues.