I've completed work on a complex edit. I have made two exports:
I have exported the video (with audio) as a ProRes file with 48kHz 16-bit PCM audio.
I've also exported the sequence as a 16 bit PCM WAV file 48 kHz.
Both exports were from the beginning of the sequence to the end.
We recombined the files in After Effects on another Mac. The same project settings (25 fps video, 48 kHz, 16-bit audio).
The audio on the two files was out of sync, by less than a frame, but definitely out of sync.
I re-imported the files into a new Premiere project on my mac to check.
The waveforms were visibly out of sync, by less than a frame.
My question is why, and what's the right way to export audio only in a file which will correctly maintain sync?