NeonBible said:

Thanks Chewy. I'll have to try that if it is a permanent change rather than just a timecode flag.

Now is +250ms the right delay I should be setting? I just pulled that number out the air and seems to work out ok. But is there an exact science to getting the right sync? Is the only way to play them side by side and figure it out from there?

I just checked the mkv I made again. Yes +250 or perhaps +200 seems to sync things up again for me in the scenes I mentioned. Although with this delay, when I watch the scene where Laurie is sat in class and answers her teacher, lip sync appears to be off whereas it seems ok with no added delay.

For clarification; I'm not suggesting there's anything wrong with the audio track, clearly several people have it sync'd with no issues. Perhaps there's something amiss with the method I used: Convert w64 to wav using dBPoweramp, mux wav with video using mkvtoolnix.