little-endian said:
Maybe someone can enlighten me here.
Having sincronyzing many audio tracks in the past two years (from BD/DVD/LD/VHS) I always use video as reference - because it's easy and a certain audio track *should* be in sync with its own video track...
Well, sometime it is not true, and one audio track is out of sync (for few dozen ms usually) in a way, while another in the other way...
Plus, add that almost everytime different versions have few frames added/missing; in that case, I leave the audio track in sync with video, and when frame is missing, I delete the related audio, while when there is an added frame, I add a small empty audio bit, or repeat the previous frame's audio if it sounds good; note that each frame is only a bit more than 41ms, and usually this occurs at a scene change, so that empty bit of audio is usually unnoticeable.
...and it's an hard and time-consuming task, in particular if you have to "cut&paste" audio parts from different versions...