deho said:
Well, a lot of editing needed to be done. I had both, the original and the Laserdisc audio, open in Audition and they weren't in sync every 2-3 mins, sometimes even after a couple of seconds.
If it goes out of sync all the time, there is an error. The two (three) sources are may be in different formats (different speed), or one version has many framecuts, perhaps to get rid of damaged frames at scene changes. The third option is that there's a fluctuation in one of the recordings. But there is something for sure.
The best case is the fluctuation, but only if the phenomenon is indeed insignificant. If it goes out of sync by 10 milisecs every 2-3 minutes AND it goes back to sync BY ITSELF in the next 2-3 minutes, it should be fine. But from your description it doesn't seem that simple.
The time stretching method really has to be the last resort. Ever since I realized how wrong it is, I've never used it anymore, for any movie to fill up holes in the audio.