How to solve audio sync issue on the Mac? (and it is not just by a constant out of sync amount) I downloaded a clip from 56.com or youku.com, and then found that the video and audio is out of sync.  At first, near 6:00, the video is about 0.7 second slower, and I used iMovie to "detach audio" and then drag the audio to play 0.7 second later and saved the video.  However, I found later that at around 50:00, the video was about 4 to 5 seconds slower.  So the video is constantly slower, not by a fixed amount. (I suspect that it is some 23.97 or 24 frame per second issue, but 4 seconds out of 50:00, and that is 0.13% off... (and 23.97 vs 24 is also 0.125%, so they seem quite close).

Is there a way using HandBrake, iMovie, Final Cut Pro, or any other tool to fix it?  I only saw that in iMovie, I can set the video to play at 101% speed, but then it will be too fast.
I made a workaround which works for short clips: at around 5:00 i split audio and resync second part (drag it backwards by around 0.4s so that is overlaps a little with 1st part). If clip is longer than 10 min I repeat operation at around 10:00; split audio again and resync 3rd part, and so on. 

You can do it also for longer clips but it gets more and more tedious