Audio desyncs after a while

[F-Man]

I have tried re-encoding a 20 minutes long video 3 times using AVC and MPEG-4 SP, and each time the audio desyncs slightly after 9 minutes in the video. It's a cartoon and the lipsynch starts failing there. I haven't heard any glitched spot in the audio track, so I'm thinking it may be progressive and only starts being noticeable there.

Anyone have experienced this? I could probably tinker around with some app and import the previous audio track onto the video, but frankly I don't know any that can do this with MPEG-4 containers.

EDIT: just tried with a 50 minutes long video and didn't get any problem (except that it encoded the audio at 1536kB/s when I specified only 64). Hrm...

[AANASA]

I am having troubles as well... No luck for me Ive already Posted my problems with divx but no one seems to know/post

[XerXes]

First make sure that when your editing a profile you "SAVE" it. Alot of time when editing a profile I will forget to hit the save button. Nothing will be saved. Next try to add "-async 1" without quotes in the custom flags box. 9 times of the 10 the A/V sinc will be perfect. But also keep in mind that it can double the amount of time it takes to encode a video.

Hope that helps