Thanks for reporting. There are many ways to screw up audio/video sync Some of the problems have been fixed, some may still remain. I'll try to watch Nokia_N810.avi more carefully to check for audio/video sync problems on it.

In the mean time you can experiment with trying different audio drivers (esd or alsa instead of sdl) to check if they work better. Probably audio driver latency is not properly compensated. Do you see audio/video sync problems with all videos or only with some of them? Can you report a version of mplayer which worked better on the same OS (on different OS), so that we could look at what has changed since then?