When viewing that 4 minute MM video straight up, the audio seems to desync for me too. However, it lines up again if I stop the video and play it again. It could just be that my computer is slow, but it could also be due to the high data rate to play the audio and video together.
Here is data from GSpot about the 4 minute video.
Container
Note: 410 bytes unneeded bytes at end of file
AVI v1.0
Video: 33.9 MB (45.14%)
Audio: 40.8 MB (54.39%)
AVI Overhead: 360 KB (0.47%)
Audio
PCM Audio
44100Hz 1411 kb/s tot (2 chnls)
No Codec Required
Video
Codec: H264
Name: H.264/MPEG-4 AVC
Length: 4:03.138
Frames: 14,588
kbps: 1170
Frame Quality: 0.254
Frame Rate: 59.999
(other detail on video size)
In other words, the video is huge because the audio is PCM, or uncompressed.
Either way, it is possible that the audio might synchronize after all. Just need someone with a faster computer to test this.