VBA avi recording sound lag

I'm using VisualBoyAdvance 1.7.2. Everything works fine for me, except avi recording. After recording perfectly for about one minute or so, the sound begins to lag/delay. The longer the avi file, the more delay. In a 6-minute movie I recorded, it has about 7 seconds of sound delay near the end! I've tried many different ROMs, many different avi codecs, and the result is still the same. What am I supposed to do?

Upgrade to 1.8.0 and see what happens. There's an option "Use old synchronization" in "Options"-> "Sound" menu btw.

Wel... 1.8.0 beta 2 with Old Syncro-whatever doesn't work. 1.8.0 beta 3 doesn't work TOO, and it also has sound lag while I'm just playing normally! So what's wrong with this?