Matteo, This is a problem that continues on and on.
I have had the same problem and have found I can get the best results with viDrop.
Download link:
viDrop v0.55 AVI XVid Converter.
I found us 22FPS, 300 or 308 bitrate, mp2 codec 128 bitrate.
You may have to put an extra parameter in the mencoder which is -
audio-preload 0.8 -delay 0.1
Read the link by it's author:lokster
http://www.mympxplayer.org/free-open...rs-vt7071.html
hope this helps
ediii