Well .
avi files aren't all compressed the same way, unlike .wmv. This means the video's vary greatly, the most common .
avi files are encoded by
DivX and
Xvid.
Sadly for you I'm a mac user so I have no idea on how you'd go about seeing how the
AVI file has been compressed, this converter seems like a good place to start *
http://www.videora.com/en-us/Converter/iPod/* if this doesn't work, try experimenting with various converters, I generally type in "avi to iPod" in google and give them all a try.