Actually I was a little mistaken when I said you couldn't do that. I forgot that I'd written this:
http://www.blitzbasic.com/Community/posts.php?topic=33476CopperCircle paid me to write it and he released it for free. Don't ask me for support though. :-)
It may not work on all AVI's. It may not work on all PC's. It should work on all PC's, but there were some glitches with certain commands. For example, playing back at different speeds worked differently on different cards.
Should work for your needs though. Unfortunately for CopperCircle, it didn't do what he thought it would when he paid me to write it.... ie, allow one to adjust brightness and contrast. The MCI documentation Microsoft provides was confusing about that and I still am not sure if any system supports the "overlay" those commands supposedly apply to.