*_* The magic words have been said.... huu huu huu....
Indeed, Avisynth is good stuff. I'll admit, though, there's no guide I've actually seen to make AMVs directly from Avisynth. Fortunately.... you have someone who's had some experience.
A word of caution, though: Avisynth does have a bit of a learning curve. On top of that, there's no GUI... everything you do, from a resize to a crossfade, is written into a text file. It takes a lil while to get used to the syntax.
On the upside, though, you have incredible precision over what you want in your video. Literally, precision down to the frame level that's 100% reproducible.
"In the beginning there was darkness and void. And then
The Encoder said 'BlankClip(color=$FFFFFF)' and there was
light. The Encoder looked upon the light and saw that it
was good, for it was RGB32."
(although there has been some debate over the Encoder's
choice of container, since Life doesn't support any form
of rewinding.)
--The Darkhold Accord