I'm trying to get it to play the movie at
http://spezzafer.home.att.net/sm64.zip , but it seems to work completely randomly.
So far, I haven't found any logic whatsoever as to what settings I need to have with the plugins so that the movie plays.
About 30 tries ago, the movie actually started when I set the "interpreter" mode on in the RSP plugin. Excited, I turned it off to test whether it was the cause, and the movie desynced again. I turned it again on, and the movie still desynced. So that much for that theory.
This is as far as it gets. The demo will continue to run, and eventually the hand icon disappears.
To me, it seems like there's a 98% random chance that in the very beginning, the emulator will fall several frames behind the movie, causing the movie to attempt to start the game (click Mario's eye or whatever) before the game allows it.