I've no experience with amd64, but I can tell you or suggest a few things: I'm running mplayer-k6 from the marrilat repo. I don't know anything about the repo at UCLA.edu you posted. I'm using the same package of libasound2 that you are. My questions/suggestions: 1. Does ALSA work for other apps? Have you run alsaconf? 2. Does it happen on stock Debian kernels? 3. What's your sound card again? :)