Animated Music

So, I just rediscovered the Music Animation Machine (those samples are worth viewing, BTW). Inspiration struck! With MIDI<->CSV, I am trying to write a tool to automatically convert a MIDI into animated music. Since I'm currently learning Python, that's the language I'm using.

So far, I've manged to get the MIDI to video conversion working, but the video has no audio. Despite searching, I can't find a free tool to convert MIDI to WAV or MP3. Surely it can't be that difficult? Any suggestions you might have would be welcome.

Update: there are several ways to record anything that your computer plays as a WAV (the Winamp method appears to fall into this category). A command line utility to create a WAV from a MIDI without playing it is quite a bit more rare. At the moment, I'm looking at a tool called TiMidity++.