Combine audio and visual

This took some experimentation and lengthy chats with GitHub Copilot to figure out how to convert the midi to audio and the animation in such a way they could be combined.

I ended up using bash for this, as my experiments with R wrappers failed.

Convert the midi to audio

Using timidity and ffmpeg:

timidity midi/wikisource-contrapunctus-subject.midi -Ow -o - | ffmpeg -i - -acodec libmp3lame outputs/av/audio.mp3

Combine audio and visual

Using ffmpeg:

ffmpeg -i outputs/av/animation.mp4 -i outputs/av/audio.mp3 -c:v copy -c:a aac -strict experimental -shortest contrapunctus-i.mp4

Unsolved problem

Somewhat disappointingly, the first edge drops from the animation due to the self loop.

(Sound on.)