I've been trying to make a server that can visualize music (This is what I have so far). That's been successful but I want to try and make it work with youtube videos, and I've found a lot of repositories on github for youtube video to audio conversion that make this reasonably doable, but in order to deploy a server on heroku that can host temporary audio files of youtube videos in the format that I want, I'd need to include ffmpeg in a buildpack and I'm not sure how to go about doing that. This is the heroku buildpack for node.js but I don't really understand how it works.
TL;DR: What steps would I need to follow after forking the heroku-buildpack-nodejs repository on github in order to successfully deploy a node.js server to heroku and run this code?
var conversionProcess = child_process.spawn(
'ffmpeg',
['-i', 'some_youtube_audio.mp3', 'some_youtube_audio.webm'],
{
cwd: __dirname + '/tmp'
}
);
The documentation for this function is on the node.js API, by the way.