I have some audio files. I want to make them available as YouTube videos. But I do not want a static image, like an album cover, appearing all the time. I want some "moving fractal images" video style (but in fact it could be any other "style"). Some media players have this visualization tool. But what I want is to have the video file (with the audio) to upload to YouTube.
How can I achieve this? Which program(s) should I use? Or which commands to type in the command line?