Thursday, August 28, 2014

A Musical Random Walk

I just read a blog post here at MSU about The Infinite Jukebox, a web tool that will analyze a song (either one you upload or one from their library) and map out links between segments of the song that have approximately the same beat. You then see a visualization of the song as a loop, with the links (arcs) added, forming a directed graph. (The visualization does not display arcs as arrows, though, just as, well, arcs.)

When you replay the song in The Infinite Jukebox, as it passes the tail node of each arc, it randomly chooses whether to keep going on the original path or cross the arc and continue playing, along the original path, from the head node. Thus the "infinite" part of the site's name -- the song will continue until you stop it.

I don't know the algorithm they use for playback, but it appears superficially to be a Markov process, so perhaps this really is a random walk over the song's graph.

If you want to try it out, I can recommend The Trashmen's version of "Surfin' Bird", which I was happy to discover is in the site's library. The randomly looped version sounds suspiciously like the original (which is what I expected). Although the visualization of the progress through the song is interesting, for the full multimedia experience you'll want to have the You Tube video playing (muted) on a second screen.

Sadly, their library does not include "Papa-Oom-Mow-Mow" by The Rivingtons, and I don't happen to own a copy, so I could not compare the action of The Infinite Jukebox on that with what it did to "Surfin' Bird". As I listened to the looped "Surfin' Bird", though, I couldn't help but think "and thus another enhanced interrogation technique is born".

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