Shazam's music fingerprinting algorithm

This is cool.  Shazam has that groovy service that allows you to ask your phone what music you're hearing in the wild; it does this by taking a sliding FFT of the audio and matching salient points against a database of bazillions of songs it knows.  It's patented, but the authors have published a paper about how it works.

Well, in 2009 there was a blog post about this, and in 2010 Roy van Rijn wrote it up in Java and wrote a very well-thought-out account of the process.  Very good article.  Shazam's lawyers contacted him about it, "encouraging" him to take it down on the theory that even though the algorithm was patented in the US only, van Rijn might be contributing to violation elsewhere - even though he'd literally only written code to the specifications already published in the patent for Christ's sake this stuff makes me so made I can spit but let's go on, shall we?

Anyway, HNN link from this week and somebody else published full working code on Github, so that's why I'm noting it now.  Mostly I'm just fascinated by audio processing but don't have discretionary time right now that's not already spoken for.