Algorithm for matching songs

Say I have 20 songs in my iPhone's music collection

A song comes up on the television which might or might not be an exact duplicate of a song I have in my collection.开发者_StackOverflow中文版

( not a cover, the exact same song -- this should make it a little easier )

I record 20 seconds out of this song using my iPhone.

I need an algorithm to detect whether this song matches some song in my collection.

This is my first port of call. As research yields results, I will add an answer to my own question, or edit the question.

So this is my question: how to accomplish this task? Is there any commercially or freely available software? Are there any documented known methods?

I'm imagining the first step will be to process source and target sound waves into a series of vectors ( maybe cepstral coefficients? ) and then perform some sort of pattern matching.

maybe I can hijack some well-known matching algorithm?

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http://echoprint.me/

this is open source and already contains a library for use with iOS

it looks like it is ready to run