Be careful not to get sued like that guy who posted an article about detecting songs and got sued by Shazam, even though everybody knows about FFT (I've been doing something like that for my BSc)
Any idea if that article is still available? Or do you have any good resources for implementing FTT? I'm working on a project to compare sound clips for similarity, but I haven't grasped an effective way to accomplish that yet.
I just implemented math from a textbook. Obviously, you will need to break down your song into smaller chunks. Then compare the frequencies of these chunks. When sufficiently many chunks are "close" (you'll need to define some measure of similarity), then songs are "the same". P.S. That article has been taken down by the authors after repeated threats from Shazam.