Chromaprint computes “features” roughly 8 times per second. You can do a brute-force search checking different times in a song or potentially do some more fancy indexing once you have the features.
(I did some experiments with Chromaprint - described here, https://kenschutte.com/phingerprint/)
Cool experiment. I suspect your version would be far more permissive in matching than Shazam, which makes sense for your test case. Shazam's fingerprints are a lot more specific, e.g. they would differentiate different mixes of the same recording, potentially even different masters.
