This is very interesting - I see this as an ideal concept to be paired with one of the existing commercial solutions, e.g. Shazam. If you're indexing all the r

This is very interesting - I see this as an ideal concept to be paired with one of the existing commercial solutions, e.g. Shazam. If you're indexing all the random and free stuff out there, you're picking up a lot of material that may have never been commercially released or has not been re-released digitally. At the same time, Shazam, YouTube ContentID, Apple's iTunes Match, etc. have access to an extremely large set of references which (more than you could have) contain 99% accurate metadata. ContentID definitely picks up multiple songs in mixes, as well as pitch changes, with a high degree of accuracy (assuming the master sound recording has been submitted to YouTube). A submission system would be great too, or some way for persons to tag stuff themselves ala discogs, etc.