Is there a DOI equivalent for identifying music tracks?
> One of MusicBrainz' aims is to be the universal lingua franca for music by providing a reliable and unambiguous form of music identification; this music identification is performed through the use of MusicBrainz Identifiers (MBIDs).
the complications with the same song appearing in multiple albums (including compilations) would give weird results sometimes, but it is totally useable if you only care about finding basic information.
I don't know how to look up music with a known ISRC, though.