They identify a currently playing song.
Probably, if the music was released as a track on the game’s soundtrack. Those get included in music databases like MusicBrainz, which is what a lot of those music detection services use.
Some level themes are popular enough to have covers made of them, and if the cover is close enough to the original, it may get recognized. Some are popular enough to be cataloged on their own. For example, Chemical Plant Zone from Sonic the Hedgehog 2: https://musicbrainz.org/recording/cb389ab1-b08e-4042-ab73-8ff63e8a6205
I wouldn’t count on every level from every game being cataloged in a music database, though.
If you have a musicbrains account you can upload music/track fingerprints to help future beings identify audio tracks too.
IME they work when the music was actually released formally as an album and there’s metadata available for “an album you can buy separately”. If it’s just regular video game music I haven’t had any luck.
Seems like it’d be pretty easy to test.



