WIRED did an article about the new YouTube Music App and the person interviewed said that they already use this kind of AI.

The app combs through the huge pile of music in the entire YouTube collection and surfaces all related content, whether that’s a fan video of the song you’re currently listening to, a live concert, a lyrics video, remix, or cover by another artist — all labeled. Fowler says the app can do this by leveraging YouTube’s smart Content ID system — an automated system originally for identifying pirated copies on the site. It also has a “Melody ID” algorithm for songs, Fowler says.

http://www.wired.com/2015/11/youtube-music-opens-sites-enormous-music-collection-to-all/