How is YouTube id'ing copyrighted audio immediately?

[brassplyer]

I tried uploading a video of a particular singer and got a copyright notice on it immediately. Blocked in certain countries (apparently any country on this planet), audio owned by so and so.

I know they do tag a file forever presumably based on the metadata, so I tried uploading a newly created version this time didn't include any identifying info related to the artist or song. It still got flagged.

Are they using some kind of waveform matching algorithm to id a song based on what the audio "looks" like?

[guns1inger]

I am guessing it is a more sophisticated version of the concept behind the iphone app that identifies songs on the radio (and then sends you to the itunes store to buy them . . . ). Yes, it is based on analysis of the audio itself, not the meta tags

The official blurb is here

[jagabo]

Yes, they are fingerprinting the audio.
http://www.csh.rit.edu/~parallax/

[olyteddy]

GraceNote is a company that specializes in that. WinAmp uses them for Auto-Tag. Works pretty good...