2007-02-22

How iTune/Gracenote identify your CD?

In my previous post - The Joyce Hatto hoax? - I mentioned that iTune helped identify a Joyce Hatto CD as a potential fake.

Actually, before this incident, I never thought about how iTune "identify" music. I somehow just assumed that there must be a certain piece of information embedded in a CD (a unique code, e.g.) which would be transmitted to the Gracenote database, which iTune uses, for matching purpose. The matching, I supposed, was done through information submitted by record companies.

That is, it seemed to me that a Joyce Hatto CD of Liszt's Transcendental Etudes would carry a code (say 1a2b). Concert Artist, the label which released that CD, would submit album and track information to the Gracenote database to match that unique code.

If this is indeed how it works, then a Joyce Hatto CD will always be identified as just that, and there is no way to expose this potential fraud.

In fact, from Gracenote's web site, these days music identification is done in a much complex and sophisticated way:

Audio Waveform Recognition Technology: Using audio waveform fingerprint technology, MusicID can identify individual songs or albums in a user's collection regardless of source, format or tag information.

In simple terms, A may disguise himself as B and in posession of B's identification documents, but he still has the fingerprints of A and therefore can be exposed when being checked.

I learned something new today.

----------

To learn even more, including the controversy surrounding CDDB/Gracenote, read Wikipedia's entry on Gracenote.

OK, so there is no unique code embedded in a CD and that CD information was submitted by volunteers/users as well (at least in the early years). But that's not the point here. The point I want to make in this post is, should music recognition was done along this vein, there is no way to identify a recording as fake. There must be some form of fingerprint/DNA inherent in the music itself for this to happen.

Song Recognition Software Uncovers Fraudulent Recordings (Wired Blogs, 21/2/07)
Gracenote Defends Its Evolution (Wired News, 13/11/06)