Ears On

The file format that turned music distribution into free-for-all has acquired a watermark. Actually, a method of embedding digital rights management into MP3 is nearly two years old. But this latest wrinkle is not a thou-shalt-not anti-copying flag. It's more a method of identifying who has been doing what with downloads. A combination of psychoacoustic manipulation and spread-spectrum modulation makes the watermark inaudible to human ears, but it can be picked up by a watermark detector, and can survive both encode/decode processes and analog transmission. According to the Fraunhofer Institute, developer of both MP3 and the new watermark, "watermarking can provide a useful mechanism to track illicit copies or to attach property rights information to the multimedia content." Don't say I didn't warn you.