Audio watermarking consists of inserting information, usually in the form of a binary code, throughout a piece of audio (e.g. music, broadcast radio, advert or movie sound track). The information is incorporated as part of the audio, but in a manner that is inaudible, so the original sound is undisturbed. The information, therefore, travels along with the audio wherever it goes, whether distributed on a CD, broadcast over the air or downloaded as an mp3. The information remains with the audio and survives all the manipulations, such as compression, dynamic equalisation, A/D and D/A conversions that can happen to audio on its route from publisher to consumer.

The audio watermark information remains available for extraction at any subsequent point on the route taken by the audio. In effect audio watermarking is like providing an invisible, inaudible bar-code for the audio. And just like a bar-code an audio watermark can be used for many commercial purposes.

Forensics

This is a commercial proposition that uses the watermark to keep track of the places a piece of audio has reached in its processing and/or who has responsibility for it.

Monitoring

This is a commercial proposition that uses the watermark to automatically monitor when, for how long, and on what channel a piece of audio was broadcast.

Xaudio - Interactive Audio

This is a commercial proposition that uses the watermark as meta-data so that consumers can readily access interactive applications configured to the audio being heard by using web-enabled mobile devices, such has mobile phones, PDA's etc.