Microsoft Patents Forensic Watermark for Music

The technology, called ‘stealthy audio watermarking’ shows that Microsoft is definitely interested in attracting content providers, but knows little about the reproduction of music. (I know, for many of you, this is not news!)

The very nature of audio reproduction means that anything added will have consequence to what is perceived. Test after test has been provided for other audio questions concerning the effects of adding ‘imperceptible’ information to music.

When compact discs were being readied for release changes made in the coding scheme that were in the ultrasonic range were found to have effects on the audible range – and were changed or dropped. The same was found with infrasonic signals, and also signals in the audible range, but well below the suspected floor of perception. In each case, careful listening revealed differences, and listeners were able to pick the changed music.

I can’t help thinking about how ‘some of the people can be fooled all the time’. This will be Microsoft’s target audience.

The watermarking will be audible, in testing where full range and dynamics are available, which leaves out most digital production other than on some form of disc. MP3 will not reveal it, as it is so limited in quality from the start – perhaps this is the thinking – in that case, the technology may have a bright future.

[tags] audio watermark, Microsoft, U.S. patent 7,266,697, DRM, Microsoft Research, forensic watermark [/tags]