A new technology co-developed by TTR and Macrovision. Its aim is to prevent purchasers of audio CDs (and soon DVD and other digital formats) from ripping audio digitally from the CDROM drive to their hard disk.
It accomplishes this by purposely dirtying up the bitstream just enough that most CD player error correction can interpolate it out. However, a CD-ROM drive will either halt when reading the data, or produce an unlistenable result.
According to New Scientist magazine, the technology adds small bursts of noise into the digital stream. To what degree is yet unknown, but according to listeners, the results were unnoticeable.
Many audiophiles however, are not pleased with this idea, as it degrades the original sound, and thus you do not get the full experience of the original recording.
It harkens back to the days before SCMS, when the RIAA proposed that a form of copy protection that applied a sharp notch filter at 3.8Khz. This sudden drop in frequency could be detected by consumer equipment, and thus prevent recording. (SCMS, while I don't like it, at least didn't degrade the quality of the sound.) The problem becomes when a consumer CD player isn't up to par with its error correction (i.e.: it's old, or only has 4x oversampling, etc.), or the lens is dirty, what have you. Then the internal correction can't process the noise properly, and you don't get what you paid for.
This system also poses a problem in the realm of fair use rights.