Copy Control - Circumvention

Circumvention

A Copy Control disc will appear as a mixed-mode disc, with audio and data content. Under Windows, inserting the disc will usually autorun an audio player utility, which plays the DRM-protected audio files provided. This can be temporarily disabled by holding down the shift key while inserting the disc on Windows XP and earlier, users of Windows Vista and 7 may simply choose not to run the DRM content.

The ability to extract the CD-Audio tracks is otherwise largely dependent on the disc drive used. The first obstacle is the "fake" Table of Contents (ToC), which is intended to mask the audio tracks from CD-ROM drives. However CD-R/RW drives, and similar, can usually access all session data on a disc, and thus can properly read the audio segment.

The other major obstacle is the incompatible (and technically corrupted) error-correction data. Again, the effect of this is dependent on the disc drive; some drives will be able to read the data without problems, but others will produce audio files with loud pops every few seconds. As a consequence of having faulty error-correction codes, the discs may be less resilient to anything that might cause a read error, such as dust and scratches resulting from normal use.

Copy Control also does not prevent copying a disc by recording it as analog audio through a computer's sound card, which only causes a slight degradation in audio quality. More substantial is the loss in recording speed. This weakness, inherent in all digital copy prevention systems, is known as the "analog hole". As an alternative that does not rely on the "analog hole", it may be possible to copy the content using a digital link while playing it through a sound card that has a digital audio output.

Usually a CD-R/RW drive will play the disc but with occasional stops (about every 10 seconds) and DVD-R/RW drives will be able to read the data without problems and can be ripped straight to the PC. CD-ROM or DVD-ROM drives in a computer will usually refuse to play the data except in the provided player.

Systems other than Windows, however, can easily play Copy Control discs, as many players on Windows are proprietary and respect the copy-restrictions. Similarly, the auto-launchers are only written for Windows and will only ambush Windows users (this can be mitigated by disabling autorun). There is little that can be done to stop a user that is not running Windows from ripping a Copy Control disc.

In Linux, Copy Control discs are easily accessed through cdparanoia or any other software that uses it, such as the KDE "audiocd:/" service.

In Mac OS X, these discs are easily accessed through iTunes and QuickTime (When a CDDA track is dragged to a folder other than the CD, QuickTime automatically converts it to AIFF, which is a lossless PCM format).