Copy control - Definition

Copy control is the name of a compact disc copy-protection system used on recent EMI CD releases in some regions. The system is intended to prevent digital audio extraction from the protected CDs, and thus stop the file-sharing of ripped MP3s. The techniques used are:

• Multisession (Blue Book) information is included which effectively hides the audio tracks from most CD-ROM drives;
• Error-correction codes for the audio data are corrupted, which may introduce audible errors to ripped copies;
• The data area of the disc usually includes DRM-protected copies of the audio content, which are compatible with major Operating systems such as Microsoft Windows.

It should be noted that the techniques used by Copy control make the discs incompliant with the Red Book standard for CD audio; hence, the discs cannot technically or officially be called 'Compact Discs'.

See also

• Cactus Data Shield
• Copy prevention#Copy prevention for audio CDs