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 CD ripper from the protected CDs, and thus stop the File sharing of ripped music. The techniques used are:

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

=Circumvention=

A copy-controlled 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. (You may choose to temporarily disable this action by holding down the shift key while inserting the CD.)

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. On the other hand, CD-R/RW drives, and similar, can usually access all session data on a disc, and thus can properly read the audio segment. (It has been reported that the fake ToC may also be bypassed by obscuring the outer 2-4cm of the disc with a temporary felt-tip marker.)

The other major obstacle is the 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. (A related problem is that copy-controlled discs will probably be less resilient to scratching.)

Copy Control also does not prevent copying a disc through recording it as audio through a computer s sound card.

Usually a CD-R/RW drive will play the CD 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.

=See also=

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

=External links=