The present invention relates to a method of copy protecting optical discs, such as CD-ROMs. Instead of encoding data onto the CD-ROMs in a manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some...http://www.google.com/patents/US7539394?utm_source=gb-gplus-sharePatent US7539394 - Method and apparatus for the copy protection of optical discs
