Improvements in or relating to the copy protection of optical discs

摘要

Subversive data has been incorporated in the content of an optical disc, such as a DVD, to prevent copying of the disc. To defeat such copy protection, devices to copy optical discs are now being controlled to only copy data referred to by selected program paths. Accordingly, it is proposed to provide copy protection for optical discs by introducing errors into redundant control data to frustrate access to content on the disc. For example, the errors may be inconsistencies in a Video Manager Information Table (VMGI) or in a Video Title Set Information Table (VTSI).