Abstract: Subservive 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 Manage Information Table (VMGI) or in a Video Title Set Information Table (VTSI).

Abstract: Subservive 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 Manage Information Table (VMGI) or in a Video Title Set Information Table(VTSI).

Abstract: Generally the more effective is the copy protection provided on an optical disc, such as a DVD, the greater is the likelihood that the copy protection will adversely interfere with legitimate uses of the optical disc. It is therefore proposed to include at least one region of subversive data within the content in the data area of an optical disc, and then to prevent access to each such region of subversive data during normal playback of the disc. For a DVD, the subversive data may be incorporated within video objects and/or may be in gaps between files in the DVD_Video zone. It is arranged that there are no navigable paths to the regions of subversive data.