OPTICAL DISK WITH COPY PROTECTION

摘要

Copy-protected optical disk format (512), optical disk recording apparatus for creating disks having such formats and optical disk reading apparatus for reading disks having such formats and for determining whether the disks are authentic (514). In one aspect, an authentic optical disk has data bit indications along a spiral centerline of the disk, and these data bit indications define a radial wobble which has substantially greater energy at a predefined frequency fcpw (such as fcc/392) than at a frequency of fcc/196, where fcc is the spatial channel clock frequency (538). In another aspect, an authorized optical disk has data bit indications along a substantially spiral centerline of the disk, according to a channel clock whose frequency varies across the disk (528). The disk further has stored thereon an indication of the number of such channel clock cycles which occur along a predetermined test segment of the centerline, optionally together with a pointer to the test segment (526).