The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 26, 2009
Filed:
Jan. 23, 2004
Philippe Marcel Henri Selve, Woodley, GB;
Victor Kovner, Woodley, GB;
Richard A. A. Heylen, Leeds, GB;
Philippe Marcel Henri Selve, Woodley, GB;
Victor Kovner, Woodley, GB;
Richard A. A. Heylen, Leeds, GB;
Macrovision Europe Limited, Berkshire, GB;
Abstract
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 of the recorded digital data unbalanced dc content. Thus, for example, the DSV value of the encoded data may be changed rapidly in less than (100) frames to (FIG.). For an area of digital data on the optical disc in which the DSV has been caused to rise steeply (FIG.), heavy distortions in audio arise (FIG.) during an attempt to copy an audio track including the single segment of unbalanced dc content.