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:
Sep. 04, 2001
Filed:
Jun. 08, 1998
Robert W. Schumann, Oakton, VA (US);
Siu-Leong Iu, Falls Church, VA (US);
Kobad Bugwadia, Sterling, VA (US);
Guillaume Mercier, Sterling, VA (US);
Shiva Ramadoss, Sterling, VA (US);
Michael Bergeron, Glen Allen, VA (US);
Jack Ehrhardt, Richmond, VA (US);
Digital Video Express, L.P., Herndon, VA (US);
Abstract
To enable the source of an unauthorized copy of an information-bearing medium, such as a video DVD, to be traced, a compressed digital signal stream to be stored on the medium is altered to include “running marks,” that comprise pixel blocks changing in position frame by frame and encoded with information designating where and when the copy was made. The medium under test is played back synchronously with a reference medium containing the locations of the running marks together with original video. The source of copying message is advantageously encrypted and scrambled to avoid detection or alteration by a copyist. The message preferably is spread, for example into a spread spectrum carrier, to enhance discrimination among a large number of sources and enable demodulation in the presence of noise.