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:
Apr. 16, 2002
Filed:
Jan. 06, 1998
Mark D. Conover, Cupertino, CA (US);
Fleming M. Oliver, Sunnyvale, CA (US);
Pixel Tools Corporation, Cupertino, CA (US);
Abstract
A for method watermarking a compressed video bitstream selects for modification numerous sites within an MPEG compressed video bitstream, each of which sites includes a DCT coefficient which is apt for modification. Watermarking sites are preferably located in MPEG B frames, and the DCT coefficient to be modified preferably has a run-length of zero (0). The method then embeds the watermark by modifying the DCT coefficient for at least some of the selected sites. A list specifying the watermarking sites may be transmitted together with the compressed video bitstream to permit further watermarking by subsequent bitstream receivers. A system for detecting an unauthorized copy of a watermarked video forms a synchronized, frame-by-frame difference between a possibly unauthorized copy of the watermarked compressed video and an un-watermarked copy of the video. Data in the watermarking site list permits readily locating watermarks within the possibly unauthorized copy.