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:
Jul. 18, 2000
Filed:
Jan. 08, 1998
Andrew B Mellows, Palo Alto, CA (US);
John O Ryan, Cupertino, CA (US);
William J Wrobleski, Sunnyvale, CA (US);
Ronald Quan, Cupertino, CA (US);
Gerow D Brill, Mountain View, CA (US);
Macrovision Corporation, Sunnyvale, CA (US);
Abstract
A technique is disclosed for preventing unauthorized playback of scrambled video/audio signals recorded on, for example, a video tape cassette, which technique includes several cooperating processes and apparatus which further prevent the playback of recorded video/audio when the playback apparatus is in a still or pause mode of operation. The technique includes selected combinations of processes of inverting and re-clamping the luminance component of the video signal just prior to FM modulation; blanking an overscan portion, or portions, of the video signal and adding a video retrace signal to the overscan portion(s); inverting the normal control track signal and position modulating the normally unused edge; and selectively scrambling the audio signal and recording the scrambled audio signal in an audio track or in a Hi-Fi track. A selected user specific authorization code is recording in and recovered from the audio track. The recorded scrambled video/audio signal is recovered via a modified combo VCR/TV unit with no external video/audio jacks, which reverses the scrambling processes mentioned above, but only if the descrambling apparatus is authorized by having the proper recovered authorization code.