Patent Number: 7,085,380

Title: Method for modifying a copy protected video signal with a negative amplitude pulse

Abstract: An enhancement is provided for a copy protection method that discourages copying (e.g., by video taping) of video signals. The enhancement adds negative amplitude pulses to the video signal at a location in the horizontal blanking interval "back porch" after the color burst. This enhances jitter when the copy protected signal is recorded on a VCR (video cassette recorder) and the recording is replayed, thereby making the recorded signal not suitable for viewing.

Inventors: Quan; Ronald (Cupertino, CA)

Assignee: Macrovision Corporation

International Classification: H04N 7/167 (20060101)

Expiration Date: 8/01/02018