Patent ID: 8526794
Filing Date: 2013-09-03
Classification: H04N

Abstract:
1. A method of improving playability of a copy protected video signal by reducing venetian blind darkening effects in the video signal, wherein a copy protection signal includes automatic gain control (AGC) pulses in video lines in a portion of an active or viewable television field or frame, comprising: inserting or adding non similar AGC pulses from one video line to another video line, in a back porch region of the video lines in the active or viewable television field or frame, wherein the non similar AGC pulses are positive going pulses whose amplitudes are greater than zero IRE and change in IRE from one video line to a next video line; and wherein the inserting or adding improves playability in a television set by reducing venetian blind darkening effects when compared with adding back porch AGC pulses in 1/N lines or one our of every N lines in the active television field.