Video copy protection process enhancement to introduce horizontal and vertical picture distortions

Abstract

Enhancements to a video anticopying process that causes an abnormally low amplitude video signal to be recorded on an illegal copy. The enhancements in one version introduce into the overscan portion of the television picture, just prior to the horizontal or vertical sync signals but in active video, a negative going waveform that appears to the television receiver or videotape recorder to be a sync signal, thereby causing an early horizontal or vertical retrace. One version provides (in the right overscan portion of the picture), a checker pattern of alternating gray and black areas which causes the TV set on which the illegal copy is played to horizontally retrace earlier than normal in selected lines with a consequential horizontal shift of the picture information on those lines. This substantially degrades picture viewability. In another version a gray pattern at the bottom overscan portion of the picture causes vertical picture instability. In another version selected horizontal sync signals are narrowed, causing irregular vertical retraces. Also provided is apparatus for removing or attenuating these enhancements from the video signal, to allow copying.

1 . A method of processing a video signal, comprising: 
 providing pseudo sync pulses in a portion of a vertical blanking interval of the video signal;    adding AGC pulses in a portion of a blanking interval in selected video scan lines; and    providing a narrowed horizontal sync pulse in selected video scan lines.    
     
     
         2 . A method of processing a video signal, comprising: 
 inserting a basic copy protection signal in selected lines of the video signal;    adding a waveform in one or more selected video scan lines;    wherein the waveform effectively level shifts at least a portion of the video signal or of selected video scan lines thereof.    
     
     
         3 . The method of  claim 2 , wherein the waveform is in the frequency range of 100 KHz to 5 MHz.  
     
     
         4 . The method of  claim 3 , wherein the basic copy protection signal includes pseudo sync pulses, pseudo sync and AGC pulse pairs, or AGC pulses.  
     
     
         5 . The method of  claim 4  further comprising providing narrowed horizontal sync pulses in the video signal.  
     
     
         6 . A method of processing a video signal, comprising: 
 inserting AGC pulses, pseudo sync pulses, or pseudo sync/AGC pulses in selected video scan lines;    providing a narrowed sync pulse in selected horizontal blanking intervals of the video signal;    adding, inserting or providing a series of pulses in a portion of the video signal;    wherein the series of pulses are sensed by a sync separator and wherein the positive peaks of the series of pulses are of a level below a blanking level of the video signal.    
     
     
         7 . A method of processing a video signal for level shifting at least a portion of a video signal, comprising: 
 inserting a waveform having a frequency in the range of 0.1 MHz to 5 MHz into an overscan portion of the video signal;    wherein the waveform effectively shifts the level of the video signal located in at least part of the overscan portion.    
     
     
         8 . The method of  claim 7 , wherein the portion of the video signal is in a portion of its vertical blanking interval.  
     
     
         9 . The method of  claim 8 , wherein the portion of the vertical blanking interval includes an interval within part of the vertical sync signal.  
     
     
         10 . The method of  claim 9 , wherein the portion of the video signal is at a level below a blanking level.  
     
     
         11 . The method of  claim 10 , wherein the inserting the waveform in the range of 0.1 MHz to 5 MHz renders the portion of the video signal that is below a blanking level ineffective or inoperative.  
     
     
         12 . The method of  claim 8 , wherein the portion of the video signal that includes the waveform is effectively level shifted or rendered inoperative when recorded or recorded and played by a video recorder.  
     
     
         13 . A method of processing a video signal comprising: 
 inserting at least one of the following in an overscan portion of the video signal;    AGC pulses, pseudo sync pulses, AGC and pseudo sync pulses, and narrowed horizontal sync pulses; and    inserting one or more of the following in the video signal: amplitude modulated pulses after color burst envelopes, a waveform signal, a plurality of pulses, or and a square-wave signal, whose frequency is in the range of 0.1 MHz and 5 MHz.    
     
     
         14 . The method of  claim 13 , wherein the AGC pulses cause a copy protection effect on a video recorder, or wherein the narrowed horizontal sync pulses or amplitude modulated pulses enhance the copy protection effect.  
     
     
         15 . A method of processing a video signal, comprising: 
 inserting AGC pulses in selected blanking intervals of the video signal;    inserting a checker signal including two voltage levels in the video signal;    wherein the checker signal displays a rectangular or square pattern when an overscan portion of the video signal is displayed, and wherein the AGC pulse and the checker signal comprise at least part of a copy protection signal.    
     
     
         16 . A method of providing a copy protection signal, comprising: 
 inserting AGC pulses in a portion of one or more vertical blanking intervals; and    narrowing one or more horizontal sync pulses by inserting a positive going pulse in a portion of one or more horizontal blanking intervals.    
     
     
         17 . The method of  claim 16 , wherein the positive going pulse is added or inserted during a portion of a normal horizontal sync interval.  
     
     
         18 . The method of  claim 16 , wherein the positive going pulse is added to an input video signal to provide one or more narrowed horizontal sync pulses.  
     
     
         19 . Method of providing a modified video signal that is at least part of a video copy protection signal, comprising: 
 adding a positive going pulse in a portion of horizontal blanking intervals in selected lines of an incoming video signal, wherein the added positive going pulses reduce the duration of selected horizontal sync pulses of the incoming video signal.    
     
     
         20 . The method of  claim 19 , wherein the modified video signal includes in a portion of the vertical blanking interval at least one negative going pulse followed by a positive going pulse.  
     
     
         21 . The method of  claim 19 , wherein the modified video signal includes one or more positive going AGC pulses in one or more blanking interval portions of the video signal.  
     
     
         22 . The method of  claim 19 , wherein the modified video signal that is at least part of a video copy protection signal provides an attenuation or AGC or copy protection effect on a video recorder.  
     
     
         23 . The method of  claim 19 , wherein the added positive going pulse level shifts a portion of the sync tip of one or more horizontal sync pulses, and wherein the level shift provides a voltage of a duration above the sync tip level.