System and method for controlling display of copy-never content

Abstract

A method and system for controlling the use of unauthorized content, and specifically for controlling the display of content that is marked as “copy-never.” A compliant signal source transmits a video signal along with a secure timestamp to a compliant display device. The compliant display device determines whether the video signal is authorized to be displayed by determining the content management usage rights status in the video signal and the delay between when the video signal was transmitted and when it was received. In an embodiment of the invention, copy-never content that exceeds a defined delay between transmission and reception is prevented from being displayed.

1 .- 36 . (canceled) 
     
     
         37 . A video display device, comprising:
 a detector adapted to detect a secure timestamp for a video signal received by the video display device;   a comparator operatively connected to the detector, and adapted to determine a transmission time lag being a difference between a time indicated by the secure timestamp and a time the video signal is first received by the display device; and   a display driver operatively connected to the detector and to the comparator, wherein the comparator and display driver are configured to prevent normal display of the video signal by the display device if the transmission time lag exceeds a defined maximum lag period, and to display the video signal as a video image on the display device if the transmission time lag does not exceed the maximum lag period.   
     
     
         38 . The video display device of  claim 37 , wherein the detector is further adapted to determine whether a copy-never indicator is associated with the video signal. 
     
     
         39 . The video display device of  claim 38 , wherein the comparator and display driver are further configured to prevent normal display of the video signal only if the video signal comprises a copy-never indicator. 
     
     
         40 . The video display device of  claim 37 , wherein the comparator and display driver are further configured to prevent normal display of the video signal if the detector does not detect that the video signal comprises a secure timestamp. 
     
     
         41 . The video display device of  claim 37 , wherein the detector is further adapted to obtain a value of the secure timestamp from the video signal. 
     
     
         42 . The video display device of  claim 41 , wherein the detector is further adapted to obtain a value of the secure timestamp from a defined portion of a vertical blanking interval of the video signal. 
     
     
         43 . The video display device of  claim 41 , wherein the detector is further adapted to obtain a value of the secure timestamp from a watermark contained in the video signal. 
     
     
         44 . The video display device of  claim 37 , wherein the comparator and display driver are further configured to prevent normal display of the video signal if the transmission time lag exceeds a number in the range of about 1 to 1000 milliseconds. 
     
     
         45 . The video display device of  claim 37 , wherein the comparator and display driver are further configured to prevent normal display of the video signal if the time lag exceeds a number in the range of about 1 to 100 minutes. 
     
     
         46 . The video display device of  claim 37 , wherein the detector is further adapted to decrypt a value for the secure timestamp using public and private keys. 
     
     
         47 . A video display device operative to:
 process a video signal to detect a secure timestamp indicating a time when transmission of the video signal is initiated from a signal source to the at least one display device;   compare the secure timestamp with a time at which the video signal is first received by the display device;   prevent display of the video signal by the display device if a difference between the time the video signal is first received by the display device and the time indicated by the secure timestamp is greater than or equal to a defined maximum; and   display a video image supplied by the video signal if the difference is less than the defined maximum.   
     
     
         48 . The video display device of  claim 47 , further configured to detect whether a copy-never indicator is associated with the video signal. 
     
     
         49 . The video display device of  claim 48 , further configured to prevent display of the video signal if the copy-never indicator is detected and the difference between the time the video signal was received and the time indicated by the secure timestamp is less than or equal to a defined maximum. 
     
     
         50 . The video display device of  claim 47 , further configured to display the video signal if the detector fails to detect a secure timestamp associated with the video signal, regardless of the difference between the time the video signal was received and the time indicated by the secure timestamp. 
     
     
         51 . The video display device of  claim 47 , further configured to determine a value of the secure timestamp from a vertical blanking interval of the video signal. 
     
     
         51 . The video display device of  claim 47 , further configured to determine a value of the secure timestamp from a watermark in the video signal. 
     
     
         52 . The video display device of  claim 47 , further configured to prevent display of the video signal if the time difference exceeds a number in the range of about 1 to 1000 milliseconds. 
     
     
         53 . The video display device of  claim 47 , further configured to prevent display of the video signal if the time difference exceeds a number in the range of about 1 to 100 minutes. 
     
     
         54 . The video display device of  claim 47 , further configured to decrypt a value for the secure timestamp using public and private keys.