Abstract: A video signal is modified so that a television receiver will provide a normal color picture but a video tape recorder will detect the modification and prohibit the video signal from being recorded. The color burst phase of the video signal is modified so as to make inferior quality pictures in the event that the resulting modified video signal is recorded. A disabling circuit (22) associated with the recorder (20) detects the presence of the modified video signal. This detection is done by determining the presence of modified color burst phase signals in even a single television line of the video signal. A control signal (26) is produced when the modified color burst phase signal is detected, which disables the recorder (20). If no modified color burst phase signal is detected, the recorder (20) is enabled to allow an acceptable recording of the video signal.

Abstract: A method and apparatus for adaptively controlling the presence of copy protection signals in a video signal depends upon the scene content of the video signal during an upper portion of a display of the video signal. Thus, in the upper portion of the scenes, wherein picture information would be noticeably altered by a hooking process the copy protection process is deactivated or effectively reduced to eliminate or reduce the hooking or tearing effects. The adaptive control of the copy protection improves the playability performance of copy protected video signals on a very small minority of television receivers which display a small hooking or tearing characteristic in the upper portion of the display of the copy protected video signal.