US Patent 7398008 Copy protection for analog video signals from computing devices

A copy protection method and apparatus is provided to inhibit unauthorized viewing or copying of a video signal. A varying set of additional or invalid video pulses are generated onto a typical video signal. A pulse sequence identifier identifies the location of the invalid or additional pulses and is likewise generated onto the video signal prior to the occurrence of the identified pulses. The combined signal is received at an authorized display which then decodes or filters the additional or invalid portion of the video signal from the original signal according to a decode protocol stored in local memory. A resultant video output signal is guaranteed from only the original signal.