Video transmission method, video copy protection method and apparatus

摘要

A playback device generates a PN code sequence which repeatedly generates with a predetermined period video in synchronism with a video sync signal. An anti-duplication control signal is spectrally spread using this generated PN code sequence, superimposed on the video signal and output. A PN code sequence having the same timing and code pattern as the PN code sequence used in the playback device is similarly generated based on the video sync signal on the receiving side which receives the output video signal. using this PN code sequence, reverse spectral spread is performed, the anti-duplication control signal superimposed on the video signal is extracted, and anti-duplication control is performed according to the extracted anti-duplication control signal.