Audio and video processing method with copy protection

摘要

The method involves dividing the audio and video data into a number of sample blocks. Each block of samples is subject to a time or frequency transformation to determine the spectral energy of the block. The transformed spectrum is processed to eliminate spectral lines according to predetermined psycho-sensorial criteria. Bits are allocated to the lines which have not been eliminated. Certain spectral lines are replaced by marking codes which are chosen so they are masked according to psycho-sensorial criteria. The spectral lines chosen for marking are determined according to a predetermined algorithm which is based on a secret pseudo-random sequence.