METHOD AND DEVICE FOR GENERATING INFORMATION FOR COPY PREVENTION SIGNALS OF VIDEO PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide copy prevention signals by comparing the size of the color difference signal component of color video signals with a certain settable threshold value level for each scene of color video images and supplying the information of '1' and '0' to a flag bit depending on being larger or smaller. SOLUTION: Component-encoded color video signals are supplied to an information- for-copy-prevention-signal addition circuit 13 and a color difference signal detection circuit 10. The color difference signal detection circuit 10 detects the color difference signal component and supplies the information of color saturation to one of the inputs of a comparator circuit 11. The comparator circuit 11 compares it with the certain settable determined threshold value level added to the other input and outputs the result to an information-for-copy-prevention-signal generation circuit 12. The information-for-copy-prevention-signal generation circuit 12 outputs the information for the copy prevention signals to the information-for-copy-prevention-signal addition circuit 13 corresponding to the result. In this case, the information for the copy prevention signals is added to the color video signals and used for the control of the phase modulation of color burst signals when component signals are converted to composite signals.