Method and apparatus for digitally removing or defeating effects of copy protection signals from a video signal

摘要

Video signals in today's environment exist in both the analog domain and the digital domain. In many instances it may be desirable to delete or reduce the effectiveness of a video signal containing analog copy protection signals while the signals are in the digital domain. The invention uses digital techniques for defeating the effects of the analog copy protected signal while the signal is in the digital domain. The types of copy protection signals includes pseudo sync pulses and AGC pulses. Additionally digital techniques may be used for reducing or eliminating the affects of a chroma copy protection process. A digital video copy protection eliminator allows removal of substantially all pseudo sync pulses and/or AGC pulses in the digital domain. The location of pseudo syncs and/or AGC pulses are determined, while the signal is in the digital domain. These known pixel locations of all or some of the pseudo syncs and/or AGC pulses are used to digitally modify the signal so as to effectively remove the pseudo sync pulses and/or AGC pulses. Digital methods can also be applied to effectively eliminate or correct the chroma (burst phase modulation) protection process and or enhanced video copy protection signals in the digital domain.