| 摘要 |
A high definition television video content management and/or copy protection method and apparatus are achieved by modifying portions of one or more channels of an HDTV (high definition television) signal. These modifications are generally in the blanking intervals but can extend into the overscanned portions. In one version, the signal modification defines tags or trigger bits for a content control system. This modification may follow the HDTV tri-level sync (synchronization) pulses for example, and it may occur in at least one of the HDTV video channels. In another version, portions of the tri-level sync pulse are modified to cause a reference sensing circuit such an AGC system (in a receiving device such as a video recorder) to produce an erroneous output. Optionally, a signal may be added or inserted following the modified tri-level sync pulses. In another version, tri-level pseudo sync pulses are added in blanking or overscanned intervals. These tri-level pseudo sync pulses may be asymmetrical and may be followed by a signal. Further, any of the above modifications or signals or sync signals may be modulated (e.g., amplitude, position, pulse~width). Also provided are defeat methods and apparatus to reduce effects or to modify results of the modification processes.
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