| 摘要 |
A method and apparatus for inserting source identification data into a video signal prior to its transmission, recording or display. The source identification data (Finger Print) is injected into the active picture area of a video signal without disturbing the viewing of the video signal and the data is retrieved by a data reader, called a Fingerprint Reader. The data injection or "fingerprinting" process consists of dynamically offsetting the video pedestal to carry information which can then be read back from any videotape made from the output of the data-injecting unit. In particular, the fingerprint carries the ID number of the unit used and the current date. The offset lasts for one entire field and has an amplitude of approximately 0.5 IRE- that is, a given field either has the nominal setup or a setup value differing from nominal by 0.5 IRE. The data is repeated every 128 fields in order to provide ample samples for the reader to detect and display the source identification data.
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