A video system anti-copying device in which leading and trailing code sequences are inserted into the luminance portion of a video signal. These code sequences are visually manifested as dropouts on a video monitor. When the sequences match, operation of record circuitry in a video recorder is inhib...http://www.google.de/patents/US5134496?utm_source=gb-gplus-sharePatent US5134496 - Bilateral anti-copying device for video systems
