Enhancements to a video anticopying process that causes an abnormally low
amplitude video signal to be recorded on an illegal copy. In one version,
positive going pulses are added to the video signal. The enhancements in
one version introduce into the overscan portion of the television
picture, just prior to the horizontal or vertical sync signals but in
active video, a negative going waveform that appears to the television
receiver or videotape recorder to be a sync signal, thereby causing an
early horizontal or vertical retrace. One version provides (in the right
overscan portion of the picture), a checker pattern of alternating gray
and black areas which causes the TV set on which the illegal copy is
played to horizontally retrace earlier than normal in selected lines with
a consequential horizontal shift of the picture information on those
lines. This substantially degrades picture viewability. In another
version a gray pattern at the bottom overscan portion of the picture
causes vertical picture instability. In another version selected
horizontal sync signals are narrowed, causing irregular vertical
retraces. Also provided is apparatus for removing or attenuating these
enhancements from the video signal, to allow copying.