A modified Colorstripe copy protection process utilizes a basic anti-copy
protection (ACP) signal that causes attenuation of a video signal, wherein, in
one embodiment, the process modifies (lowers) the level of a front porch portion
and adds an incorrect color signal (color burst) in the region of the sync tip.
When an illegal copy is made, a pre-blanked end of line portion causes a TV set
to trigger the color burst sample pulse ahead of time and cause the incorrect color
signal in the sync tip region to be sampled. Thus, since the sync tip region has
incorrect color phase or frequency, the resulting illegal copy will have enhanced
color distortions. In other embodiments, other portions of the horizontal blanking
interval are lowered in level and incorrect color bursts are added to a portion
or portions of the back porch and/or a portion of the front porch.
A further embodiment employs lowering a back porch portion above a sync tip level
near the beginning of a video line to form a pseudo sync/AGC pulse pair. The various
embodiments of the process may include an adaptable process, as well as several
alternative ACP signals for use in combination with the process.