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From: wapd@houxj.UUCP (Bill Dietrich)
Newsgroups: net.video
Subject: Re: Cotton Club Anti-Piracy
Message-ID: <500@houxj.UUCP>
Date: Fri, 3-May-85 10:29:58 EDT
Article-I.D.: houxj.500
Posted: Fri May  3 10:29:58 1985
Date-Received: Sat, 4-May-85 01:48:01 EDT
References: <6543@ucbvax.ARPA> <135@bocar.UUCP>, <474@panda.UUCP>
Organization: AT&T Bell Labs, Holmdel NJ
Lines: 54


Here are some excerpts from an article in the Asbury Park (NJ)
Press, Tues April 30, 1985.

"New Techniques Thwart Illegal Video Tape Dubbers", by Jonathan Takiff,
Knight-Ridder Newspapers.  Page C8.

...

Their illegally made dub will be virtually unviewable - marred by
over-saturated colors, excess graininess and wiggly lines across
the screen.

...

"The Cotton Club" is the first home video release to employ
a new anti-copying protection system developed by Macrovision
of San Jose, Calif.

...

Inventor John Ryan (formerly chief engineer of camera development
for Ampex)  ...

...

Unlike previous "copyguard" anti-piracy technologies applied to
tapes, Macrovision's copy-jinxing system does not effect [sic]
the normal viewing of a protected tape when it is fed directly
from a VCR to a TV set.

"Copyguard inadvertently caused the picture (from an authorized
tape) to roll on some televisions, as well as spoiling tape copies.
So there was a legitimate reason for people to make, sell and buy
"stabilizers" that corrected the (vertical synchronization)
problem," notes Ryan.

"Our system delivers 100 percent viewability by attacking a
weakness in the automatic gain control circuitry that's
particular just to VCR's."

...

[techniques are different for Beta and VHS because AGC circuitry
is different]

...

[technique can also be applied to laser and CED-format videodiscs]

...

					Bill Dietrich
					houxj!wapd