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From: u546025938ea@vega.ucdavis.edu (0040;0000003281;0;340;141;)
Newsgroups: sci.electronics,rec.audio
Subject: Re: TV distortion from copy protected video tapes?
Summary: Not a solution, but an explanation
Keywords: TV,video,copy protection
Message-ID: <3694@ucdavis.ucdavis.edu>
Date: 18 Feb 89 00:31:15 GMT
References: <1502@mhuxo.UUCP>
Sender: uucp@ucdavis.ucdavis.edu
Reply-To: u546025938ea@vega.ucdavis.edu (Steve Meyer)
Distribution: na
Organization: University of California, Davis
Lines: 29

In article <1502@mhuxo.UUCP> ajb@mhuxo.UUCP (Andrew Becker) writes:
>
>     I have noticed that some commercially produced video tapes produce
>a distorted picture and sound track when played on my moderately old
>television set; I have no such problem with videos I have taped myself.
This might not be an explanation of your problem, but I'll give it a shot:

Many new videocassettes on the rental market are employing a form of
copy protection.  One of the popular methods involves playing with the
level of the video signal.  The protection scheme makes the output level
seem to be higher than it actually is, causing the video load (i.e. your
television, second VCR, etc.) to reduce the video gain via the automatic
gain control.  This results in a low-level picture.  A cassette with this
protection is supposed to play properly when the VCR is connected directly
to the television, but it is recommended that there be no other devices
between the VCR and TV.

What might be happening is that the gain control on your (older) television is
getting confused, and setting an improper level.

I'm not very familiar with methods of copy-protection, but this is my
$0.02     :-)

Hope this helped........

Steve Meyer

Instructional Television              and     Student
Univerisity of California, Davis              UC Davis