On this page ...
Some information about MacroVision ...
Video equipment, suitable for playback of rental video's,
most of the time are equiped with something nasty called "MacroVision".
On this page I'll try to give you information so you get the general
idea behind MacroVision.
Note: This article has been merged with DVD and Blu-Ray region codes at Tweaking4All.com.
What is Macrovision?
MacroVision is a video copy protection method for video
playback equipment. First used on VHS tapes, later adapted for DVD's,
VCD's and SVCD's. It is used for pre-recorded videomedia.
You can detect MacroVision, by simply trying to dubb a protected tape,
the video that goes through the recording VCR will get dark and then normal
again periodically. The picture may also become unstable.
Sometimes Macrovision signals resemble false synchronization,
and some TV-sets mistake them for the real synchronization failures. Also
colors may vanish from the top of the picture. It resembles very much
a mistracked video-tape.
Some TV-sets do not like Macrovision;
the top of the picture might be unstable all the time and the colors may
flicker. Specially projectors and large screen TV-sets show this effect.
If you have a TV that has an adjustement for picture height or vertical
hold, you can fiddle around with those. Macrovision signals can be seen
as very bright and very dark regions (vertical bars) near the top of the
Most modern DVD and VCR's have MacroVision.
How it works
Here is a simple explanation of how the method works.
MacroVision abuses the Auto Gain Control (AGC) features
of a video-recorder.
Normally the AGC is supposed to amplify weak signals
and dimm the too strong signals.
MacroVision now inserts some non-standard signals in
the non-visable area of the TV-picture.
The additional video information may make the AGC think
that a sound picture is way to bright or way to dark.
The AGC kicks in and adjusts the video output to what
it thinks should be. For example the picture get's to dark or to bright.
This tricks is repeated over and over again in a random
order. The AGC therefor generates a too dark, then again a too bright,
etc picture. Pretty annoying if you have to watch a movie that manifests
Note that the this effect only appears when the signal
is redirecty by the VCR ...
So why isn't this happening when I hookup the playback
device directly to my TV-set?
That's easy: most TV-sets do not have a AGC ! Those
that have an AGC, behave differently than the one in your VCR.
Some VCR's, like Sony 8mm video, are not affected by
MacroVision since the AGC is not similar to the ones required for MacroVision
to work. Older VCR's (much older!) are not affected either since they
do not always 100% match the specifications required for MacroVision.
Can I disable MacroVision?
Before we can give an answer to that question, you should
know that modern video equipment like DVD-players can be "patched"
to disable MacroVision. For example the Yamakawa
DVD player has a "secret" remote control code to disable
MacroVision. Other players either have a similar code too, or there are
hardware patches out there that do so. An example is the Macro-Vision
remover by Nezzle which you can build yourself.
Simply rerouting video signal from TV to VCR or using
aerial input/output does not do the trick, MacroVision is to well integrated
in the video-signal.
Basically there is no quick and dirty trick to disable
MacroVision, however there a boxes available that filter the video signal
so MacroVision will not work anymore. These boxes can be bought on the
Internet or at most electronics stores. Schematics to build such a box
can be found in a lot of electronic magazines (for example Elektor)
Note: the MacroVision disablers or stabalizers
for the US market (NTSC) are not suitable for the European market (PAL)
and vice versa!