How does Macrovision copy protection work?
In the case of, say, a television broadcast, the author of the broadcast includes a code (called “setting bits”) which the receiving equipment detects. The receiving equipment (e.g. a Sky Digibox) contains a special I.C. which turns the Macrovision system on when the code is detected. One form of protection is simply to insert a large pulse into every picture “frame”. This has the effect of confusing a modern video recorder so that it thinks the contrast level is too high, and turns it down. The effect is to make the recorded picture alternate between light and dark, often with loss of synchronisation, causing the picture to “roll”. Of course the pulses have no effect on most TV sets (but see below).* Can it be defeated? Yes. Obviously the simplest way is to use an old fashioned video recorder that does not react to the pulses so the recording is unaffected. I haven’t tried it myself so I can’t tell you what makes or models might work. However, you’ll probably have trouble in finding s
