In a rather futile twist to the norm, Macrovision the company that licences their WinMX flooding technology to the Cartel have today announced that they intend to pick on a few small fry, probably in a "water testing" exercise.http://www.slyck.com/news.php?story=829
Macrovision has developed a suite of copy protection tools, aimed at upgrading the dinosaur technology currently associated with DVDs. Towards this end, Macrovision has developed two DVD copy protection technologies, RipGuard DVD and ACP (Analog Content Protection.)
ACP is a copy protection technology designed to plug the dreaded "analog hole." ACP clandestinely scrambles the audio and video output, making poor quality analog duplication
Using the provisions of the DMCA legislation they aim to bring a sledgehammer down on a very tiny market ,well done Macrovision :roll: , in this case we need not sit idlely by and watch, for the budding engineers out there you too can defeat this puny protection method that is employed on the output of many dvd players.
Remember folks that you cannot legally build a box in some contries for this purpose but some of you may find your home movies can be smartened up if they are a bit over exposed.
The sytem employed does a very simple trick, as you watch the film it plays back ok but if you attempt to copy it you will find the brightness and colour varying randomly, how is this done ?
Well for those who dont know the recorder likes to check the electrical level of black in the picture so it can reference all the other scenes to that level , and what the nice folks at Macrovision provide is a simple way of inserting white blocks at the start of many of the first few lines of the video, this has the effect of messing up the reference level and the picture with it . (if you made the top of the picture smaller on your tv you could see this appear at the top )
The simple way to defeat it is to use a black level clamp and a switch IC , the switch is triggered by a simple line filter so that only the field/frame pulses get through to trigger a monostable, this switches the switch for a small (presettable) time to reclamp the black level of the video before continuing on to allow the normal video to pass through unmolested, this operation is repeated every frame, thus you have removed the protection with $5 worth of small easy to purchase components, If anyone is interested I will post a set of plans to construct your own "Video Clamping Aid" purely for your own use of course.