Macrovision protection in VHS and DVD is also known as Copyguard and Analog Protection System.
Macrovision is named after the company that created the copy protection system.
Macrovision was first introduced in 1984 on VHS tapes. It was later added to DVD players to discourage copying of DVDs to VHS tapes.
Macrovision Doesn’t Prevent Copying
You can copy a Macrovision-protected tape or DVD through a VCR or a DVD recorder. However, the resulting copy will be garbled or ‘messed up’. That’s what the function if Macrovision is. It’s not to block copying. It allows copying but ‘spoils’ the copy made.
The Macrovision tape sends a kind of signal that the copying VCR or DVD recorder can’t handle.
The signal interferes with the working of the automatic gain control (AGC) of the recording machine resulting in inaccurate recording of the source content.
The recorded video is garbled or you’ll see a black screen then a bright screen when you play back the video. The whole idea is to interfere with your enjoyment of the recorded video content.
You can hear the audio clearly though.
Macrovision protection in VHS and DVD doesn’t interefere if you play the tape or disc directly to your TV. This is because most TVs don’t come with AGC.
Macrovision protection in VHS and DVD isn’t uncrackable. There are ways to disable it, mostly known to the tech-savvy.
Some DVD players have a ‘secret’ remote control code that can disable Macrovision.
There are also boxes that corrects the ‘false signal’ that Macrovision sends to the recording device.
Macrovision and HD Video
Macrovision protection in VHS and DVD is irrelevant in these days of HD video world where DRM and HDCP are employed to prevent unauthorised copying of copyrighted video content.
Macrovision is still available in DVD players but is of little significance. Nobody would think of copying a DVD to VHS these days.
Here’s a video that shows how Macrovision garbles a copied VHS.