Macrovision is a company that sells copy protection products.
The company's first product was a copy protection system for VHS tapes, which was also known as Macrovision. For a detailed look at that system, read Antti Paarlahti's Macrovision FAQ.
The Macrovision copy protection system was later extended to DVDs. Macrovision is designed to prevent DVDs from being copied to tape.
How Macrovision Works
Macrovision works by making modifications to the video signal, including:
- Automatic Gain Control: Macrovision inserts pulses into the vertical blanking signal. This confuses the synchronization and automatic-recording-level circuitry in most VCRs.
- Colorstripe: Macrovision creates a rapidly modulated colorburst signal.
Macrovision's Colorstripe mode can be defeated simply by using Component Output, which does not support burst.
Macrovision's AGC mode can be defeated with a number of off-the-shelf devices that regenerate a proper video blanking signal.
In addition, some DVD players do not enable Macrovision and others can be modified to turn off Macrovision.