Macrovision is a company that develops copy protection schemes for DVDs, VHS Tapes and Television Content.
The original Macrovision copy protection was used on VHS tapes to prevent consumers from connecting two VCR's together with RCA style cables and dubbing VHS tapes. Video Rental was the source for much video piracy. This type of Macrovision worked by abusing 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 bright white and black 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.
Since VCR unites are typically equipped with an AGC circuit, this prevent VHS copy from producing a desirable video replica. Televisions are not equipped with an AGC circuit so Macrovision did not impact direct viewing from VCR to Television set.
What is really lame is that now in the digital age purposely recognize Macrovision to produce the Macrovision effect or refuse to copy a video source containing Macrovision when there is actually no real purpose for an AGC circuit in a digital recorder. Video capture cards such as the ATI Video Wonder or ATI All in Wonder have went to extra lengths to make sure their hardware and/or software detects the Macrovision signal and thus refuse to record or encode the video source. This isn't even tricking an AGC, it is outright pandering by companies to DRM schemes that restrict our freedom.
Another good example of a company pandering to the industry that is taking away our freedom is the DVR market. The Captive Works CW-100R would otherwise be a nice, low cost consumer DVR except, although there is no actual use for an AGC circuit, purposely has means to detect Macrovision and block your ability to record the video source.
This is a restriction for consumers trying to make backups of their prized movie collection that they legally purchased. Aging VHS tapes can be copied digitally to preserve them, and DVD's backed up - except when Macrovision stopped the consumer from doing so.
Macrovision Signal Removal
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.
VHS to VHS or VHS to Digital
A Digital Video Stabilizer is a device that, not necessarily advertised as the manufactured purpose, can be used to remove the Macrovision signal so a video source can be dubbed.
- Digital Video Stabilizer Model 200
- Sima SCC Video Color Corrector
Video Capture to a PC
The PV-231 real-time VCD PCI video/audio capture card card does not detect Macrovision and will copy from any Macrovision polluted video source without compromising the signal quality. Unfortunately, the PV-231 real-time VCD PCI video/audio capture card is an antiquated, lower quality video capture device.
The ADS IDVD will also ignore Macrovision.