It almost makes us nostalgic for the 80s. With Digital Rights Management, it’s easier to put limits on almost anything - coffee makers, arcade games, and even kitty litter all sport copy protection these days. They also messed with the vertical synchronization, and the effect was to make dubbed tapes unwatchable, even by 1985 standards.Ĭopy protection was pretty effective, and pretty clever given the constraints. Normally the VBI has signals that the VCR uses to set its recording levels, but Macrovision figured out that sending extra signals in the VBI fooled the VCR’s automatic gain controls into varying the brightness of the recorded scenes. It used the vertical blanking interval (VBI) in the analog signal, the time during which the electron beam returns to the top of the frame.
The idea for Macrovision copy protection was to leverage the difference between what a TV would accept as a valid analog signal and what the VCR could handle. Ironically, Macrovision the company later morphed into the TiVo Corporation. It was dubbed “Analog Protection System” or “Analog Copy Protection” by Macrovision, the company that developed it. If you’ve ever wondered how copy protection worked in pre-digital media, wonder no more. has done a nice primer on one of the main copy protection scheme from the VHS days. But then came The Man with all his “rules” and “laws” about not stealing, and suddenly tapes weren’t so easy to copy. Sure, the video quality degraded with each generation, but it was so bad to start out with that not paying $25 for a copy of “Ghostbusters” was a value proposition. Oh, for the old days when sailing the seas of piracy was as simple as hooking a couple of VCRs together with a dubbing cable.