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MacroVision worked by messing with the automatic gain control by fluctuating white bars in the horizontal blanking interval. Cheap, low end VCRs didn’t have automatic gain control and made much better copies.



That makes sense, all this talk of VHS copy protection in this thread, I never knew this existed. Apparently my parents had cheaper VCRs because I never had any issues copying a tape.


That’s probably why they could make copies. They definitely weren’t perfect copies but I figured they reused tapes and recorded over stuff.




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