I have this friend who, like me, recently had an old VCR go kaput. Trying to back up a DVD, she ran into an issue where the picture would keep fading in and out. Turns out that's the stock behavior of Macrovision's analog copy protection scheme, where the overscan, iirc, information from a DVD screws with a VCR's automatic gain control and makes it more difficult to copy DVDs.

Personally I find the skirmishes between pirates and, um, ship captains? humorous. As far as I can gather, this gain control jive was originally a "feature" for VCRs, but later became a requirement. Honestly I'm still not sure what benefit the feature gave pre-copy protection. Why wouldn't TVs have it to? Does automatic gain control fix the output of crappy analog tapes? And if so, why doesn't it fix, to a certain degree, the VHS tapes after they've been taped? That is, why don't VCRs misread the DVD player's overscan lines in a way TVs don't while taping, but then play those tapes which now appear to have gain control issues more clearly thanks to automatic gain control?

Anyhow, it took me a while to figure out by what means it became a requirement -- that is, was it just that VCR producers were the same as DVD producers so they had a vested interest to stop copying, or was there a clear legal motivation? Of course it's the latter.

U.S. Copyright Office - Copyright Law: Chapter 12:

(A) Effective 18 months after the date of the enactment of this chapter, no person shall manufacture, import, offer to the public, provide or otherwise traffic in any —

(i) VHS format analog video cassette recorder unless such recorder conforms to the automatic gain control copy control technology;
...


Interesting. Why does the government get such a hands-on say-so in format wars? Will they ever do the same for "digitized music", likely starting with mp3? Why don't DVD players have the same sort of legal requirements for playing non-native DVD Region encoded DVDs? We've got a portable DVD player that plays anything. This was a great discovery when someone thought they were being clever by giving us a DVD purchased in Europe. Still, the lack of consistency and, to me, the format-specific government requirements, are pretty interesting.