This page describes the evil parts of the DVDVideo specification.
Region coding is a way for distributors of DVD-Video discs to restrict which parts of the world those discs can be used. The world is divided into 6 regions, and all DVD players sold into those regions are supposed to have the corresponding region number built-in. When a DVD disc is inserted into a player, the player is supposed to refuse to play the disc unless its code matches that of the player, or the disc has region code 0 (compatible with all regions).
The rationale behind region coding is to allow the movie distributors to stagger the release of a movie throughout the regions of the world. Naturally, a movie from Hollywood is released first in the USA. Then, once the cinemas have milked the new release for all they're worth, the studios will offer the movie on DVD. But these region-1 DVDs will not play on players in other regions of the world, therefore there is no danger of exports of these discs cannibalizing profits from cinematic release of the movie in those other regions, hence the studios can take their time releasing the movie overseas.
This sounds very much like anticompetitive collusion between the movie studios and companies involved with making DVDs. And indeed it is starting to be investigated as an illegal business practice in some jurisdictions (such as by the ACCC in Australia, but there has been no news of prosecutions yet.
Macrovision is a technique for committing unholy fiddles on an analog video signal in a way that doesn't affect TVs trying to show the picture, but does confuse video recorders trying to make a copy of it.
The circuitry for committing acts of Macrovision is built into all DVD players. It can be enabled by setting a bit in the .VOB file. However, before setting this bit, you have to pay a licence fee to Macrovision Corp. And the makers of DVD players have to pay a fee to Macrovision Corp. And the makers of the actual integrated circuits built into those DVD players that implement the Macrovision function have to pay a fee to Macrovision Corp. How's that for triple-dipping?