The player will refuse to play discs that are not coded for its region. A disc bought in one country may not play on a player bought in another country.
Regional codes are entirely optional for the maker of a disc. Discs without region locks will play on any player in any country. It's not an encryption system, it's just one byte of information on the disc that the player checks.
Region codes are a permanent part of the disc, they won't "unlock" after a period of time. Region codes don't apply to DVD-Audio, DVD-ROM, or recordable DVD.
Seven regions (locales or zones) have been defined, and each one is assigned a number. Players and discs are often identified by their region number superimposed on a world globe. If a disc plays in more than one region it will have more than one number on the globe.
- U.S., Canada, U.S. territories
- Japan, Europe, South Africa, and Middle East (including Egypt)
- Southeast Asia and East Asia (including Hong Kong)
- Australia, New Zealand, Pacific Islands, Central America, Mexico, South America, and the Caribbean
- Eastern Europe (Former Soviet Union), Indian subcontinent, Africa, North Korea, and Mongolia
- Special international venues (airplanes, cruise ships, etc.)
Technically there is no such thing as a region zero disc or a region zero player.
There is such thing as an all-region disc. There are also all-region players.
Some players can be "hacked" using special command sequences from the remote control to switch regions or play all regions or can be physically modified ("chipped") to play discs regardless of the regional codes on the disc. This usually voids the warranty, but is not illegal in most countries (since the only thing that requires player manufacturers to region-code their players is the CSS license).
Many retailers, especially outside North America, sell players that have already been modified for multiple regions, or in some cases they simply provide instructions on how to access the "secret" region change features already built into the player. As an interesting side note, on Feb. 7, 2001, NASA sent two multiregion DVD players to the International Space Station.
Some discs from Fox, Buena Vista/Touchstone/Miramax, MGM/Universal, Polygram, and Columbia TriStar contain program code that checks for the proper region setting in the player.
In late 2000, Warner Bros. began using the same active region code checking that other studios had been using for over a year. They called it "region code enhancement" (RCE, also known as REA), and it received much publicity.
"Smart discs" with active region checking won't play on code-free players that are set for all regions (FFh), but they can be played on manual code-switchable players that allow you to use the remote control to change the player's region to match the disc. They may not work on auto-switching players that recognize and match the disc region.
Region codes don't apply to recordable DVDs. A DVD that you make on a PC with a DVD burner or in a home DVD video recorder will play in all regions. Region codes do not apply to DVD-Audio.
Regional codes apply to game consoles such as PlayStation 2 and Xbox, but only for DVD-Video (movie) discs. PlayStation has a separate regional lockout scheme for games. Regional codes also apply to DVD-ROM computers, but affect only DVD-Video discs, not DVD-ROM discs containing computer software. Computer playback systems check for regional codes before playing movies from a CSS-protected DVD-Video.
Newer RPC2 (stands for region protection control) DVD-ROM drives let you change the region code several times. Once an RPC2 drive has reached the limit of 5 changes it can't be changed again unless the vendor or manufacturer resets the drive.