DVDs have the ability to encode an option which specifies which regions in the world the discs can be played. The movie studios have collectively divided the planet into zones which corresponds to their distribution system. In theory, this allows the motion picture studios to control the various aspects of a release, including content, date and price region-by-region. In practice, many DVD players allow playback of any disc, or can be modified to do so.

Special Regions:
Region 0: region free" or "all regions"
Region 7: Reserved for future use
Region 8: International venues such as aircraft, cruise ships

There are six regions, with two additional regions reserved for specialized use. Technically there is no region 0 code; instead every region code flag is set, making the disc playable worldwide.

One more thing to take note of is that not all discs of the same file and with the same region are created equally and with the same features. For example region one discs, intended for release in the United States, are often not the same as those intended for release in Canada. Discs may vary in extra content and even movie titles. English movie titles from Japan often have a different name when released in the United States. When buying discs from the same region but from different countries it is also recommended to check the video format (PAL/NTSC). Region 2 discs intended for Japan are often not the same as those released in the UK. So, when you buy a DVD you must check the region code, the video format and the disc content (for example: extras).

One new aspect of region coding is Region Code Enhancement (RCE). This is designed by the studios to prevent viewing a Region 1 disc on a Region Free DVD player, however, it does not prevent watching the movie on a MultiRegion Player. Currently not all movie studios use RCE. Warner Bros, New Line, Columbia and some MGM discs make use of this feature.

RCE did cause a few problems with genuine region 1 players. Recently many "multi-region" DVD players get around regional lockout and RCE by automatically identifying and matching a disc's region code and/or allowing the user to manually select a particular region. Others simply bypass the region code check entirely. Some manufacturers of DVD players now freely supply information on how to disable regional lockout, and on some recent models, it appears to be disabled by default.