From The TV IV
Home video formats like DVD and Blu-ray contains one or more region codes, denoting the area(s) of the world in which distribution and playback are intended. The commercial DVD and Blu-ray specifications dictate that a player must only play discs that contain its region code. In theory, this allows the motion picture studios to control the various aspects of a release (including content, date and price) on a region-by-region basis. In practice, many players allow playback of any disc, or can be modified to do so. Entirely independent of encryption, region coding pertains to regional lockout. To the right, you can see an image of what the region code indicator on back side of a DVD's outer packaging would look like for the six most common regions. Typically, you would see a sticker with just one of those numbers, indicating which region the DVD is supposed to be viewed in. Note that the Blu-ray regions are different, instead of 6 there are 3 and they are denoted by letters instead of numbers.
DVD Region Code Information
|Region Code||Location of Use|
|0||No Region Coding|
|1||United States of America, Canada|
|2||Europe, Greece, Turkey, Egypt, Arabia, Japan and South Africa|
|3||Korea, Thailand, Vietnam, Borneo and Indonesia|
|4||Australia and New Zealand, Mexico, the Caribbean, and South America|
|5||India, Africa, Russia and former USSR countries|
|6||Peoples Republic of China|
|9||Expansion (often used as region free)|
European Region 2 DVDs may be sub-coded "D1" through "D4." "D1" identifies a United Kingdom-only release. "D2" and "D3" identify European DVDs that are not sold in the UK and the Republic of Ireland. "D4" identifies DVDs that are distributed throughout Europe.
Any combination of regions can be applied to a single disc. For example, a DVD designated Region 2/4 is suitable for playback in Western Europe, Oceania and any other Region 2 or Region 4 area. A so-called "Region 0" disc (actually coded Region 1/2/3/4/5/6) is meant to be playable worldwide.
Multi-Region DVD players
The term "Region 0" also describes DVD players that were designed or modified to incorporate Regions 1-6 simultaneously, thereby providing compatibility with virtually any disc, irrespective of region. This apparent solution was popular in the early days of the DVD format, but studios quickly responded by adjusting discs to refuse to play in such machines. This system is known as "Regional Coding Enhancement" or RCE.
Nowadays, many "multi-region" DVD players defeat 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.
Many people view region code enforcement as a violation of WTO free trade agreements; however, no legal rulings have yet been made in this area.
Blu-ray Region Code Information
|Region Code||Location of Use|
|(No code)||No Region Coding|
|A||North America, South America, East Asia (except China and Mongolia), Southeast Asia|
|B||Africa, Southwest Asia, Europe (except Russia), Australia|
|C||Central Asia, China, Mongolia, South Asia, Russia|