DVD region codes were developed by motion picture studios so they can control the home release of movies in different countries. A movie may come out on video in the United States when it is just being released in European theaters.
Every DVD player is given a code for the region that it is sold. A DVD player will not play a disc that is not coded for its region. This means that a DVD purchased in one country may not play on a DVD player purchased in another country.
Sony® DVD players sold in the U.S. are coded to play Region 1 DVDs. They also will play discs labelled Region 0 or All. There is no way to override the region code.
NOTE: Region codes do not apply to recordable DVDs.