due to the regional differences of the PAL (SECAM was also used in the early 1990s) and NTSC TV standards, but there is also a concern of copyright protection through regional lockout built into the video game systems and games themselves, as the same product can be released by different publishers on different continents. Notes See also ATSC Standards BTSC NTSC NTSC-J NTSC-US PAL PAL/E SECAM Video formats Video game development Digital rights management Hardware restrictions