Their is a standard format for each country, NTSC, PAL and SECAM - other countries I know no longer use these standards. If you play a PAL disc on a NTSC player you might get a video without audio or black and white.
But their is a player who can play both (NTSC or PAL) - a switch at the back or you can find it on your remote. Bad news is that players are lock to to specific region to fight piracy. Good news - some electronics technicians knows how to bypass this inconvenience.