a NTSC DVD player can only play NTSC DVD.
a Pal DVD player can only play Pal DVD.
There are two different methods for picture decoding standards: Europe (R2) uses the PAL system; North America (R1) uses the NTSC system.
How are NTSC and PAL different?
Firstly, NTSC and PAL differ in the number of scan lines available in the vertical axis of the screen; NTSC has 480, PAL has 576.
Secondly, there is a slight variation between NTSC and PAL running speeds. Where conventional film runs at 24 frames per second (fps), a TV signal runs at 30 fps (60 fields) for NTSC, or 25 fps (50 fields) for PAL.
For a PAL display, the simple method when transferring film is to present the film frames at 25 a second instead of 24 (the 4% speedup as mentioned above) and speed up the image to be synchronous with the images. The speedup raises the pitch of available audio tracks by one half of one tone although it's debatable as to whether this is distinguishable by the human ear.
The solution for a NTSC display is to spread the 24 film frames across the 60 video fields by alternating the display of the first film frame for 2 video fields and the next film frame for 3 video fields. This process is referred to as 2-3 pulldown and, again, it's questionable whether this process is noticeable to the human eye.
Which will win the war of the DVD player format? NTSC or PAL?