NTSC and PAL refers to the frames per second used by televisions around the world. There are two television display systems in commercial use: PAL, which is common in UK, Europe and parts of Asia and delivers at a frame rate of 25 frames per second with 625 lines; NTSC is common in USA and Canada and delivers at a frame rate of 30 frames per second using 525 lines. Picture size and pixel aspect ratios also vary but the main thing to be aware of is that all DVD players sold in PAL countries can play both kinds of discs. Most NTSC players cannot play PAL discs.