The three differences between NTSC discs and PAL discs are:
1) Picture size and pixel aspect ratio (720x480 vs 720x576), 
2) Display frame rate (30 vs 25), 
3) Video from film is usually encoded at 24 frames/sec. but is preformatted for one of the two display rates. Movies formatted for PAL display are usually sped up by 4% at playback, so the audio must be adjusted accordingly before being encoded.