Is DVD-Video a worldwide standard? What about NTSC, PAL, and SECAM?
DVD has the same NTSC vs. PAL problem as videotape and laserdisc. The MPEG video on DVD is stored in digital format, but it’s formatted for one of two mutually incompatible television systems: 525/60 (NTSC) or 625/50 (PAL/SECAM). There are three differences between discs intended for playback on different systems: picture size and pixel aspect ratio (720×480 vs. 720×576), display frame rate (29.97 vs. 25), and surround audio (Dolby Digital vs. MPEG). Video from film is usually stored 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%, so the audio must be adjusted accordingly before being encoded. Unless the audio is digitally processed to shift the pitch back to normal, it will be slightly high. All PAL DVD players can play Dolby Digital audio tracks, but no NTSC players can play MPEG audio tracks. PAL and SECAM share the same scanning format, so discs are the same for both systems.
