A 5" plastic disk that looks like a compact disk, using the same concept of microscopic pits arranged in a spiral and read using a laser. Except for double sided DVD's (CD's come only single sided) the only way to tell the difference is to look at the label or markings engraved near the center. Today's DVD's can play a movie with more resolution than 12 inch laser disks and just over four hours in length without the need to stop the player and turn the disk over. Double sided DVD's can have a "
pan and scan" version of a movie on one side and a wide screen version on the other. Or programs can be recorded with different camera angles you can choose from. The present NTSC DVD picture is usually 704 or 720 (occasionally 640) pixels across by 480 pixels high compared with LD's up to 565 details across (425 lines) and approx. 480 scan lines high. Using S-Video (Y/C) or component video inputs, DVD has much better color horizontal resolution, up to 270 lines for all colors versus LD's 40 to 120 lines for different colors. As of May 1998 no consumer products are available to record one's own DVD's but the promise is there for the future. A CD player cannot play a DVD; most DVD players can play CD's. For computer use, the nominal capacity of a DVD is 4.7 gigabytes per layer; there may be one or two layers per side, and disks may be double sided.
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