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videodisc or videodisk, disk used with a special player and television to reproduce both pictures and sound. A videodisc player cannot record television programs off the air for later playback, unlike a videocassette recorder (VCR). Videodiscs, however, generally produce pictures that are clearer in detail and truer in color than those produced by VCR tapes, and they also offer better sound quality. Two quite different videodisc systems have been developed. One operates much like a record player, using a mechanical stylus that senses varying patterns of electrical capacitance imprinted in grooves on the disc surface. This format has largely fallen into disuse. The other, known as a laser disc system, uses a laser to read a track cut in a spiral pattern on the inside surface of the disc. On a laser disc, video is recorded as an analog signal and the soundtrack is either an analog or, in more recent versions, a digital signal.
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