Video signal

Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media.

Video systems vary greatly in the resolution of the display and refresh rate. Video can be carried on a variety of media, including radio broadcast, tapes, DVDs, computer files etc.

Video technology was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) television systems, but several new technologies for video display devices have since been invented. Video was originally exclusively a live technology. Charles Ginsburg led an Ampex research team developing one of the first practical video tape recorder (VTR). In 1951 the first video tape recorder captured live images from television cameras by converting the camera's electrical impulses and saving the information onto magnetic video tape.

Video recorders were sold for $50,000 in 1956, and videotapes cost $300 per one-hour reel. However, prices gradually dropped over the years; in 1971, Sony began selling videocassette recorder (VCR) decks and tapes into the consumer market.

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