videotape recorder

Device for recording pictures and sound on cassettes or spools of magnetic tape. The first commercial VTR was launched in 1956 for the television broadcasting industry, but from the late 1970s cheaper models developed for home use, to record broadcast programmes for future viewing and to view rented or owned video cassettes of commercial films.

Video recording works in the same way as audio tape recording: the picture information is stored as a line of varying magnetism, or track, on a plastic tape covered with magnetic material. The main difficulty - the huge amount of information needed to reproduce a picture - is overcome by arranging the video track diagonally across the tape. During recording, the tape is wrapped around a drum in a spiral fashion. The recording head rotates inside the drum. The combination of the forward motion of the tape and the rotation of the head produces a diagonal track. The audio signal accompanying the video signal is recorded as a separate track along the edge of the tape.

Two video cassette systems were introduced to the mass market by Japanese firms in the 1970s. The Sony Betamax was technically superior, but Matsushita's VHS had larger marketing resources behind it and after some years became the sole system on the market. Super-VHS is an improved version of the VHS system, launched in 1989, with higher picture definition and colour quality.