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M is the name of a professional analog recording videocassette format developed around 1982 by Matsushita and RCA. It was developed as a competitor to Sony's Betacam format. In the same way Betacam was designed to take advantage of cheap and readily available Betamax videocassettes, M used the same videocassette (and the same oxide-formulated magnetic tape loaded in the cassette) as VHS. M-Format also used a similar ''component video'' format to that used by Betacam, (as opposed to VHS's ''composite video'' format), and recorded at a much faster linear tape speed, as Betacam did. A cassette that would yield 120 minutes on a VHS VCR at SP speed would only yield 20 minutes on a M VCR. The format was called "M" due to the shape of the threading path of the tape around the helical scan video head drum, which resembles a letter M. (This is also how the U-matic format got its name, for its U-shaped tape path in the VCR.) VHS also uses the same M-shaped tape threading path as M; it was carried over to M from VHS. M had a similar 4-head recording system to Betacam, but the chrominance signals were recorded as two FM subcarriers of the main chrominance track FM carrier. M had little success in the professional/industrial video production market. This might have been due to RCA's Broadcast Products division, which marketed the M format in the United States under the "Hawkeye" brand name, going out of business in 1984 (shortly after M was introduced). Thus NBC was one of the few Broadcasters to use the format. Weak marketing by Matsushita for M might have been a factor as well. M was also marketed by Panasonic (a division of Matsushita) and Ampex under the Recam (REcording CAMera) name. M was succeeded in 1986 by the MII format developed by Panasonic, using a similar-sized cassette with completely different signal processing and a metal-particle tape formulation. ==See also== * MII (videocassette format) * Videotape format war 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「M (videocassette format)」の詳細全文を読む スポンサード リンク
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