M (videocassette format)
（重定向自Recam）
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.