MII (pronounced as M 2) was an analogue videocassette format introduced by Panasonic in 1986 for professional use, to compete with Sony’s Betacam SP format.
MII was a development of the M format, which was originally derived from VHS, and it used ½ inch wide metal-formulated tape and component video recording.
Two sizes of MII cassette were available. The larger one was similar to a VHS cassette in size and had either a 60 or 90 minute recording time, and the smaller version provided 20 minutes.
MII had more success in the marketplace than its predecessor M, but MII suffered from poor marketing and customer support, and the machines gained a reputation for being less robust than those for Betacam SP.
It was used by a few UK television companies until the early 1990s, including Thames Television and TV-am. It was also used by NBC and PBS in the US, but NBC dropped it in the early 1990s in favour of the digital Sony D2 format.
The tape used in MII cassettes is very thin, and if stored badly can become mouldy and hence prone to tearing.