The MiniDisc (MD) is a magneto-optical disc-based data storage device for 74 minutes and, later, 80 minutes, of digitized audio or 1 gigabyte of Hi-MD data. The Sony brand audio players were on the market from September 1992 until March 2013.MiniDisc was announced by Sony in September 1992 and released that November for sale in Japan and in December in Europe, Canada, the USA and other countries .