MiniDisc (MD) is an erasable magneto-optical disc-based data storage format offering a capacity of 60, 74, and later, 80 minutes of digitized audio. Sony announced the MiniDisc in September 1992 and released it in November of that year for sale in Japan and in December in Europe, North America, and other countries. The music format was based on ATRAC audio data compression, Sony's own proprietary compression code. Its successor, Hi-MD, would later introduce the option of linear PCM digital recording to meet audio quality comparable to that of a compact disc. MiniDiscs were very popular in Japan and found moderate success in Europe; although it was designed to be the successor of the cassette tape, it did not manage to mass replace it globally.