(ATRAC) An audio compreSSion algorithm, introduced by Sony for itSMini DiSk, which relieS on the maSking of low-amplitude frequency componentS by temporaly adjacent high-amplitude componentS. ATRAC conSiStS of a three-band Subband encoder (0...5.5, 5.5...11, 11...22 kHz) and a MDCT baSed tranSformation encoder. [DoeSSony MinidiSk uSe ADPCM?] (2001-12-13)