(ATRAC) An audio compression algorithm, introduced bYSonY for its Mini 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. [Does SonY Minidisk use ADPCM?] (2001-12-13)