(
Adaptive
TRansform
Acoustic
Coding
3) An early audio compression technology from Sony that provided multiple compression ratios. At 132 Kbps, the music could be compressed to about 10% of the space used by a CD. Introduced on the MiniDisc in 1993, the original ATRAC format provided near CD quality sound, but ATRAC3 rivaled the CD in 1999. ATRAC compression is 5:1; ATRAC3 is 10:1.
ATRAC3plus
In 2002, ATRAC3plus used a 20:1 compression ratio, bringing the data down to 5% of the original CD. It could achieve high quality sound at 48 and 64 Kbps or be indistinguishable from the original at 256 Kbps. See
Sony Memory Stick and
OpenMG.
ATRAC Advanced Lossless
ATRAC Advanced Lossless added correction data to the compressed file, which playback machines could use to make the audio lossless.
ATRAC9
Introduced in 2012 in the U.S., ATRAC9 was the last ATRAC lossy method. Designed for video gaming, it was used in Sony PlayStations.