**ATRAC**(

**Adaptive TRansform Acoustic Coding**) is an audio compression algorithm used to store information on Minidiscs, developed by Sony. It uses quadrature mirror filters and modified discrete cosine transform to represent encoded audio.

Table of contents |

2 ATRAC LP 3 ATRAC-3 LP-2 4 ATRAC-3 LP-4 |

### ATRAC SP

Two stacked QMF split the signal into 3 parts:

No joint stereo encoding.Data rate is 266 Kb/s

### ATRAC LP

### ATRAC-3 LP-2

Three stacked QMF split the signal into 4 parts:

Joint stereo encoding. 132 kbit/s (yes, 15% below ATRAC SP/2)