Adaptive Transform Acoustic Coding

Description
Adaptive Transform Acoustic Coding (ATRAC) is a family of proprietary audio compression algorithms created by Sony. It was designed to meet the need for the MiniDisc format to maintain high sound quality and a 74 minute playing time, despite having considerably less storage space than an Audio CD.

A number of improved versions of ATRAC have been released since 1992 - ATRAC3 (1999), ATRAC3plus (2002), ATRAC Advanced Lossless (2006).

Per this Washington Post article, Sony has largely dropped support for ATRAC, although it is not clear to what extent. The PlayStation 3 supports playback of ATRAC3plus and ATRAC Advanced Lossless files, and the Wikipedia article suggests that some support remains in Japan.

Information

 * ATRAC: Adaptive Transform Acoustic Coding for MiniDisc - a description of the psychoacoustic principles, encoder and decoder for the original ATRAC format
 * Source for FFmpeg's ATRAC1 compatible decoder
 * Source for FFmpeg's ATRAC3 compatible decoder
 * Source for FFmpeg's ATRAC3plus compatible decoder

Software

 * FFmpeg has decoders for ATRAC, ATRAC3 and ATRAC3plus
 * A suite of tools for converting ATRAC to MP3
 * SonicStage v4.3, which supports ATRAC3 / 3plus and ATRAC Advanced Lossless

Links

 * PlayStation Knowledge Centre - Enable PS3 ATRAC Audio Playback
 * Faster Forward - Sony Connect, ATRAC Exit the Stage
 * Techdirt - Sony Finally (Really) Dumps Proprietary ATRAC Format No One Wanted For Its Walkmen
 * Sony Global - ATRAC3 product page