Adaptive Transform Acoustic Coding
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.
- 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
- 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