ATRAC3

From PSPWiki

'ATRAC™ (Adaptive TRansform Acoustic Coding) is a proprietary Sony audio compression format that was originally created for Minidisc use. It is somewhat of a substandard audio format despite consideration of its compression. It has two modes, the standard came in last place in a double-blind study against OGG Vorbis, AAC, and MP3. The second mode has quality roughly equivelant to a cassette tape.

ATRAC3plus™ is a higher quality version based on the codec, created for HiMD players and high quality audio from a Memory Stick. Sony's own testing revealed ATRAC3plus™ encoded at 64kb/s to be equivelant to a 128kb/s encoded MP3 in quality. Since Sony conducted that test, and it wasn't a double blind study as in the previous case, that opinion is heavily biased.

ATRAC™ and the PSP

This file format is the one used by games, PSMF files, and UMD movies. Sony claims that no computer software can play these files--only their devices--but RealPlayer appears to handle them.

To encode your own ATRAC™ files compatible with the PSP, you need SonicStage 3.0 (http://sonicstage.connect.com/SonicStageInstaller.exe), the application that Sony ships with many Minidisc recorders.