MP3

A lossy audio compression format, Not the most efficient, but by far the most widely used for encoding and sharing music. Attains decent quality at 128 kbps, and good quality at 192kbps. Maximum accepted bitrate is usually 320kbps. Files are generally encoded in variable bit rate, as it offers a more efficient use of space.

An attempt at a successor was made with the mp3pro format, more efficient but less compatible. This failed because of the lack of support from third parties.