Rockbox is an open source firmware for mp3 players, written from scratch. It runs on a wide range of players.

Important Features:

– Supports over 20 sound codecs:
– MP3, OGG, WAV, FLAC, game console music and many more
– Navigate music by folders or tag database
– Gapless playback and crossfading
– Ability to create your own themes
– Album art support