Rockbox is a GPL-compliant open source operating system for portable digital audio players (DAPs). The Rockbox Project began in 2001 and was first implemented on the Archos Studio DAP because of owner frustration with severe limitations in the manufacturer-supplied user interface and device operations.
Rockbox can completely replace the host device's operating system firmware and has matured to become an extensible, flexible platform that provides a plug-in architecture for adding PDA functionality, applications, utilities, and games, and has also managed to retrofit video playback functionality onto DAPs first released in mid-2000. Recently, Rockbox now includes a voice-driven user-interface suitable for operation by blind and visually impaired users.
Although Rockbox's official title is "Rockbox: Open Source Jukebox Firmware", in many instances it is not actually installed to (or run from) flash memory. Instead a minimal bootloader is installed in the supported device's flash which is capable of either loading Rockbox from the hard disk or, alternately, the original factory firmware.
Rockbox on software decoding platforms (non-Archos) supports playback of eleven lossy codecs (depending on how one counts), five lossless, two uncompressed and six miscellaneous formats. This makes a conservative total of 25 supported audio formats, although a few of them do not operate in realtime on all platforms. Extensive work has gone into optimizing each codec, with FLAC, Ogg, WMA, APE and WMA Pro among the fastest known implementations for those formats.
- MPEG audio layers I-III (MP3/MP2/MP1)
- Ogg Vorbis
- MPEG-4 AAC(-LC/HE/HEv2 profiles) (in MP4 or RM containers)
- AC3 (raw or RM container)
- WMA Standard
- WMA Professional
- The lossy portion of WavPack hybrid files
Beside the ability of playing and recording audio files, Rockbox offers many playback enhancements that other firmware packages may not have implemented yet. Listed below are a handful of these features.
- Gapless playback
- 5 band fully parametric equalizer
- Variable speed decoding with pitch correction
- OTF ("on the fly") playlists
- True random shuffle (fresh randomly shuffled list every time)
- Custom UI themes
- Dynamic Playlists (queue files to play next, or in other parts of a dynamic playlist)
- Stereo recording to WAV/AIFF/WavPack (lossless) and MP3 (supporting devices)
- FM radio, including FM recording (supporting devices)
- Remote control (supporting devices)
- Digital S/PDIF input/output (supporting devices)
- Last.fm support (even on players lacking RTC)
- Cue sheet support
- Changeable selector bar
- Album art
- Sleep timer
- Supported audio formats, Rockbox Manual
- Codec performance comparison, Hydrogenaudio Forums, accessed 2011-03-12
- Codec Featureset, Rockbox Manual, accessed 22 May 2011
- Crossfade, Rockbox Manual, accessed 22 May 2011
- Software decoding targets only
- Pitch, Rockbox Manual, accessed 22 May 2011
- MP3, WavPack and AIFF are available on non-Archos devices. Multiple sample rates and bitrates available (hardware-dependent).
- Recording, Rockbox Manual, accessed 22 May 2011]
- Some limitations – Details at Rockbox Wiki, accessed 2011-03-12
~ Text taken from Wikipedia entry