Rockbox is a free software / open source operating system for digital audio players (DAPs). It is released under the GNU General Public License (GPL) - a free software license. The Rockbox project began in late 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 replaces 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.

Rockbox runs on a wide variety of devices with very different hardware abilities: from early Archos players with 1-bit charcell-based displays to modern high resolution color iPods and iriver players with digital optical audio hardware and advanced recording capabilities.

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 loading either Rockbox from the hard disk or, alternatively, the original factory firmware.

Development

Rockbox was first designed for the early Archos series of hard-disk based MP3 players and player/recorders, including the flash-only model Ondio. These devices have relatively weak main CPUs and instead offload music playback to dedicated hardware MP3 decoding chips (called the MAS). Rockbox, therefore, was unable to significantly alter playback capabilities. Instead, it offered a greatly improved user interface and added plugin functionality not present in the factory firmware. Rockbox is capable of being permanently flashed into flash memory on the Archos devices, making it a literal firmware replacement.

Versions of Rockbox have since been produced for more sophisticated devices. These perform audio decoding in software, allowing Rockbox to potentially support many more music formats than the original firmware as well as bringing the extensibility and increased functionality already present in the Archos ports. Rockbox is run from the hard disk on these devices, after being started with a custom bootloader, so to upgrade Rockbox users need only copy the files onto the player's drive and restart the device. Reflashing is only necessary when changing the bootloader.

The first of these ports, beginning in late 2004, was for the ColdFire-powered devices manufactured by iriver, focusing on the H1xx series of hard drive players (H110/H120/H140). Approximately one year later a port for the H3xx series became functional, offering similar functionality.

In November 2005, work began on a port of Rockbox to Apple iPod portable players. As of February 2006, the port is stable and most features are available on all supported models (iPod photo, iPod nano, iPod 4g, iPod Video 5g) including audio playback. Support for color screens was added shortly thereafter for all color targets (including the H3xx).

Rockbox is continuously developed, with new CVS builds being released several times a day. The development targets for 2006 are versions 3.0 and 3.1. Version 3.0, originally due in May 2006 but since delayed, is for the Archos and iRiver players. Version 3.1, planned for November 2006, should also include versions for the iPod and iAudio X5 players.

Customization

Subject to the limitations of each particular platform, the appearance of Rockbox can be customised in various ways. Fonts and foreground and background colours can be added and selected, while a simple markup language can be used to create themes for the menu and while-playing screens. These themes can include background and other images (such as icons), plus various formats for filenames, ID3 tags, file progress, time and system information. Album art is not supported by the main builds, but can be added by patches.

Rockbox has been essentially a file-tree based player, to which folder could be dragged and dropped, then navigated by folder structure. More recent versions, however, have included a Tagcache feature which allows the player to compile a database from information in the files' ID3 tags. The user can then navigate the files using this database regardless of file structure.

Screenshots

Features

Codecs

• MPEG audio (MP3/MP2/MP1)
• Ogg Vorbis
• Musepack
• AACAAC decoder is unoptimized. Currently it only runs realtime on the iPod targets for ≤ 128 kbit/s.
• AC3 (DVD audio)
• FLAC
• WavPack
• Shorten
• Apple Lossless
• WAV/AIFF

Other

• Gapless playback for all codecs
• Replay GainSoftware decoding targets only
• 5 band fully parametric equalizer
• OTF ("on the fly") playlists
• True random shuffle
• Custom UI themes
• Stereo recording to 16 bit, 44.1 kHz WAV (supporting devices)
• FM radio, including FM recording (supporting devices)
• Remote control (supporting devices)
• Digital SPDIF input/output (supporting devices)

Plugins