developer unofficially ported Rockbox to Palm's WebOS. 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 playback screens. These themes can include backgrounds and other images (such as icons), plus various formats for file names, ID3 tags, album art, file progress, and time and system information. Rockbox has essentially been a file-tree based player, to which folders could be dragged and dropped and then navigated by folder structure. However, more recent versions have included a complementary database feature which allows the player to compile information from the files' ID3 tags. The user can then navigate the files regardless of file structure. Features Target status Rockbox has many features additional to those supported by the original operating firmware, but in many cases there are limitations. On platforms classified as "stable" and supported, the device can be used as a digital music player, but even on some such platforms Rockbox does not support charging or USB; the player must be dual-booted into the original firmware to be charged or to transfer files. Some platforms are classified as "unstable", but supported; those deemed "unusable" are not supported, and their use is not recommended. Some porting projects are in a pre-development hunting and gathering stage, with no code written. Codecs Rockbox on software decoding platforms (non-Archos) supports playback of twelve lossy codecs (depending on how one counts), five lossless, two uncompressed and twelve miscellaneous formats. This makes a conservative total of 30 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 Vorbis, WMA, APE, TTA, MPC, Wavpack, ATRAC3, Cook and WMA Pro among the fastest known integer implementations for those formats. Lossy formats MPEG audio layers I-III (MP3/MP2/MP1) Ogg Vorbis MPEG-4 AAC(-LC/HE/HEv2 profiles) (in MP4 or RM containers) Musepack AC3 (raw or RM container) WMA Standard WMA Professional Speex Cook ATRAC3 The lossy portion of WavPack hybrid files Opus Lossless formats FLAC ALAC WavPack Shorten Monkey's Audio TTA Uncompressed formats WAV AIFF Together they include over a dozen different PCM and ADPCM formats. Miscellaneous formats In addition, there are playback of game audio types ADX, SID, NSF, SAP, SPC, AY,