Transcribe! is an assistant for working out a piece of music from a recording. It offers many features aimed at making the transcription job smoother and easier, including the ability to slow down the music without changing its pitch, and to analyse chords and show you what notes are present.
MOC (music on console) is a console audio player with a simple ncurses interface in playmp3list style. It supports MP3 (with ID3 tag, VBR, and Xing headers), Ogg, FLAC, WAVE, Musepack, Speex, WMA, MP4, AAC, and some other less popular audio formats. Playlists can be saved and loaded using .m3u files (PLS version 2 can also be loaded). Internet streams (Shoutcast, Icecast) are supported. It achieves gapless playback by employing an output buffer in a separate thread and file pre-caching. The key mapping can be fully customized. The interface can be detached from the server as it plays in the background.
MP3 Diags finds problems in MP3 files and helps the user fix many of them. It looks at both the audio part (VBR info, quality, normalization) and the tags containing track information (ID3). It has a tag editor, which can download album information (including cover art) from MusicBrainz and Discogs, as well as paste data from the clipboard. Track information can also be extracted from a file's name. Another component is the file renamer, which can rename files based on the fields in their ID3V2 tag (artist, track number, album, genre, etc.).
DR14 T.meter is a commandline tool for computing the Dynamic Range of your music according to the procedure used in the offline meter released by the Pleasurize Music Foundation. It is very useful to measure how loud your music is and to understand that a good quality album always has a good dynamic. It's also useful for understanding the effects of the so-called loudness war.
Music Player Daemon (MPD) is a server that allows remote access for playing music in various formats and managing playlists. It makes a great desktop player with frontend options (Qt, GTK, ncurses, Windows, and Web clients are available). It is also appropriate as a console player that is scriptable, and is especially useful if X is restarted frequently. A set of rapid development tools for clients are being developed and include a C library, Python module, PHP class, Perl module, and Java Class. The goals are to be easy to install and use, to have minimal resource requirements, to be stable and flexible, and easy to interface.