GstPUID is a GStreamer element that allows for fingerprint-based detection of music files using MusicDNS/MusicIP and Musicbrainz. It allows for detection of the track's artist and title based on the audio data only. It works with any file format that is supported by GStreamer. It is geared towards developers; an example application is included that should make clear how the element is to be used.
soniK is a digital audio editor for the KDE platform. It allows you to record, edit, and process sounds on your computer. Its main features include recording and playback using your computer's sound card, visualization of the audio as a waveform or a spectrogram, the ability to edit audio and transform it with a wide variety of plugins, and the generation of new sounds.
PyChoReLib is a Python library which transforms lists of notenames to a chordname. The system uses built-in music theory knowledge to make it easy and quick to add support for new chord types. Its features include interval recognition, scale recognition, and demo chord recognition using real-time input from MIDI devices.