video2midi is an open source crossplatfrom utility, written in python for creating midi file from Synthesia video and the like.. Works on GNU/Linux, *BSD, Windows, may be works on Mac with anaconda2 but on Mac not tested...
The abcMIDI suite consists of programs for turning ABC music files into MIDI and vice versa, typesetting them as PostScript files, and manipulate them in several ways.
QXGEdit is a Qt4 GUI for editing MIDI system exclusive files. It works with XG devices such as Yamaha DB50XG. It requires a configured ALSA system.
SpectMorph is a free software project which allows to analyze samples of musical instruments, and to combine them (morphing). It can be used to construct hybrid sounds, for instance a sound between a trumpet and a flute; or smooth transitions, for instance a sound that starts as a trumpet and then gradually changes to a flute.
Beast is a music composition and modular synthesis application. As input methods, it offers a multitrack editor, a piano roll, and supports pattern editing. It has a wide range of technical abilities like sequencing, unlimited undo/redo history, real-time synthesis with multiprocessor support, full duplex 32-bit audio rendering, seeking at sample granularity, on demand loading of partial wave files, on the fly decoding of various sample formats, aliasing free oscillators, and full scripting supp
MusE is a MIDI/Audio sequencer with recording and editing capabilities written originally by Werner Schweer now developed and maintained by the MusE development team. MusE aims to be a complete multitrack virtual studio for Linux, it is published under the GNU General Public License.
EasyABC is an open source ABC editor for Windows, OSX and Linux. It uses abcm2ps and abcMIDI for typesetting the score and playing the music.
fmmidi is a player for Standard MIDI music file(s). It emulates the Yamaha YM2608 FM synthesizer and it uses this emulation to play the musics in MIDI format.
FLTracker is MIDI sequencer for Linux with a FLTK GUI. It runs on ALSA, lists track numbers, output device and MIDI channel, notes, volume, effects and parameters; understands GM patches, drum sounds, and controllers.
Drumstick Metronome (kmetronome) is a MIDI-based metronome utilizing the ALSA sequencer. It's intended for students and musicans to aid rythm consistency while playing instruments. It incurs little overhead by using MIDI instead of digital audio playback, which also keeps the timing more accurate.
Mutabor is a microtuner, that is a program that allows performing and composing microtonal music using a normal MIDI keybord. But it's powerful description language is intended to allow permanent retunings and tuning logics in to describe, what's actually goes on. This allows a musician to use tone systems and pitch spaces which are outside of the scope of keyboard instruments, e.g. unlimited just intonation (Tonnetz) as described bei Martin Vogel or fast changing tunings as it is necessary f
SongBase (formerly known as Song Builder) can be used for music creation. It allows to mix up to 15 instrumental voices and percussion tracks. About 128 instruments or a custom soundbank can be used. It allows quick editing as it uses JFugue MusicString notation, either using note names and octaves or by MIDI values and durations numerically or through character codes. Note sequences can be nested within patterns. Further features include MIDI and MusicXML export, backup and restore, a shared SQ