Tutorial 1 - Playing Containers with FluidSynth

FluidSynth is a MIDI synthesizer which uses SoundFont (.SF2) files to generate audio. To work with this module, you’ll need the FluidSynth library (usually packaged with the stand-alone program) and a nice instrument collection (look here: http://www.hammersound.net, go to Sounds -> Soundfont Library -> Collections).

>>> from mingus.midi import fluidsynth

Loading a SoundFont

To load the SoundFont and initialize FluidSynth we’ll only have to call init.

>>> fluidsynth.init("soundfont.SF2")

You can give an optional second argument to specify a driver (one of ‘alsa’, ‘oss’, ‘jack’, ‘portaudio’, ‘sndmgr’, ‘coreaudio’ or ‘Direct Sound’), otherwise the default driver for the system will be used.

>>> fluidsynth.init("soundfont.SF2", "alsa")

Playing mingus.containers Objects

play_Note

play_Note(note, channel = 1, velocity = 100) converts the given Note object to a midi note on command on channel. The velocity (0-127) stands for the speed with which the notes are hit. This roughly translates to volume.

>>> fluidsynth.play_Note(Note("C-5"))
True
>>> fluidsynth.play_Note(Note("E-5"))
True

The channel and velocity can be set as Note attributes as well. If that’s the case those values take presedence over the ones given here as function arguments.

>>> n = Note("C-5")
>>> n.channel = 5
>>> n.velocity = 50
>>> fluidsynth.play_Note(n)
True

stop_Note

If a playing note needs to be stopped, stop_Note(note, channel = 1) can be used.

>>> fluidsynth.stop_Note(Note("C-5"), 1)
True

Note it doesn’t matter if the note is actually playing; ie. nothing will break when you try to stop a note that is already stopped.

Playing and Stopping NoteContainers

play_NoteContainer(notecontainer, channel = 1, velocity = 100) and stop_NoteContainer(notecontainer, channel = 1)` work the same as play_Note and stop_Note.

>>> fluidsynth.play_NoteContainer(NoteContainer(["C", "E"]))
True
>>> fluidsynth.stop_NoteContainer(NoteContainer(["C", "E"]))
True

Playing Bars, Tracks and Compositions

play_Bar, play_Track and play_Composition all take three arguments. The first is the object itself, the second is the channel which defaults to 1, and the last one is the number of beats per minute which denotes tempo.

>>> b = Bar()

# Fill the Bar with NoteContainers.

>>> fluidsynth.play_Bar(b, 1, 150)

Note You can set a bpm attribute on a NoteContainer to change the tempo. Furthermore, you can set a Track’s instrument attribute to a MidiInstrument object so that play_Track and play_Composition know which instrument to use.

Misc. MIDI Commands

Change the Instrument

set_instrument(channel, instr, bank = 0) can be used to change the instrument that is being used on a channel. You can find a list of instruments by googling for midi instruments table, but you can also use the names attribute in the MidiInstrument class found in mingus.containers.Instrument.

>>> fluidsynth.set_instrument(1, 14)

Panning, Modulation and Other Control Change Commands

panning(channel, value) and modulation(channel, value) are shortcuts to the control_change(channel, control, value) function added for your convenience. There are more control change commands however. You can find tables by googling, but know that FluidSynth ignores some of the commands.

You can learn more about mingus.midi.fluidsynth in the reference section.