MIDI Support¶

Installation¶

MIDI support need some extra dependencies. The main dependencie is mido wich is installed whith python-rtmidi as default backend. To install the library with MIDI support use the following command:

pip install sc3[midi]

Or, if sc3 whas already installed without MIDI install mido and python-rtmidi libraries directly from PyPI.

pip install mido python-rtmidi

The MIDI backend is automatically initialized and uses default mido’s configuration. To configure mido’s backend see its documentation.

If using pipewire, e.g. on Fedora, install pipewire’s development files for jack and manually add the linking location before pip install for python-rtmidi.

sudo dnf install pipewire-jack-audio-connection-kit-devel
LIBRARY_PATH=/usr/lib64/pipewire-0.3/jack/ pip install python-rtmidi

Usage¶

In rt mode, messages can be received or sent through MidiIn and MidiOut instances which work seamlessly with MidiFunc and events. To list MIDI ports available to connect as inputs to the library use the sources class method of MidiIn.

MidiIn.sources()

And, for listing MIDI ports available as targets of the library use the destination class method of MidiOut.

MidiOut.destinations()

Inputs and outputs can be instantiated in two different ways. To connect a library input or output to an existing source or destination, objects can be instantiated with the name listed by the corresponding methods.

src_name = MidiIn.sources()[1]
mi = MidiIn(src_name)
dst_name = MidiOut.destinations()[1]
mo = MidiOut(dst_name)

Receiving MIDI:

from sc3.all import *

mi = MidiIn('sc3 input 0', True)
mo = MidiOut(mi.name)

@midifunc(['note_on', 'note_off'])
def f(msg, mi):
    print(msg, mi)

play(type='midi', midiout=mo, midinote=84)
# {'type': 'note_on', 'time': 0, 'note': 84, 'velocity': 12, 'channel': 0} MidiIn('sc3 input 0', False)
# {'type': 'note_off', 'time': 0, 'note': 84, 'velocity': 12, 'channel': 0} MidiIn('sc3 input 0', False)

Sending MIDI:

play(type='midi', midiout=mo, midinote=84, velocity=12)

event(type='midi', midiout=mo, midinote=84).play()

event({'type': 'midi', 'midiout': mo, 'midinote': 84}).play()

mo.send_msg('note_on', note=84, velocity=12)
mo.send_msg('note_off', note=84, velocity=12)

Mido’s representation¶

In this library the objects MidiIn and MidiOut mimic the behavior of NetAddr and send_msg for OSC commands but adapted to MIDI messages.

Events and MidiOut.send_msg use mido’s dictionary based representation which gets along with SuperCollider’s event model. Instead of providing long and confusing exmplantions about which message’s bits does what, mido uses names for different types of messages and parameters which are fairly easyeasier to remember and produces more meaningful code.

For events that define midi messages the type key should be set to ‘midi’ and can be used with the play function event objects. When using MidiOut.send_msg directly the first argument is the event type and its attributes are passed as keyword arguments as shown in the examples above.

See mido’s documentation for more details about message attributes.

MIDI in NRT¶

MIDI files can also be created with NRT scripts using the resources of the library, e.g. routines and patterns.

Script example using routines:

from sc3.all_nrt import *

mo = MidiOut('channel 1')

@routine
def r():
    mo.send_msg('note_on', note=72, velocity=64)
    yield 1
    mo.send_msg('note_off', note=72, velocity=64)
    for i in range(3):
        play(type='midi', midiout=mo, midinote=60 + i, velocity=64, legato=1)
        yield 1

r.play()

score = main.process(proto='midi')
print(score.duration)
score.write('test.mid')

Script example using patterns:

from sc3.all_nrt import *

mo = MidiOut('channel 1')

clock = TempoClock(90/60)

Pbind({
    'midinote': Pxrand([0, 2, 4, 7, 9, 12], 30) + 60,
    'dur': 0.25,
    'velocity': 64,
    'sustain': 1
}).play(clock, proto={'type': 'midi', 'midiout': mo})

score = main.process(proto='midi')
print(score.duration)
print(score.list)
score.write('test.mid')