06-midi-out.py - Sending MIDI events from pyo.

This program gives an example of how to build an algorithm with python/pyo and then send MIDI events from the Server to a connected MIDI synthesizer (physical or virtual).

Available MIDI output methods (see the Server documentation for the details):

  • afterout(pitch, velocity, channel=0, timestamp=0)

  • bendout(value, channel=0, timestamp=0)

  • ctlout(ctlnum, value, channel=0, timestamp=0)

  • makenote(pitch, velocity, duration, channel=0)

  • noteout(pitch, velocity, channel=0, timestamp=0)

  • pressout(value, channel=0, timestamp=0)

  • programout(value, channel=0, timestamp=0)

  • sysexout(msg, timestamp=0)

import random
from pyo import *


s = Server()

# Open all MIDI output devices.

# Then boot the Server.

# Generates an audio ramp from 36 to 84, from
# which MIDI pitches will be extracted.
pitch = Phasor(freq=11, mul=48, add=36)

# Global variable to count the down and up beats.
count = 0

def midi_event():
    global count
    # Retrieve the value of the pitch audio stream and convert it to an int.
    pit = int(pitch.get())

    # If the count is 0 (down beat), play a louder and longer event, otherwise
    # play a softer and shorter one.
    if count == 0:
        vel = random.randint(90, 110)
        dur = 500
        vel = random.randint(50, 70)
        dur = 125

    # Increase and wrap the count to generate a 4 beats sequence.
    count = (count + 1) % 4

    print("pitch: %d, velocity: %d, duration: %d" % (pit, vel, dur))

    # The Server's `makenote` method generates a noteon event immediately
    # and the correponding noteoff event after `duration` milliseconds.
    s.makenote(pitch=pit, velocity=vel, duration=dur)

# Generates a MIDI event every 125 milliseconds.
pat = Pattern(midi_event, 0.125).play()