MIDI file

MidiFileOutputDevice

Writing MIDI files is done by setting the output device of a Timeline to a MidiFileOutputDevice

isobar normally generates events in real-time according to the tempo of the Timeline. To batch process events instantaneously, set the tempo of the timeline to iso.MAX_CLOCK_RATE.

filename = "output.mid"
output = MidiFileOutputDevice(filename)

timeline = iso.Timeline(iso.MAX_CLOCK_RATE, output_device=output)
timeline.stop_when_done = True
timeline.schedule({ "note": iso.PSequence([ 60, 62, 64, 65 ], 1) })

timeline.run()
output.write()

MidiFileInputDevice

Reading MIDI files is done with a MidiFileInputDevice.

The method MidiFileInputDevice.read() returns a PDict containing PSequence patterns for each of the MIDI event properties (note, amplitude, duration), which can be scheduled for playback within a timeline:

pattern = MidiFileInputDevice(args.filename).read()
timeline = iso.Timeline()
timeline.schedule(pattern)
timeline.run()

To discard the amplitudes and durations, and make use of just the pitch values:

pattern = MidiFileInputDevice(args.filename).read()
timeline = iso.Timeline()
timeline.schedule({
    "note": pattern["note"],
    "duration": 0.1
})
timeline.run()