MIDI file

MidiFileOutputDevice

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

isobar-ext 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.

Multi track midi files are possible - see sel_track parameter.

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)}, sel_track=0)
timeline.schedule({ "note": iso.PSequence([ 71, 72, 74, 75 ], 1)}, sel_track=1)

timeline.run()
output.write()

Mutlitrack with list of dictionary provided:

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

timeline = iso.Timeline(iso.MAX_CLOCK_RATE, output_device=output)
timeline.stop_when_done = True
events_1 = { "note": iso.PSequence([ 60, 62, 64, 65 ], 1), "args":  {'track_idx': 0}}
events_2 = { "note": iso.PSequence([ 71, 72, 74, 75 ], 1), "args":  {'track_idx': 1}}

timeline.schedule({ "note": iso.PSequence([ 60, 62, 64, 65 ], 1)}, sel_track=0)
timeline.schedule({ "note": iso.PSequence([ 71, 72, 74, 75 ], 1)}, sel_track=1)

timeline.run()
output.write()

events_1 = { iso.EVENT_NOTE: iso.PSequence(sequence=[50, 52, 55, 57], repeats=1) , iso.EVENT_DURATION: iso.PSequence(sequence=[0.5, 1, 1, 1.5], repeats=1) , iso.EVENT_CHANNEL: 0 , iso.EVENT_ACTION_ARGS: {'track_idx': 0} }

events_2 = { iso.EVENT_NOTE: iso.PSequence(sequence=[75, 69, 72, 66], repeats=1) , iso.EVENT_DURATION: iso.PSequence(sequence=[1, 1, 1, 1], repeats=1) , iso.EVENT_CHANNEL: 2 , iso.EVENT_ACTION_ARGS: {'track_idx': 5} }

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, action), or with optional MidiFileInputDevice.read(multi_track_file=True) returns list of PDict:s containing PSequence which can be scheduled for playback within a timeline:

Single track read

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

Multi track read

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

Parameter multi_track_file is optional with default value False to ensure backward compatibility between isobar-ext on single track isobar. Additionally isobar-ext handles effectively action events (e.g. set_tempo midi message).

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()