music_loops/music_loops/tinkering.py

#!/usr/bin/env python

from midiutil import MIDIFile
from mingus.core import chords

NOTES = ['C', 'C#', 'D', 'Eb', 'E', 'F', 'F#', 'G', 'Ab', 'A', 'Bb', 'B']
OCTAVES = list(range(11))
NOTES_IN_OCTAVE = len(NOTES)

errors = {
    'notes': 'Bad input please refer this spec-\n',
}

def swap_accidentals(note):
    match note:
        case 'Db':
            return 'C#'
        case 'D#':
            return 'Eb'
        case 'E#':
            return 'F'
        case 'Gb':
            return 'F#'
        case 'G#':
            return 'Ab'
        case 'A#':
            return 'Bb'
        case 'B#':
            return 'C'
        case _:
            return note

def note_to_number(note: str, octave: int) -> int:
    note = swap_accidentals(note)
    assert note in NOTES, errors['notes']
    assert octave in OCTAVES, errors['notes']

    notenum = NOTES.index(note)
    notenum += (NOTES_IN_OCTAVE * octave)

    assert 0 <= notenum <= 127, errors['notes']

    return notenum


chord_progression = ["Cmaj7", "Cmaj7", "Fmaj7", "Gdom7"]

arpeggio_notes = []
bass_notes = []

for chord in chord_progression:
    arpeggio_notes.extend(chords.from_shorthand(chord))
    bass_notes.append(chords.from_shorthand(chord)[0])

arpeggio_octave = 4
arpeggio_nums = [note_to_number(x, arpeggio_octave) for x in arpeggio_notes]

bass_octave = 3
bass_nums = [note_to_number(x, bass_octave) for x in bass_notes]

arpeggio_track = 0
bass_track = 1
channel = 0
time = 0       # in beats
arpeggio_duration = 1   # in beats
bass_duration = 4   # in beats
tempo = 120    # in BPM
volume = 100   # 0-127

MyMIDI = MIDIFile(2) # two tracks, defaults to format 1
                     # tempo track is created automatically
MyMIDI.addTempo(arpeggio_track, time, tempo)

for i, pitch in enumerate(arpeggio_nums):
    MyMIDI.addNote(arpeggio_track, channel, pitch, time + i, arpeggio_duration, volume)

for i, pitch in enumerate(bass_nums):
    MyMIDI.addNote(bass_track, channel, pitch, time + (i*4), bass_duration, volume)


with open("pure-edm-fire-arpeggio.mid", "wb") as output_file:
    MyMIDI.writeFile(output_file)

# print(arpeggio_notes)