MIDIの特定の小節を取り出してランダムにtransposeするサンプル

.py

import random
import copy

from music21 import *

def init():
    # get environment
    env = environment.Environment()

    # check the path
    print('Environment settings:')
    print('musicXML:  ', env['musicxmlPath'])
    print('musescore: ', env['musescoreDirectPNGPath'])

    # set path if necessary
    env['musicxmlPath'] = 'C:/Program Files/MuseScore 4/bin/MuseScore4.exe'
    env['musescoreDirectPNGPath'] = 'C:/Program Files/MuseScore 4/bin/MuseScore4.exe'

def part_transpose(part,transpose):
    part_elements = part.flat.getElementsByClass(['Note', 'Chord', 'Rest'])

    part.show("Text")
    out_elements = []


    for i, element in enumerate(part_elements):
        duplicated_element = copy.deepcopy(element)
        if part.partName == "Drum":
            pass
        else:
            if not isinstance(element, note.Rest):
                # トランスポーズで全体のキーを変える
                duplicated_element = duplicated_element.transpose(transpose)

        print(duplicated_element)
        out_elements.append(duplicated_element)

    return out_elements;

def analyze_mid(midi_file_path):
    # MIDIファイルを読み込む
    midi_stream = converter.parse(midi_file_path, quantizePost=False, normalize=False)

    midi_stream.write('midi',"D:/tatPython/midichord/test_out.mid")

    # sp = midi.realtime.StreamPlayer(midi_stream.measures(1,2))
    # sp.play()

    # MIDIファイルの内容を表示
    # midi_stream.show()

    # MIDIストリームを２回繰り返す
    new_score = stream.Score()

    transpose = []
    lengthBias = []
    for _ in range(32):
        transpose.append(random.randint(0, 11))
        lengthBias.append(random.randint(1, 1))

    # score
    mm1 = midi_stream.measures(1, 2)
    mm2 = midi_stream.measures(3, 4)

    for part in mm2.parts:
        new_part = stream.Part()
        new_part.partName = part.partName
        print(new_part.partName)
        for j in range(16):
            new_elements = part_transpose(part,transpose[j])
            for element in new_elements:
                new_part.append(element)

        new_score.append(new_part)

    new_score.show()
    #
    sp = midi.realtime.StreamPlayer(new_score)
    sp.play()


if __name__ == '__main__':
    init()

    analyze_mid("D:/tatPython/midichord/test.mid")