2.02 Random Melody

The Melody plays completely random in a range bit more than two octaves. Note duration and rests are set by controlled random.

from pyknon.genmidi import Midi
from pyknon.music import Rest, Note, NoteSeq
import numpy as np

Instruments: Available are at lest the 128 General-Midi (GM) Instruments. Depending on the sound-fonts there is a bigger choice. A list of the GM instruments can be found here. https://en.wikipedia.org/wiki/General_MIDI#Program_change_events Remember to subtract 1, as the list starts with 1 and not 0.

major = np.array([-12, -10, -8, -7, -5, -3, -1, 0, 2, 4, 5, 7, 9, 11, 12, 14, 16])
minor = np.array([-12, -10, -9, -7, -5, -4, -2, 0, 2, 3, 5, 7, 8, 10, 12, 14, 15])
var   = np.array([1,2,-1])
var2  = np.array([0,2,-1])
var3  = np.array([0,-1,2])

def fade(start,end,steps):
    fade = np.around( np.linspace(start,end,num=steps))
    fade = fade.astype(int)
    return fade

def ran_duration(duration, prob_duration, melody_len):
    duration= np.asarray(duration)                  # this are the allowed durations of the notes
    prob_duration = np.asarray(prob_duration)       # this are the probabilities how often each will occure
    prob_duration = prob_duration/np.sum(prob_duration)
    rythem = np.r_[np.random.choice(duration, size=melody_len, p=prob_duration)]
    return rythem

def ran_volume(volume, prob_volume, melody_len):
    volume = np.asarray(volume, dtype=int)         # this are the allowed volumes of thenotes
    prob_volume = np.asarray(prob_volume)          # this are the probabilities how often each volume will occure
    prob_volume = prob_volume/np.sum(prob_volume)
    volumes = np.r_[np.random.choice(volume, size=melody_len, p=prob_volume)]
    return volumes

tune_K: Creating a track with complete random melody and controlled random rhythm

def tune_K():
    tune_name = 'tune_K'  # Complete random melody
    np.random.seed(12)
    melody_len = 20
    imelody1 = np.random.randint(len(minor), size=melody_len) # creat melody in index form
    melody1 = minor[imelody1]

    imelody2 = np.random.randint(len(minor), size=melody_len) # creat melody in index form
    melody2 = minor[imelody2]

    rythem1 = ran_duration([1/8, 1/4,1/2], [4,2,1], melody_len)
    rythem2 = ran_duration([1/8, 1/4,1/2], [4,2,1], melody_len)
    volumes1 = ran_volume([0,100], [1,4], melody_len )
    volumes2 = ran_volume([0,120], [1,4], melody_len )

    notes1 = NoteSeq( [Note(no+4,octave=5, dur=du, volume=vo) for no,du,vo in zip(melody1,rythem1,volumes1)] )
    notes2 = NoteSeq( [Note(no-8,octave=5, dur=du, volume=vo) for no,du,vo in zip(melody2,rythem2,volumes2)] )
    instruments = [45,68]
    notes = [notes1, notes2]
    return notes, instruments,tune_name

tune_K
tune_K

def gen_midi():
#     squezze into a MIDI framework
    notes, instruments, tune_name = tune_K() #  <--- select a tune  <<--     <<<<<<<<<--- select a tune -----
    nTracks = len(notes)

    m = Midi(number_tracks=nTracks, tempo=120, instrument=instruments)
    for iTrack in range(nTracks):
        m.seq_notes(notes[iTrack], track=iTrack)

    #--- write the MIDI file -----
    midi_file_name = tune_name +'.mid'   # set the name of the file
    m.write(midi_file_name)
    return midi_file_name

Midi: Play and Generate audio-file

External players offered a better sound quality in comparison with python libraries. We use VLC and Musescore

import subprocess
default_soundfont = '/usr/share/sounds/sf3/MuseScore_General.sf3'

def midi_play(midi_in, soundfont= default_soundfont):
    subprocess.call(['cvlc', midi_in , 'vlc://quit'])   # cvlc = vlc without gui

def midi_audio(midi_in, name_out = 'none', soundfont= default_soundfont):
    if name_out == 'none' :
        name_out = midi_in.replace('.mid', '.flac')
    else:
        name_out = name_out + '.flac'
    subprocess.call(['mscore', '-o', name_out, midi_in]) # -o = export as

def midi_png(midi_in, name_out = 'none'):
    if name_out == 'none' :
        name_out = midi_in.replace('.mid', '.png')
    else:
        name_out = name_out + '.png'
    subprocess.call(['mscore', '-o', name_out, '-T', '2', midi_in]) # -o = export as , -T 0 = cut page with 0 pixel

######---  Main  ---######
midi_file_name = gen_midi()

midi_play(midi_file_name)
midi_audio(midi_file_name)
midi_png(midi_file_name)