markov_chain.py

import os
# from mido import MidiFile
import mido
import music21
import numpy as np
import pandas as pd
from music21 import *
from mido import Message, MidiFile, MidiTrack
#number of notes to be used for prediction
window = 3

#num of notes to generate
#TODO: change this to accept values according to user
num_notes = 100

#midi ticks per quarter note, indicates tempo of track
quarter_note_ticks = 480

#accepted note durations: ranges from 16th note to whole dotted notes
accepeted_lengths = [0.25,0.375,0.5,0.75,1,1.5,2.0,3.0,4.0]
#Finds all absolute paths in directory
#https://stackoverflow.com/questions/9816816/get-absolute-paths-of-all-files-in-a-directory
def abs_paths(dir):
    for dir_path,_,filenames in os.walk(dir):
        for f in filenames:
            yield os.path.abspath(os.path.join(dir_path, f))
def pitch_to_int(nameWithOctave):
    # letter names with corresponding values
    letter_dict = {'C':0,'D':2,'E':4,'F':5,'G':7,'A':9,'B':11}
    # parse characters from strings
    chars = list(nameWithOctave)
    # convert octave number to corresponding midi value
    octave = 12*(int(chars[-1])+1)
    # select value from letter_dict using first character
    note = letter_dict[chars[0]]
    # set accidental value
    accidental = 0
    # does accidental exist?
    if not len(chars)==2:
        # increase (sharp) or decrease (flat) value by one
        accidental = 1 if chars[1]=='#' else -1
    # return sum of these numbers, middle C(4) == 60
    return octave + note + accidental
def generate_notes():
    df_notes = pd.read_csv('prepared.csv')
    print(df_notes.shape)
    # define arrays for generated notes and durations
    gen_notes = []
    gen_durations = []
    # define note and duration feature columns based on names
    features = df_notes.columns[:-2]
    note_features = [s for s in features if "note" in s]
    duration_features = [s for s in features if "duration" in s]
    # define target columns
    note_target = df_notes.columns[-2]
    duration_target = df_notes.columns[-1]

    # sample random row from dataframe and define start notes and durations
    initial_sample = df_notes.sample()
    start_notes = list(initial_sample[note_features].values[0])
    start_durations = list(initial_sample[duration_features].values[0])
    # append starting notes and durations to gen arrays
    for note in start_notes:
        gen_notes.append(int(note))
    for duration in start_durations:
        gen_durations.append(duration)

    for i in range(num_notes) :
        rows = df_notes
        for i in range(window-1):
            rows = rows.loc[df_notes[note_features[i]] == start_notes[i]]
            rows = rows.loc[df_notes[duration_features[i]]== start_durations[i]]
    
        #This gives the same effect as probability.
        # We effectively sample from a list which might have more than 1 C note, Hence increasing its probability
        #Sometime, The start_notes and durations could be selected in such a way that we cannot generate any further notes uptill num_notes,
        #This means there maybe some combinations of notes such as 76,68 which are not there in the dataset and hence cannot be sampled.
        #In such cases, the only way about it would be to reset the start notes, because we cannot sample from an empty row 
        #So here we check if any rows which we ta
        if len(rows):
            next_sample = rows.sample()
            next_note = next_sample[note_target].values[0]
            next_duration = next_sample[duration_target].values[0]
            gen_notes.append(int(next_note))
            gen_durations.append(next_duration)

            start_notes.pop()
            start_durations.pop()

            start_notes.append(next_note)
            start_durations.append(next_duration)
        else:
            #Received empty row
            # print("Exiting!!!!!!")
            #restarting again to get new start notes
            return [],[]
           
        # print(rows[note_target].value_counts(normalize=True))
        # print(rows[duration_target].value_counts(normalize=True))

    return gen_notes, gen_durations

#MAIN FUNCTION
if __name__=="__main__":
    # https://stackoverflow.com/questions/49462107/how-can-i-get-all-piano-parts-from-a-music21-score
    if not os.path.exists('tracks'):
        os.mkdir('tracks')
        i = 0
        #Parse midi files into tracks folder
        for path in abs_paths('data'):
            print(path)
            # mid = MidiFile(path)
            piece = converter.parse(path)
            print(list(piece.parts))
            for part in piece.parts:
                part_notes = []
                #get all note messages from all tracks
                for event in part:
                    if getattr(event, 'isNote', None) and event.isNote:
                        print('note in {}'.format(part))

                        #check if note is in accepted length
                        #convert string to numerical value 
                        if event.quarterLength in accepeted_lengths:
                            part_notes.append([pitch_to_int(event.nameWithOctave), event.quarterLength])
                if not len(part_notes) == 0:
                    np.save('tracks/{}.npy'.format(i), np.array(part_notes))
                    i+=1
        print('Number of tracks parsed: {}'.format(i))
    if not os.path.exists('prepared.csv'):
        columns = []
        for i in range(window):
            columns.append('note' + str(i))
            columns.append('duration' + str(i))
        df_notes = pd.DataFrame(columns=columns)
        # append segments from each track as rows to dataframe
        for path in abs_paths('tracks'):
            notes = np.load(path)
            for i in range(len(notes)-window):
                # take every x notes and durations
                segment = notes[i:i+window].flatten()
                # make into pd.Series row
                row = pd.Series(segment, index=df_notes.columns)
                # append row to dataframe
                df_notes = df_notes.append(row, ignore_index=True)
        # export
        df_notes.to_csv('prepared.csv', index=False)
    success = False
    gen_notes =[]
    gen_durations =[]

    #Retry mechanism
    while len(gen_notes)<num_notes:
            gen_notes,gen_durations = generate_notes()

# import
# df_notes = pd.read_csv('prepared.csv')
# print(df_notes.shape)
# # define arrays for generated notes and durations
# gen_notes = []
# gen_durations = []
# # define note and duration feature columns based on names
# features = df_notes.columns[:-2]
# note_features = [s for s in features if "note" in s]
# duration_features = [s for s in features if "duration" in s]
# # define target columns
# note_target = df_notes.columns[-2]
# duration_target = df_notes.columns[-1]

# # sample random row from dataframe and define start notes and durations
# initial_sample = df_notes.sample()
# start_notes = list(initial_sample[note_features].values[0])
# start_durations = list(initial_sample[duration_features].values[0])
# # append starting notes and durations to gen arrays
# for note in start_notes:
#     gen_notes.append(int(note))
# for duration in start_durations:
#     gen_durations.append(duration)


# for i in range(num_notes) :
#     rows = df_notes
#     for i in range(window-1):
#         rows = rows.loc[df_notes[note_features[i]] == start_notes[i]]
#         rows = rows.loc[df_notes[duration_features[i]]== start_durations[i]]
    
#     #This gives the same effect as probability.
#     # We effectively sample from a list which might have more than 1 C note, Hence increasing its probability
#     #Sometime, The start_notes and durations could be selected in such a way that we cannot generate any further notes uptill num_notes,
#     #This means there maybe some combinations of notes such as 76,68 which are not there in the dataset and hence cannot be sampled.
#     #In such cases, the only way about it would be to reset the start notes, because we cannot sample from an empty row 
#     #So here we check if any rows which we ta
#     if len(rows):
#         next_sample = rows.sample()
#         next_note = next_sample[note_target].values[0]
#         next_duration = next_sample[duration_target].values[0]
#         gen_notes.append(int(next_note))
#         gen_durations.append(next_duration)

#         start_notes.pop()
#         start_durations.pop()

#         start_notes.append(next_note)
#         start_durations.append(next_duration)
#     else:
#         #Received empty row
#         print("Exiting!!!!!!")
# print(rows[note_target].value_counts(normalize=True))
# print(rows[duration_target].value_counts(normalize=True))

    print('Generated  notes/durations'.format(num_notes))
    print(gen_notes)
    print(gen_durations)

    mid = MidiFile()
    track = MidiTrack()
    mid.tracks.append(track)
    for i in range(num_notes):
        track.append(Message('note_on', channel=0, note=gen_notes[i], velocity=60, time=0))
        track.append(Message('note_on', channel=0, note=gen_notes[i], velocity=0,time=int(gen_durations[i]*quarter_note_ticks)))
    mid.save('new_song.mid')
#create new midi file which can be engraved
#https://mido.readthedocs.io/en/latest/midi_files.html , crreating a New file sectoin
# mid = MidiFile()
# track = MidiTrack
# mid.tracks.append(track)

# for i in range(num_notes):
#     track.append(Message('note_on', channel=0, note=gen_notes[i], velocity=60, time=0))
#     track.append(Message('note_on', channel=0, note=gen_notes[i], velocity=0,time=int(gen_durations[i]*quarter_note_ticks)))
# mid.save('output.mid')
# def inspect_midi():
#     #Just inspecting midi file 1.
#     for path in abs_paths('data'):
#         # print(path)
#         mid = MidiFile(path)
#         for i, track in enumerate(mid.tracks):
#             print('Track {}: {}'.format(i, track.name))
#             for message in track:
#                 print(message)
#         break
# inspect_midi()
# def isolate_note_on_msgs():
#     #round each note duration to 250ms
#     #Build adjaceny matrix


# LILYPOND COMMANDS : To be used for generating music scores
# Installation : sudo apt-get install -y lilypond
# !midi2ly "new_song.ly"
# !lilypond -fpng "new_song-midi.ly"