karplusStrong.py

#This project will use karplus strong algorithm to generate musical overtones.
import sys, os
import time, random
import wave, math, argparse,pygame
import numpy as np
import random
from collections import deque
from matplotlib import pyplot as plt 

gShowPlot = False

pmNotes = {'C4': 262 , 'Eb': 311, 'F': 349 , 'G': 391, 'Bb': 466}

def writeWAVE(fname, data):
    file = wave.open(fname , 'wb')
    nChannels = 1
    sampleWidth = 2
    frameRate = 44100
    nframes = 44100

    file.setparams((nChannels,sampleWidth,frameRate,nframes,'NONE','noncompressed'))
    file.writeframes(data)
    file.close() 

# we will now how sound is simulated using karplus-strong algorithm

def generateNote (freq):
    nSamples = 44100
    sampleRate = 44100
    N = int(sampleRate/freq)
    #starting the ring buffer 
    buf = deque([random.random() - 0.5 for i in range(N)])
    
    #intitializing buffer

    if gShowPlot:
        axline, = plt.plot(buf)               

    samples = np.array([0]*nSamples, 'float32')
   
    for i in range(nSamples):
        samples[i] = buf[0]
        avg = 0.966*0.5*(buf[0] + buf[1])
        buf.append(avg)
        buf.popleft()

        if gShowPlot:
            if i % 100 == 0:
                axline.set_ydata(buf)
                plt.draw()
   

    #converting to 16 bit
    smaples = np.array(samples*32767, 'int16')
    return samples.tostring()
#playing WAV file 
class NotePlayer:
    #constructor
    def __init__(self):
        pygame.mixer.pre_init(44100, -16, 1, 2048)
        pygame.init()
        #dic of notes
        self.notes = {}
    #add a note
    def add(self, fileName):
        self.notes[fileName] = pygame.mixer.Sound(fileName)
    #play a note
    def play(self, fileName):
        try:
            self.notes[fileName].play()
        except:
            print(fileName + 'not found!')
    
    def playRandom(self):
        index = random.randint(0, len(self.notes)-1)
        note = list(self.notes.values())[index]
        note.play()

# main function 

def main():
    global gShowPlot

    parser = argparse.ArgumentParser(description="Generating sounds with karplus strong algorithm")

    parser.add_argument('--display',action='store_true',required=False)
    parser.add_argument('--play',action='store_true',required=False)
    parser.add_argument('--piano',action='store_true',required=False)
    args = parser.parse_args()

    if args.display:
        gShowPlot = True
        plt.ion()
    
    nplayer = NotePlayer()
    print('creating notes............')
    for name, freq in list(pmNotes.items()):
        fileName = name + '.wav'
        if not os.path.exists(fileName) or args.display:
            data = generateNote(freq)
            print('creating' + fileName + '.....')
            writeWAVE(fileName, data)
        else:
            print('fileName already created. skipping...')
        
        nplayer.add(name + '.wav')

        if args.display:
            nplayer.play(name + '.wav')
            time.sleep(4)
    
    if args.play:
        while True:
            try:
                nplayer.playRandom()
                rest = np.random.choice([1,2,4,8], 1, p=[0.15,0.7,0.1,0.05])
                time.sleep(0.25*rest[0])
            except KeyboardInterrupt:
                exit()
    if args.piano:
        while True:
            for event in pygame.event.get():
                if (event.type == pygame.KEYUP):
                    print("key pressed")
                    nplayer.playRandom()
                    time.sleep(0.5)

if __name__ == '__main__':
    main()