ostinato.py

#!/usr/bin/env python

import numpy as np
import pyaudio
import scipy.io.wavfile as wav
import random
import time
import gc

from numpy import zeros, mat, matrix, sqrt, sin, arange, pi, exp, cos, array, dot, max, abs, int16, eye

signal = np.ndarray(shape=(0,2))

fs,A = wav.read("A.wav") # reading
fs,Bm = wav.read("Bm.wav") # reading
fs,D = wav.read("D.wav") # reading
fs,G = wav.read("G.wav") # reading

sigs = A, Bm, D, G
speed = 33000;

signal = np.vstack(( signal, sigs[random.randint(0,3)] ));
readposition = 0;
writeposition = 0;

def callback(in_data, frame_count, time_info, status):
	global signal
	global readposition
	data = (0.00001 * signal[readposition:readposition+frame_count]).astype(np.float32).tostring()
	readposition = readposition+frame_count;
	return (data, pyaudio.paContinue)

p = pyaudio.PyAudio()
stream = p.open(format=pyaudio.paFloat32,
				channels=2,
				rate=fs,
				output=True,
				stream_callback=callback)

while stream.is_active():
	if(len(signal) - writeposition < 6*fs):
		print("Allocating")
		signal = np.vstack(( signal, np.zeros((8*fs,2)) ));
	if(writeposition - readposition < 2*fs):
		print("Recording")
		sample = sigs[random.randint(0,3)]
		for j in range(0, 4):
			offset = writeposition + j*speed;
			if j == 0:
				signal[offset:offset+len(sample)] += sample
			else:
				signal[offset:offset+len(sample)] += sample/2
		writeposition += (j+1)*speed
	if(readposition > 5*fs):
		print("Freeing")
		signal = signal[5*fs:];
		readposition -= 5*fs;
		writeposition -= 5*fs;
	time.sleep(0.2)
	gc.collect()

print("Stream finished")