Whitenoise generating snippet

whitenoise.py

import threading
import random
import Queue
import pyaudio
import numpy as np

SAMPLE_RATE = 44100
DURATION = 0.5

class WhitenoiseSound(threading.Thread):
    def __init__(self, freq_q, init_freq=10):
        super(WhitenoiseSound, self).__init__()
        self.freq = init_freq
        self.freq_q = freq_q
        self.stop_request = threading.Event()

        self.pya = pyaudio.PyAudio()

        self.stream = self.pya.open(format=pyaudio.paFloat32,
                                    channels=1,
                                    rate=SAMPLE_RATE,
                                    output=True,
                                    frames_per_buffer=int(SAMPLE_RATE*DURATION*0.5),
                                    stream_callback=self.callback)

    def run(self):
        while not self.stop_request.isSet():
            try:
                self.freq = self.freq_q.get(0.1)
            except Queue.Empty:
                pass
        self.stream.stop_stream()
        self.stream.close()
        self.pya.terminate()

    def callback(self, _in_data, frame_count, _time_info, _status):
        samples = np.zeros(frame_count).astype(np.float32)
        spacing = (frame_count / self.freq) * 3
        last_idx = 0
        for idx in range(frame_count):
            chance = ((idx - last_idx) % spacing) + 0.1
            if random.randrange(11) / 10.0 < chance:
                samples[idx] = random.randrange(11) / 10.0
                last_idx = idx
        return samples, pyaudio.paContinue

    def join(self, timeout=None):
        self.stop_request.set()
        super(WhitenoiseSound, self).join(timeout)

if __name__ == "__main__":
    freq_q = Queue.Queue()
    gcs = WhitenoiseSound(freq_q)
    gcs.start()