audio_ex

Play an audio file and display signal and power spectrum in realtime

---

import os
import wave
import numpy as np
import pyaudio
import gr

SAMPLES = 2048

wf = wave.open(os.path.join(os.path.dirname(os.path.realpath(__file__)),
                            'Monty_Python.wav'), 'rb')
pa = pyaudio.PyAudio()
stream = pa.open(
    format=pa.get_format_from_width(wf.getsampwidth()),
    channels=wf.getnchannels(),
    rate=wf.getframerate(),
    output=True
)

gr.setwindow(0, SAMPLES, -30000, 30000)
gr.setviewport(0.05, 0.95, 0.05, 0.95)
gr.setlinecolorind(218)
gr.setfillintstyle(1)
gr.setfillcolorind(208)

data = wf.readframes(SAMPLES)
while data != '' and len(data) == SAMPLES * wf.getsampwidth():
    stream.write(data)
    amplitudes = np.frombuffer(data, dtype=np.short)
    power = abs(np.fft.fft(amplitudes / 512.0))[:SAMPLES // 2:2] - 30000

    gr.clearws()
    gr.fillrect(0, SAMPLES, -30000, 30000)
    gr.grid(40, 1200, 0, 0, 5, 5)
    gr.polyline(np.arange(0, SAMPLES, 4), amplitudes[0::4])
    gr.polyline(np.arange(0, SAMPLES, 4), power)
    gr.updatews()

    data = wf.readframes(SAMPLES)