:orphan:

audio_ex
--------


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

.. raw:: html

  <video width="558" height="558" controls autoplay>
    <source src="../_static/examples/audio_ex.mov" type="video/mp4">
    <source src="../_static/examples/audio_ex.ogg" type="video/ogg">
  </video>

----

.. code-block:: python
    
    
    
    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)