Oscilloscope from File

oscilattor_player.py

'''
Jupyter Notebook code to generate a stream of matplotlib canvas plots
based on PyAudio data for a wav file.


original source https://stackoverflow.com/a/6951154/2223106
Also need to brew install portaudio on OSX or in an ENV perhaps
pip install --global-option='build_ext' --global-option='-I/usr/local/include' --global-option='-L/usr/local/lib' pyaudio

# ffmpeg -i song.mp3 -acodec pcm_u8 -ar 22050 song.wav
'''
import pyaudio
import wave
import sys
import struct
import numpy as np
import matplotlib.pyplot as plt

%matplotlib tk

class AudioFile:
    chunk = 1024 * 4

    def __init__(self, file):
        """ Init audio stream """ 
        self.wf = wave.open(file, 'rb')
        self.p = pyaudio.PyAudio()
        fig, ax = plt.subplots()
        self.fig = fig
        self.ax = ax
        self.x = np.arange(0, 2 * self.chunk, 2)
        self.line, = ax.plot(self.x, np.random.rand(self.chunk))
        self.ax.set_ylim(-255, 255)
        self.ax.set_xlim(0, self.chunk)
        self.stream = self.p.open(
            format = self.p.get_format_from_width(self.wf.getsampwidth()),
            channels = self.wf.getnchannels(),
            rate = self.wf.getframerate(),
            output = True,
            frames_per_buffer=self.chunk
        )

    def play(self):
        """ Play entire file """
        data = self.wf.readframes(self.chunk)
        while data != '':
            self.stream.write(data)
            data = self.wf.readframes(self.chunk)
            data_int = np.array(struct.unpack(str(2 * self.chunk) + 'B', data), dtype='b')[::2] + 127
            self.line.set_ydata(data_int)
            self.fig.canvas.draw()
            self.fig.canvas.flush_events()
            
    def close(self):
        """ Graceful shutdown """ 
        self.stream.close()
        self.p.terminate()

# Usage example for pyaudio
a = AudioFile("BenchBendsTheSound.wav")
a.play()
a.close()