import numpy as np

import matplotlib.pyplot as plt

from scipy.io import wavfile

# Read the input file

sampling_freq, audio = wavfile.read('input_read.wav')

# Print the params

print '\nShape:', audio.shape

print 'Datatype:', audio.dtype

print 'Duration:', round(audio.shape[0] / float(sampling_freq), 3), 'seconds'

# Normalize the values

audio = audio / (2.**15)

# Extract first 30 values for plotting

audio = audio[:30]

# Build the time axis

x_values = np.arange(0, len(audio), 1) / float(sampling_freq)

# Convert to seconds

x_values *= 1000

# Plotting the chopped audio signal

plt.plot(x_values, audio, color='black')

plt.xlabel('Time (ms)')

plt.ylabel('Amplitude')

plt.title('Audio signal')

plt.show()