How to generate audio from a numpy array?

python audio numpy matplotlib

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Solution 1

You can use the write function from scipy.io.wavfile to create a wav file which you can then play however you wish. Note that the array must be integers, so if you have floats, you might want to scale them appropriately:

import numpy as np
from scipy.io.wavfile import write

data = np.random.uniform(-1,1,44100) # 44100 random samples between -1 and 1
scaled = np.int16(data/np.max(np.abs(data)) * 32767)
write('test.wav', 44100, scaled)

If you want Python to actually play audio, then this page provides an overview of some of the packages/modules.

Solution 2

For the people coming here in 2016 scikits.audiolab doesn't really seem to work anymore. I was able to get a solution using sounddevice.

import numpy as np
import sounddevice as sd

fs = 44100
data = np.random.uniform(-1, 1, fs)
sd.play(data, fs)

Solution 3

in Jupyter the best option is:

from IPython.display import Audio
wave_audio = numpy.sin(numpy.linspace(0, 3000, 20000))
Audio(wave_audio, rate=20000)

Solution 4

I had some problems using scikit.audiolabs, so I looked for some other options for this task. I came up with sounddevice, which seems a lot more up-to-date. I have not checked if it works with Python 3.

A simple way to perform what you want is this:

import numpy as np
import sounddevice as sd

sd.default.samplerate = 44100

time = 2.0
frequency = 440

# Generate time of samples between 0 and two seconds
samples = np.arange(44100 * time) / 44100.0
# Recall that a sinusoidal wave of frequency f has formula w(t) = A*sin(2*pi*f*t)
wave = 10000 * np.sin(2 * np.pi * frequency * samples)
# Convert it to wav format (16 bits)
wav_wave = np.array(wave, dtype=np.int16)

sd.play(wav_wave, blocking=True)

Solution 5

In addition, you could try scikits.audiolab. It features file IO and the ability to 'play' arrays. Arrays don't have to be integers. To mimick dbaupp's example:

import numpy as np
import scikits.audiolab

data = np.random.uniform(-1,1,44100)
# write array to file:
scikits.audiolab.wavwrite(data, 'test.wav', fs=44100, enc='pcm16')
# play the array:
scikits.audiolab.play(data, fs=44100)

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