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# Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
#
# Use of this source code is governed by a BSD-style license
# that can be found in the LICENSE file in the root of the source
# tree. An additional intellectual property rights grant can be found
# in the file PATENTS. All contributing project authors may
# be found in the AUTHORS file in the root of the source tree.
"""Unit tests for the signal_processing module.
"""
import unittest
import numpy as np
import pydub
from . import exceptions
from . import signal_processing
class TestSignalProcessing(unittest.TestCase):
"""Unit tests for the signal_processing module.
"""
def testMixSignals(self):
# Generate a template signal with which white noise can be generated.
silence = pydub.AudioSegment.silent(duration=1000, frame_rate=48000)
# Generate two distinct AudioSegment instances with 1 second of white noise.
signal = signal_processing.SignalProcessingUtils.GenerateWhiteNoise(
silence)
noise = signal_processing.SignalProcessingUtils.GenerateWhiteNoise(
silence)
# Extract samples.
signal_samples = signal.get_array_of_samples()
noise_samples = noise.get_array_of_samples()
# Test target SNR -Inf (noise expected).
mix_neg_inf = signal_processing.SignalProcessingUtils.MixSignals(
signal, noise, -np.Inf)
self.assertTrue(len(noise), len(mix_neg_inf)) # Check duration.
mix_neg_inf_samples = mix_neg_inf.get_array_of_samples()
self.assertTrue( # Check samples.
all([x == y for x, y in zip(noise_samples, mix_neg_inf_samples)]))
# Test target SNR 0.0 (different data expected).
mix_0 = signal_processing.SignalProcessingUtils.MixSignals(
signal, noise, 0.0)
self.assertTrue(len(signal), len(mix_0)) # Check duration.
self.assertTrue(len(noise), len(mix_0))
mix_0_samples = mix_0.get_array_of_samples()
self.assertTrue(
any([x != y for x, y in zip(signal_samples, mix_0_samples)]))
self.assertTrue(
any([x != y for x, y in zip(noise_samples, mix_0_samples)]))
# Test target SNR +Inf (signal expected).
mix_pos_inf = signal_processing.SignalProcessingUtils.MixSignals(
signal, noise, np.Inf)
self.assertTrue(len(signal), len(mix_pos_inf)) # Check duration.
mix_pos_inf_samples = mix_pos_inf.get_array_of_samples()
self.assertTrue( # Check samples.
all([x == y for x, y in zip(signal_samples, mix_pos_inf_samples)]))
def testMixSignalsMinInfPower(self):
silence = pydub.AudioSegment.silent(duration=1000, frame_rate=48000)
signal = signal_processing.SignalProcessingUtils.GenerateWhiteNoise(
silence)
with self.assertRaises(exceptions.SignalProcessingException):
_ = signal_processing.SignalProcessingUtils.MixSignals(
signal, silence, 0.0)
with self.assertRaises(exceptions.SignalProcessingException):
_ = signal_processing.SignalProcessingUtils.MixSignals(
silence, signal, 0.0)
def testMixSignalNoiseDifferentLengths(self):
# Test signals.
shorter = signal_processing.SignalProcessingUtils.GenerateWhiteNoise(
pydub.AudioSegment.silent(duration=1000, frame_rate=8000))
longer = signal_processing.SignalProcessingUtils.GenerateWhiteNoise(
pydub.AudioSegment.silent(duration=2000, frame_rate=8000))
# When the signal is shorter than the noise, the mix length always equals
# that of the signal regardless of whether padding is applied.
# No noise padding, length of signal less than that of noise.
mix = signal_processing.SignalProcessingUtils.MixSignals(
signal=shorter,
noise=longer,
pad_noise=signal_processing.SignalProcessingUtils.MixPadding.
NO_PADDING)
self.assertEqual(len(shorter), len(mix))
# With noise padding, length of signal less than that of noise.
mix = signal_processing.SignalProcessingUtils.MixSignals(
signal=shorter,
noise=longer,
pad_noise=signal_processing.SignalProcessingUtils.MixPadding.
ZERO_PADDING)
self.assertEqual(len(shorter), len(mix))
# When the signal is longer than the noise, the mix length depends on
# whether padding is applied.
# No noise padding, length of signal greater than that of noise.
mix = signal_processing.SignalProcessingUtils.MixSignals(
signal=longer,
noise=shorter,
pad_noise=signal_processing.SignalProcessingUtils.MixPadding.
NO_PADDING)
self.assertEqual(len(shorter), len(mix))
# With noise padding, length of signal greater than that of noise.
mix = signal_processing.SignalProcessingUtils.MixSignals(
signal=longer,
noise=shorter,
pad_noise=signal_processing.SignalProcessingUtils.MixPadding.
ZERO_PADDING)
self.assertEqual(len(longer), len(mix))
def testMixSignalNoisePaddingTypes(self):
# Test signals.
shorter = signal_processing.SignalProcessingUtils.GenerateWhiteNoise(
pydub.AudioSegment.silent(duration=1000, frame_rate=8000))
longer = signal_processing.SignalProcessingUtils.GeneratePureTone(
pydub.AudioSegment.silent(duration=2000, frame_rate=8000), 440.0)
# Zero padding: expect pure tone only in 1-2s.
mix_zero_pad = signal_processing.SignalProcessingUtils.MixSignals(
signal=longer,
noise=shorter,
target_snr=-6,
pad_noise=signal_processing.SignalProcessingUtils.MixPadding.
ZERO_PADDING)
# Loop: expect pure tone plus noise in 1-2s.
mix_loop = signal_processing.SignalProcessingUtils.MixSignals(
signal=longer,
noise=shorter,
target_snr=-6,
pad_noise=signal_processing.SignalProcessingUtils.MixPadding.LOOP)
def Energy(signal):
samples = signal_processing.SignalProcessingUtils.AudioSegmentToRawData(
signal).astype(np.float32)
return np.sum(samples * samples)
e_mix_zero_pad = Energy(mix_zero_pad[-1000:])
e_mix_loop = Energy(mix_loop[-1000:])
self.assertLess(0, e_mix_zero_pad)
self.assertLess(e_mix_zero_pad, e_mix_loop)
def testMixSignalSnr(self):
# Test signals.
tone_low = signal_processing.SignalProcessingUtils.GeneratePureTone(
pydub.AudioSegment.silent(duration=64, frame_rate=8000), 250.0)
tone_high = signal_processing.SignalProcessingUtils.GeneratePureTone(
pydub.AudioSegment.silent(duration=64, frame_rate=8000), 3000.0)
def ToneAmplitudes(mix):
"""Returns the amplitude of the coefficients #16 and #192, which
correspond to the tones at 250 and 3k Hz respectively."""
mix_fft = np.absolute(
signal_processing.SignalProcessingUtils.Fft(mix))
return mix_fft[16], mix_fft[192]
mix = signal_processing.SignalProcessingUtils.MixSignals(
signal=tone_low, noise=tone_high, target_snr=-6)
ampl_low, ampl_high = ToneAmplitudes(mix)
self.assertLess(ampl_low, ampl_high)
mix = signal_processing.SignalProcessingUtils.MixSignals(
signal=tone_high, noise=tone_low, target_snr=-6)
ampl_low, ampl_high = ToneAmplitudes(mix)
self.assertLess(ampl_high, ampl_low)
mix = signal_processing.SignalProcessingUtils.MixSignals(
signal=tone_low, noise=tone_high, target_snr=6)
ampl_low, ampl_high = ToneAmplitudes(mix)
self.assertLess(ampl_high, ampl_low)
mix = signal_processing.SignalProcessingUtils.MixSignals(
signal=tone_high, noise=tone_low, target_snr=6)
ampl_low, ampl_high = ToneAmplitudes(mix)
self.assertLess(ampl_low, ampl_high)
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