# 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)