Total Harmonic Distorsion plus noise (THD+n) score in APM-QA.

modules/audio_processing/test/py_quality_assessment/quality_assessment/eval_scores_unittest.py

 # 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 eval_scores module.
 """
@@ skipping 34 matching lines @@
     self._fake_tested_signal_filepath = os.path.join(
         self._output_path, 'fake_test.wav')
     signal_processing.SignalProcessingUtils.SaveWav(
         self._fake_tested_signal_filepath, fake_tested_signal)
 
   def tearDown(self):
     """Recursively delete temporary folder."""
     shutil.rmtree(self._output_path)
 
   def testRegisteredClasses(self):
+    # Evaluation score names to exclude (tested separately).
+    exceptions = ['thd']
+
     # Preliminary check.
     self.assertTrue(os.path.exists(self._output_path))
 
     # Check that there is at least one registered evaluation score worker.
     registered_classes = eval_scores.EvaluationScore.REGISTERED_CLASSES
     self.assertIsInstance(registered_classes, dict)
     self.assertGreater(len(registered_classes), 0)
 
     # Instance evaluation score workers factory with fake dependencies.
     eval_score_workers_factory = (
         eval_scores_factory.EvaluationScoreWorkerFactory(
             score_filename_prefix='scores-',
             polqa_tool_bin_path=os.path.join(
                 os.path.dirname(os.path.abspath(__file__)), 'fake_polqa')))
 
     # Try each registered evaluation score worker.
     for eval_score_name in registered_classes:
+      if eval_score_name in exceptions:
+        continue
+
       # Instance evaluation score worker.
       eval_score_worker = eval_score_workers_factory.GetInstance(
           registered_classes[eval_score_name])
 
-      # Set reference and test, then run.
+      # Set fake input metadata and reference and test file paths, then run.
       eval_score_worker.SetReferenceSignalFilepath(
           self._fake_reference_signal_filepath)
       eval_score_worker.SetTestedSignalFilepath(
           self._fake_tested_signal_filepath)
       eval_score_worker.Run(self._output_path)
 
       # Check output.
       score = data_access.ScoreFile.Load(eval_score_worker.output_filepath)
       self.assertTrue(isinstance(score, float))
+
+  def testTotalHarmonicDistorsionScore(self):
+    # Init.
+    pure_tone_freq = 5000.0
+    eval_score_worker = eval_scores.TotalHarmonicDistorsionScore('scores-')
+    eval_score_worker.SetInputSignalMetadata({
+        'signal': 'pure_tone',
+        'frequency': pure_tone_freq,
+        'test_data_gen_name': 'identity',
+        'test_data_gen_config': 'default',
+    })
+    template = pydub.AudioSegment.silent(duration=1000, frame_rate=48000)
+
+    # Create 3 test signals: pure tone, pure tone + white noise, white noise
+    # only.
+    pure_tone = signal_processing.SignalProcessingUtils.GeneratePureTone(
+        template, pure_tone_freq)
+    white_noise = signal_processing.SignalProcessingUtils.GenerateWhiteNoise(
+        template)
+    noisy_tone = signal_processing.SignalProcessingUtils.MixSignals(
+        pure_tone, white_noise)
+
+    # Compute scores for increasingly distorted pure tone signals.
+    scores = [None, None, None]
+    for index, tested_signal in enumerate([pure_tone, noisy_tone, white_noise]):
+      # Save signal.
+      tmp_filepath = os.path.join(self._output_path, 'tmp_thd.wav')
+      signal_processing.SignalProcessingUtils.SaveWav(
+          tmp_filepath, tested_signal)
+
+      # Compute score.
+      eval_score_worker.SetTestedSignalFilepath(tmp_filepath)
+      eval_score_worker.Run(self._output_path)
+      scores[index] = eval_score_worker.score
+
+      # Remove output file to avoid caching.
+      os.remove(eval_score_worker.output_filepath)
+
+    # Validate scores (lowest score with a pure tone).
+    self.assertTrue(all([scores[i + 1] > scores[i] for i in range(2)]))