Adding full initial version of delay estimation functionality in echo canceller 3

webrtc/modules/audio_processing/aec3/echo_path_delay_estimator_unittest.cc

 /*
  *  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.
  */
 
 #include "webrtc/modules/audio_processing/aec3/echo_path_delay_estimator.h"
 
+#include <algorithm>
 #include <sstream>
 #include <string>
 
+#include "webrtc/base/random.h"
 #include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
 #include "webrtc/modules/audio_processing/logging/apm_data_dumper.h"
+#include "webrtc/modules/audio_processing/test/echo_canceller_test_tools.h"
 #include "webrtc/test/gtest.h"
 
 namespace webrtc {
 namespace {
 
 std::string ProduceDebugText(int sample_rate_hz) {
   std::ostringstream ss;
   ss << "Sample rate: " << sample_rate_hz;
   return ss.str();
 }
 
+std::string ProduceDebugText(int sample_rate_hz, size_t delay) {
+  std::ostringstream ss(ProduceDebugText(sample_rate_hz));
+  ss << ", Delay: " << delay;
+  return ss.str();
+}
+
 }  // namespace
 
 // Verifies that the basic API calls work.
 TEST(EchoPathDelayEstimator, BasicApiCalls) {
   for (auto rate : {8000, 16000, 32000, 48000}) {
     ProduceDebugText(rate);
     ApmDataDumper data_dumper(0);
     EchoPathDelayEstimator estimator(&data_dumper, rate);
     std::vector<float> render(std::vector<float>(kBlockSize, 0.f));
     std::vector<float> capture(std::vector<float>(kBlockSize, 0.f));
     for (size_t k = 0; k < 100; ++k) {
       estimator.EstimateDelay(render, capture);
     }
   }
 }
 
+// Verifies that the delay estimator produces correct delay for artificially
+// delayed signals.
+TEST(EchoPathDelayEstimator, DelayEstimation) {
+  Random random_generator(42U);
+  std::vector<float> render(kBlockSize, 0.f);
+  std::vector<float> capture(kBlockSize, 0.f);
+  ApmDataDumper data_dumper(0);
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    for (size_t delay_samples : {0, 64, 150, 200, 800, 4000}) {
+      SCOPED_TRACE(ProduceDebugText(rate, delay_samples));
+      DelayBuffer<float> signal_delay_buffer(delay_samples);
+      EchoPathDelayEstimator estimator(&data_dumper, rate);
+
+      rtc::Optional<size_t> estimated_delay_samples;
+      for (size_t k = 0; k < (100 + delay_samples / kBlockSize); ++k) {
+        RandomizeSampleVector(&random_generator, render);
+        signal_delay_buffer.Delay(render, capture);
+        estimated_delay_samples = estimator.EstimateDelay(render, capture);
+      }
+      if (estimated_delay_samples) {
+        EXPECT_NEAR(delay_samples, *estimated_delay_samples, 4);

[aleloi, 2017/02/03 15:46:48]

Is the 4 here because of the down sampling factor?

[peah-webrtc, 2017/02/06 11:25:39]

Yes, that is the reason. 
I added a comment to clarify this.

Done.

+      } else {
+        ADD_FAILURE();
+      }
+    }
+  }
+}
+
+// Verifies that the delay estimator does not produce delay estimates too
+// quickly.
+TEST(EchoPathDelayEstimator, NoInitialDelayestimates) {
+  Random random_generator(42U);
+  std::vector<float> render(kBlockSize, 0.f);
+  std::vector<float> capture(kBlockSize, 0.f);
+  ApmDataDumper data_dumper(0);
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    SCOPED_TRACE(ProduceDebugText(rate));
+    EchoPathDelayEstimator estimator(&data_dumper, rate);
+    for (size_t k = 0; k < 19; ++k) {
+      RandomizeSampleVector(&random_generator, render);
+      std::copy(render.begin(), render.end(), capture.begin());
+      EXPECT_FALSE(estimator.EstimateDelay(render, capture));
+    }
+  }
+}
+
+// Verifies that the delay estimator does not produce delay estimates for render
+// signals of low level.
+TEST(EchoPathDelayEstimator, NoDelayEstimatesForLowLevelRenderSignals) {
+  Random random_generator(42U);
+  std::vector<float> render(kBlockSize, 0.f);
+  std::vector<float> capture(kBlockSize, 0.f);
+  ApmDataDumper data_dumper(0);
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    SCOPED_TRACE(ProduceDebugText(rate));
+    EchoPathDelayEstimator estimator(&data_dumper, rate);
+    for (size_t k = 0; k < 100; ++k) {
+      RandomizeSampleVector(&random_generator, render);
+      for (auto& render_k : render) {
+        render_k *= 100.f / 32767.f;
+      }
+      std::copy(render.begin(), render.end(), capture.begin());
+      EXPECT_FALSE(estimator.EstimateDelay(render, capture));
+    }
+  }
+}
+
+// Verifies that the delay estimator does not produce delay estimates for
+// uncorrelated signals.
+TEST(EchoPathDelayEstimator, NoDelayEstimatesForUncorrelatedSignals) {
+  Random random_generator(42U);
+  std::vector<float> render(kBlockSize, 0.f);
+  std::vector<float> capture(kBlockSize, 0.f);
+  ApmDataDumper data_dumper(0);
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    SCOPED_TRACE(ProduceDebugText(rate));
+    EchoPathDelayEstimator estimator(&data_dumper, rate);
+    for (size_t k = 0; k < 100; ++k) {
+      RandomizeSampleVector(&random_generator, render);
+      RandomizeSampleVector(&random_generator, capture);
+      EXPECT_FALSE(estimator.EstimateDelay(render, capture));
+    }
+  }
+}
+
 #if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
 
 // Verifies the check for correct sample rate.
 TEST(EchoPathDelayEstimator, WrongSampleRate) {
   ApmDataDumper data_dumper(0);
-  EXPECT_DEATH(EchoPathDelayEstimator remover(&data_dumper, 8001), "");
+  EXPECT_DEATH(EchoPathDelayEstimator(&data_dumper, 8001), "");
 }
 
 // Verifies the check for the render blocksize.
 TEST(EchoPathDelayEstimator, WrongRenderBlockSize) {
   for (auto rate : {8000, 16000, 32000, 48000}) {
     ProduceDebugText(rate);
     ApmDataDumper data_dumper(0);
     EchoPathDelayEstimator estimator(&data_dumper, rate);
     std::vector<float> render(std::vector<float>(kBlockSize - 1, 0.f));
     std::vector<float> capture(std::vector<float>(kBlockSize, 0.f));
@@ skipping 14 matching lines @@
 }
 
 // Verifies the check for non-null data dumper.
 TEST(EchoPathDelayEstimator, NullDataDumper) {
   EXPECT_DEATH(EchoPathDelayEstimator(nullptr, 8000), "");
 }
 
 #endif
 
 }  // namespace webrtc