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

webrtc/modules/audio_processing/aec3/decimator_by_4_unittest.cc

Index: webrtc/modules/audio_processing/aec3/decimator_by_4_unittest.cc
diff --git a/webrtc/modules/audio_processing/aec3/decimator_by_4_unittest.cc b/webrtc/modules/audio_processing/aec3/decimator_by_4_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a7699ba64f18cc22528f797b784b0d28d7c92f11
--- /dev/null
+++ b/webrtc/modules/audio_processing/aec3/decimator_by_4_unittest.cc
@@ -0,0 +1,127 @@
+/*
+ *  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/decimator_by_4.h"
+
+#include <math.h>
+#include <algorithm>
+#include <array>
+#include <numeric>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "webrtc/modules/audio_processing/aec3/aec3_constants.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();
+}
+
+constexpr float kPi = 3.141592f;
+constexpr size_t kNumStartupBlocks = 50;
+constexpr size_t kNumBlocks = 1000;
+
+void ProduceDecimatedSinusoidalOutputPower(int sample_rate_hz,
+                                           float sinusoidal_frequency_hz,
+                                           float* input_power,
+                                           float* output_power) {
+  float input[kBlockSize * kNumBlocks];
+
+  // Produce a sinusoid of the specified frequency.
+  for (size_t k = 0; k < kBlockSize * kNumBlocks; ++k) {
+    input[k] =
+        32767.f * sin(2.f * kPi * sinusoidal_frequency_hz * k / sample_rate_hz);
+  }
+
+  DecimatorBy4 decimator;
+  std::array<float, kSubBlockSize * kNumBlocks> output;
+
+  for (size_t k = 0; k < kNumBlocks; ++k) {
+    std::array<float, kSubBlockSize> sub_block;
+
+    decimator.Decimate(
+        rtc::ArrayView<const float>(&input[k * kBlockSize], kBlockSize),
+        &sub_block);
+
+    std::copy(sub_block.begin(), sub_block.end(),
+              output.begin() + k * kSubBlockSize);
+  }
+
+  ASSERT_GT(kNumBlocks, kNumStartupBlocks);
+  rtc::ArrayView<const float> input_to_evaluate(
+      &input[kNumStartupBlocks * kBlockSize],
+      (kNumBlocks - kNumStartupBlocks) * kBlockSize);
+  rtc::ArrayView<const float> output_to_evaluate(
+      &output[kNumStartupBlocks * kSubBlockSize],
+      (kNumBlocks - kNumStartupBlocks) * kSubBlockSize);
+  *input_power =
+      std::inner_product(input_to_evaluate.begin(), input_to_evaluate.end(),
+                         input_to_evaluate.begin(), 0.f) /
+      input_to_evaluate.size();
+  *output_power =
+      std::inner_product(output_to_evaluate.begin(), output_to_evaluate.end(),
+                         output_to_evaluate.begin(), 0.f) /
+      output_to_evaluate.size();
+}
+
+}  // namespace
+
+// Verifies that there is little aliasing from upper frequencies in the
+// downsampling.
+TEST(DecimatorBy4, NoLeakageFromUpperFrequencies) {
+  float input_power;
+  float output_power;
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    ProduceDebugText(rate);
+    ProduceDecimatedSinusoidalOutputPower(rate, 3.f / 8.f * rate, &input_power,
+                                          &output_power);
+    EXPECT_GT(0.0001f * input_power, output_power);
+  }
+}
+
+// Verifies that the impact of low-frequency content is small during the
+// downsampling.
+TEST(DecimatorBy4, NoImpactOnLowerFrequencies) {
+  float input_power;
+  float output_power;
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    ProduceDebugText(rate);
+    ProduceDecimatedSinusoidalOutputPower(rate, 200.f, &input_power,
+                                          &output_power);
+    EXPECT_LT(0.7f * input_power, output_power);
+  }
+}
+
+#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
+// Verifies the check for the input size.
+TEST(DecimatorBy4, WrongInputSize) {
+  DecimatorBy4 decimator;
+  std::vector<float> x(std::vector<float>(kBlockSize - 1, 0.f));
+  std::array<float, kSubBlockSize> x_downsampled;
+  EXPECT_DEATH(decimator.Decimate(x, &x_downsampled), "");
+}
+
+// Verifies the check for non-null output parameter.
+TEST(DecimatorBy4, NullOutput) {
+  DecimatorBy4 decimator;
+  std::vector<float> x(std::vector<float>(kBlockSize, 0.f));
+  EXPECT_DEATH(decimator.Decimate(x, nullptr), "");
+}
+
+#endif
+
+}  // namespace webrtc