1 files changed, 98 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/agc2/noise_level_estimator_unittest.cc b/third_party/libwebrtc/modules/audio_processing/agc2/noise_level_estimator_unittest.cc
new file mode 100644
index 0000000000..8168c5a229
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/agc2/noise_level_estimator_unittest.cc
@@ -0,0 +1,98 @@
+/*
+ *  Copyright (c) 2018 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 "modules/audio_processing/agc2/noise_level_estimator.h"
+
+#include <array>
+#include <cmath>
+#include <functional>
+#include <limits>
+
+#include "api/function_view.h"
+#include "modules/audio_processing/agc2/agc2_testing_common.h"
+#include "modules/audio_processing/agc2/vector_float_frame.h"
+#include "modules/audio_processing/logging/apm_data_dumper.h"
+#include "rtc_base/gunit.h"
+
+namespace webrtc {
+namespace {
+
+constexpr int kNumIterations = 200;
+constexpr int kFramesPerSecond = 100;
+
+// Runs the noise estimator on audio generated by 'sample_generator'
+// for kNumIterations. Returns the last noise level estimate.
+float RunEstimator(rtc::FunctionView<float()> sample_generator,
+                   NoiseLevelEstimator& estimator,
+                   int sample_rate_hz) {
+  const int samples_per_channel =
+      rtc::CheckedDivExact(sample_rate_hz, kFramesPerSecond);
+  VectorFloatFrame signal(1, samples_per_channel, 0.0f);
+  for (int i = 0; i < kNumIterations; ++i) {
+    AudioFrameView<float> frame_view = signal.float_frame_view();
+    for (int j = 0; j < samples_per_channel; ++j) {
+      frame_view.channel(0)[j] = sample_generator();
+    }
+    estimator.Analyze(frame_view);
+  }
+  return estimator.Analyze(signal.float_frame_view());
+}
+
+class NoiseEstimatorParametrization : public ::testing::TestWithParam<int> {
+ protected:
+  int sample_rate_hz() const { return GetParam(); }
+};
+
+// Checks that full scale white noise maps to about -5.5 dBFS.
+TEST_P(NoiseEstimatorParametrization, NoiseFloorEstimatorWithRandomNoise) {
+  ApmDataDumper data_dumper(0);
+  auto estimator = CreateNoiseFloorEstimator(&data_dumper);
+
+  test::WhiteNoiseGenerator gen(/*min_amplitude=*/test::kMinS16,
+                                /*max_amplitude=*/test::kMaxS16);
+  const float noise_level_dbfs =
+      RunEstimator(gen, *estimator, sample_rate_hz());
+  EXPECT_NEAR(noise_level_dbfs, -5.5f, 0.5f);
+}
+
+// Checks that a full scale sine wave maps to about -3 dBFS.
+TEST_P(NoiseEstimatorParametrization, NoiseFloorEstimatorWithSineTone) {
+  ApmDataDumper data_dumper(0);
+  auto estimator = CreateNoiseFloorEstimator(&data_dumper);
+
+  test::SineGenerator gen(/*amplitude=*/test::kMaxS16, /*frequency_hz=*/600.0f,
+                          sample_rate_hz());
+  const float noise_level_dbfs =
+      RunEstimator(gen, *estimator, sample_rate_hz());
+  EXPECT_NEAR(noise_level_dbfs, -3.0f, 0.1f);
+}
+
+// Check that sufficiently spaced periodic pulses do not raise the estimated
+// noise floor, which is determined by the amplitude of the non-pulse samples.
+TEST_P(NoiseEstimatorParametrization, NoiseFloorEstimatorWithPulseTone) {
+  ApmDataDumper data_dumper(0);
+  auto estimator = CreateNoiseFloorEstimator(&data_dumper);
+
+  constexpr float kNoPulseAmplitude = 10.0f;
+  test::PulseGenerator gen(/*pulse_amplitude=*/test::kMaxS16, kNoPulseAmplitude,
+                           /*frequency_hz=*/20.0f, sample_rate_hz());
+  const float noise_level_dbfs =
+      RunEstimator(gen, *estimator, sample_rate_hz());
+  const float expected_noise_floor_dbfs =
+      20.0f * std::log10f(kNoPulseAmplitude / test::kMaxS16);
+  EXPECT_NEAR(noise_level_dbfs, expected_noise_floor_dbfs, 0.5f);
+}
+
+INSTANTIATE_TEST_SUITE_P(GainController2NoiseEstimator,
+                         NoiseEstimatorParametrization,
+                         ::testing::Values(8000, 16000, 32000, 48000));
+
+}  // namespace
+}  // namespace webrtc