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/*
* 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
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