| /* |
| * Copyright (c) 2016 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/level_controller/noise_spectrum_estimator.h" |
| |
| #include <string.h> |
| #include <algorithm> |
| |
| #include "webrtc/api/array_view.h" |
| #include "webrtc/modules/audio_processing/logging/apm_data_dumper.h" |
| #include "webrtc/rtc_base/arraysize.h" |
| |
| namespace webrtc { |
| namespace { |
| constexpr float kMinNoisePower = 100.f; |
| } // namespace |
| |
| NoiseSpectrumEstimator::NoiseSpectrumEstimator(ApmDataDumper* data_dumper) |
| : data_dumper_(data_dumper) { |
| Initialize(); |
| } |
| |
| void NoiseSpectrumEstimator::Initialize() { |
| std::fill(noise_spectrum_, noise_spectrum_ + arraysize(noise_spectrum_), |
| kMinNoisePower); |
| } |
| |
| void NoiseSpectrumEstimator::Update(rtc::ArrayView<const float> spectrum, |
| bool first_update) { |
| RTC_DCHECK_EQ(65, spectrum.size()); |
| |
| if (first_update) { |
| // Initialize the noise spectral estimate with the signal spectrum. |
| std::copy(spectrum.data(), spectrum.data() + spectrum.size(), |
| noise_spectrum_); |
| } else { |
| // Smoothly update the noise spectral estimate towards the signal spectrum |
| // such that the magnitude of the updates are limited. |
| for (size_t k = 0; k < spectrum.size(); ++k) { |
| if (noise_spectrum_[k] < spectrum[k]) { |
| noise_spectrum_[k] = std::min( |
| 1.01f * noise_spectrum_[k], |
| noise_spectrum_[k] + 0.05f * (spectrum[k] - noise_spectrum_[k])); |
| } else { |
| noise_spectrum_[k] = std::max( |
| 0.99f * noise_spectrum_[k], |
| noise_spectrum_[k] + 0.05f * (spectrum[k] - noise_spectrum_[k])); |
| } |
| } |
| } |
| |
| // Ensure that the noise spectal estimate does not become too low. |
| for (auto& v : noise_spectrum_) { |
| v = std::max(v, kMinNoisePower); |
| } |
| |
| data_dumper_->DumpRaw("lc_noise_spectrum", 65, noise_spectrum_); |
| data_dumper_->DumpRaw("lc_signal_spectrum", spectrum); |
| } |
| |
| } // namespace webrtc |