Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
       3             :  *
       4             :  *  Use of this source code is governed by a BSD-style license
       5             :  *  that can be found in the LICENSE file in the root of the source
       6             :  *  tree. An additional intellectual property rights grant can be found
       7             :  *  in the file PATENTS.  All contributing project authors may
       8             :  *  be found in the AUTHORS file in the root of the source tree.
       9             :  */
      10             : 
      11             : #include "webrtc/modules/audio_processing/level_controller/noise_spectrum_estimator.h"
      12             : 
      13             : #include <string.h>
      14             : #include <algorithm>
      15             : 
      16             : #include "webrtc/base/array_view.h"
      17             : #include "webrtc/base/arraysize.h"
      18             : #include "webrtc/modules/audio_processing/logging/apm_data_dumper.h"
      19             : 
      20             : namespace webrtc {
      21             : namespace {
      22             : float kMinNoisePower = 100.f;
      23             : }  // namespace
      24             : 
      25           0 : NoiseSpectrumEstimator::NoiseSpectrumEstimator(ApmDataDumper* data_dumper)
      26           0 :     : data_dumper_(data_dumper) {
      27           0 :   Initialize();
      28           0 : }
      29             : 
      30           0 : void NoiseSpectrumEstimator::Initialize() {
      31           0 :   std::fill(noise_spectrum_, noise_spectrum_ + arraysize(noise_spectrum_),
      32           0 :             kMinNoisePower);
      33           0 : }
      34             : 
      35           0 : void NoiseSpectrumEstimator::Update(rtc::ArrayView<const float> spectrum,
      36             :                                     bool first_update) {
      37           0 :   RTC_DCHECK_EQ(65, spectrum.size());
      38             : 
      39           0 :   if (first_update) {
      40             :     // Initialize the noise spectral estimate with the signal spectrum.
      41           0 :     std::copy(spectrum.data(), spectrum.data() + spectrum.size(),
      42           0 :               noise_spectrum_);
      43             :   } else {
      44             :     // Smoothly update the noise spectral estimate towards the signal spectrum
      45             :     // such that the magnitude of the updates are limited.
      46           0 :     for (size_t k = 0; k < spectrum.size(); ++k) {
      47           0 :       if (noise_spectrum_[k] < spectrum[k]) {
      48           0 :         noise_spectrum_[k] = std::min(
      49           0 :             1.01f * noise_spectrum_[k],
      50           0 :             noise_spectrum_[k] + 0.05f * (spectrum[k] - noise_spectrum_[k]));
      51             :       } else {
      52           0 :         noise_spectrum_[k] = std::max(
      53           0 :             0.99f * noise_spectrum_[k],
      54           0 :             noise_spectrum_[k] + 0.05f * (spectrum[k] - noise_spectrum_[k]));
      55             :       }
      56             :     }
      57             :   }
      58             : 
      59             :   // Ensure that the noise spectal estimate does not become too low.
      60           0 :   for (auto& v : noise_spectrum_) {
      61           0 :     v = std::max(v, kMinNoisePower);
      62             :   }
      63             : 
      64           0 :   data_dumper_->DumpRaw("lc_noise_spectrum", 65, noise_spectrum_);
      65           0 :   data_dumper_->DumpRaw("lc_signal_spectrum", spectrum);
      66           0 : }
      67             : 
      68             : }  // namespace webrtc