text: /*
   *  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/aec3/subtractor_output_analyzer.h"
  
  #include <algorithm>
  
  #include "modules/audio_processing/aec3/aec3_common.h"
  #include "system_wrappers/include/field_trial.h"
  
  namespace webrtc {
  namespace {
  
  bool EnableStrictDivergenceCheck() {
    return !field_trial::IsEnabled("WebRTC-Aec3StrictDivergenceCheckKillSwitch");
  }
  
  }  // namespace
  
  SubtractorOutputAnalyzer::SubtractorOutputAnalyzer()
      : strict_divergence_check_(EnableStrictDivergenceCheck()) {}
  
  void SubtractorOutputAnalyzer::Update(
      const SubtractorOutput& subtractor_output) {
    const float y2 = subtractor_output.y2;
    const float e2_main = subtractor_output.e2_main;
    const float e2_shadow = subtractor_output.e2_shadow;
  
    constexpr float kConvergenceThreshold = 50 * 50 * kBlockSize;
    main_filter_converged_ = e2_main < 0.5f * y2 && y2 > kConvergenceThreshold;
    shadow_filter_converged_ =
        e2_shadow < 0.05f * y2 && y2 > kConvergenceThreshold;
    float min_e2 =
        strict_divergence_check_ ? std::min(e2_main, e2_shadow) : e2_main;
    filter_diverged_ = min_e2 > 1.5f * y2 && y2 > 30.f * 30.f * kBlockSize;
  }
  
  void SubtractorOutputAnalyzer::HandleEchoPathChange() {
    shadow_filter_converged_ = false;
    main_filter_converged_ = false;
    filter_diverged_ = false;
  }
  
  }  // namespace webrtc
  