suppression_gain.h

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/*

 *  Copyright (c) 2017 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.

*/

#ifndef MODULES_AUDIO_PROCESSING_AEC3_SUPPRESSION_GAIN_H_

#define MODULES_AUDIO_PROCESSING_AEC3_SUPPRESSION_GAIN_H_

#include <array>

#include <atomic>

#include <memory>

#include <vector>

#include "absl/types/optional.h"

#include "api/array_view.h"

#include "api/audio/echo_canceller3_config.h"

#include "modules/audio_processing/aec3/aec3_common.h"

#include "modules/audio_processing/aec3/aec_state.h"

#include "modules/audio_processing/aec3/fft_data.h"

#include "modules/audio_processing/aec3/moving_average.h"

#include "modules/audio_processing/aec3/nearend_detector.h"

#include "modules/audio_processing/aec3/render_signal_analyzer.h"

#include "modules/audio_processing/logging/apm_data_dumper.h"

namespace webrtc {

class SuppressionGain {

 public:

  SuppressionGain(const EchoCanceller3Config& config,

                  Aec3Optimization optimization,

                  int sample_rate_hz,

                  size_t num_capture_channels);

  ~SuppressionGain();

  SuppressionGain(const SuppressionGain&) = delete;

  SuppressionGain& operator=(const SuppressionGain&) = delete;

  void GetGain(

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>

          nearend_spectrum,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> echo_spectrum,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>

          residual_echo_spectrum,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>

          residual_echo_spectrum_unbounded,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>

          comfort_noise_spectrum,

      const RenderSignalAnalyzer& render_signal_analyzer,

      const AecState& aec_state,

      const Block& render,

      bool clock_drift,

      float* high_bands_gain,

      std::array<float, kFftLengthBy2Plus1>* low_band_gain);

  bool IsDominantNearend() {

    return dominant_nearend_detector_->IsNearendState();

  // Toggles the usage of the initial state.

  void SetInitialState(bool state);

 private:

  // Computes the gain to apply for the bands beyond the first band.

  float UpperBandsGain(

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> echo_spectrum,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>

          comfort_noise_spectrum,

      const absl::optional<int>& narrow_peak_band,

      bool saturated_echo,

      const Block& render,

      const std::array<float, kFftLengthBy2Plus1>& low_band_gain) const;

  void GainToNoAudibleEcho(const std::array<float, kFftLengthBy2Plus1>& nearend,

                           const std::array<float, kFftLengthBy2Plus1>& echo,

                           const std::array<float, kFftLengthBy2Plus1>& masker,

                           std::array<float, kFftLengthBy2Plus1>* gain) const;

  void LowerBandGain(

      bool stationary_with_low_power,

      const AecState& aec_state,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>

          suppressor_input,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> residual_echo,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> comfort_noise,

      bool clock_drift,

      std::array<float, kFftLengthBy2Plus1>* gain);

  void GetMinGain(rtc::ArrayView<const float> weighted_residual_echo,

                  rtc::ArrayView<const float> last_nearend,

                  rtc::ArrayView<const float> last_echo,

                  bool low_noise_render,

                  bool saturated_echo,

                  rtc::ArrayView<float> min_gain) const;

  void GetMaxGain(rtc::ArrayView<float> max_gain) const;

  class LowNoiseRenderDetector {

   public:

    bool Detect(const Block& render);

   private:

    float average_power_ = 32768.f * 32768.f;

};

  struct GainParameters {

    explicit GainParameters(

        int last_lf_band,

        int first_hf_band,

        const EchoCanceller3Config::Suppressor::Tuning& tuning);

    const float max_inc_factor;

    const float max_dec_factor_lf;

    std::array<float, kFftLengthBy2Plus1> enr_transparent_;

    std::array<float, kFftLengthBy2Plus1> enr_suppress_;

    std::array<float, kFftLengthBy2Plus1> emr_transparent_;

};

  static std::atomic<int> instance_count_;

  std::unique_ptr<ApmDataDumper> data_dumper_;

  const Aec3Optimization optimization_;

  const EchoCanceller3Config config_;

  const size_t num_capture_channels_;

  const int state_change_duration_blocks_;

  std::array<float, kFftLengthBy2Plus1> last_gain_;

  std::vector<std::array<float, kFftLengthBy2Plus1>> last_nearend_;

  std::vector<std::array<float, kFftLengthBy2Plus1>> last_echo_;

  LowNoiseRenderDetector low_render_detector_;

  bool initial_state_ = true;

  int initial_state_change_counter_ = 0;

  std::vector<aec3::MovingAverage> nearend_smoothers_;

  const GainParameters nearend_params_;

  const GainParameters normal_params_;

  // Determines if the dominant nearend detector uses the unbounded residual

  // echo spectrum.

  const bool use_unbounded_echo_spectrum_;

  std::unique_ptr<NearendDetector> dominant_nearend_detector_;

};

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_AEC3_SUPPRESSION_GAIN_H_