residual_echo_estimator.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_RESIDUAL_ECHO_ESTIMATOR_H_

#define MODULES_AUDIO_PROCESSING_AEC3_RESIDUAL_ECHO_ESTIMATOR_H_

#include <array>

#include <memory>

#include "absl/types/optional.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/render_buffer.h"

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

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

#include "rtc_base/checks.h"

namespace webrtc {

class ResidualEchoEstimator {

 public:

  ResidualEchoEstimator(const EchoCanceller3Config& config,

                        size_t num_render_channels);

  ~ResidualEchoEstimator();

  ResidualEchoEstimator(const ResidualEchoEstimator&) = delete;

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

  void Estimate(

      const AecState& aec_state,

      const RenderBuffer& render_buffer,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> S2_linear,

      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> Y2,

      bool dominant_nearend,

      rtc::ArrayView<std::array<float, kFftLengthBy2Plus1>> R2,

      rtc::ArrayView<std::array<float, kFftLengthBy2Plus1>> R2_unbounded);

 private:

  enum class ReverbType { kLinear, kNonLinear };

  // Resets the state.

  void Reset();

  // Updates estimate for the power of the stationary noise component in the

  // render signal.

  void UpdateRenderNoisePower(const RenderBuffer& render_buffer);

  // Updates the reverb estimation.

  void UpdateReverb(ReverbType reverb_type,

                    const AecState& aec_state,

                    const RenderBuffer& render_buffer,

                    bool dominant_nearend);

  // Adds the estimated unmodelled echo power to the residual echo power

  // estimate.

  void AddReverb(

      rtc::ArrayView<std::array<float, kFftLengthBy2Plus1>> R2) const;

  // Gets the echo path gain to apply.

  float GetEchoPathGain(const AecState& aec_state,

                        bool gain_for_early_reflections) const;

  const EchoCanceller3Config config_;

  const size_t num_render_channels_;

  const float early_reflections_transparent_mode_gain_;

  const float late_reflections_transparent_mode_gain_;

  const float early_reflections_general_gain_;

  const float late_reflections_general_gain_;

  const bool erle_onset_compensation_in_dominant_nearend_;

  std::array<float, kFftLengthBy2Plus1> X2_noise_floor_;

  std::array<int, kFftLengthBy2Plus1> X2_noise_floor_counter_;

  ReverbModel echo_reverb_;

};

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_AEC3_RESIDUAL_ECHO_ESTIMATOR_H_