1 files changed, 300 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/aec3/aec_state.h b/third_party/libwebrtc/modules/audio_processing/aec3/aec_state.h
new file mode 100644
index 0000000000..a39325c8b8
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/aec3/aec_state.h
@@ -0,0 +1,300 @@
+/*
+ *  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_AEC_STATE_H_
+#define MODULES_AUDIO_PROCESSING_AEC3_AEC_STATE_H_
+
+#include <stddef.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/delay_estimate.h"
+#include "modules/audio_processing/aec3/echo_audibility.h"
+#include "modules/audio_processing/aec3/echo_path_variability.h"
+#include "modules/audio_processing/aec3/erl_estimator.h"
+#include "modules/audio_processing/aec3/erle_estimator.h"
+#include "modules/audio_processing/aec3/filter_analyzer.h"
+#include "modules/audio_processing/aec3/render_buffer.h"
+#include "modules/audio_processing/aec3/reverb_model_estimator.h"
+#include "modules/audio_processing/aec3/subtractor_output.h"
+#include "modules/audio_processing/aec3/subtractor_output_analyzer.h"
+#include "modules/audio_processing/aec3/transparent_mode.h"
+
+namespace webrtc {
+
+class ApmDataDumper;
+
+// Handles the state and the conditions for the echo removal functionality.
+class AecState {
+ public:
+  AecState(const EchoCanceller3Config& config, size_t num_capture_channels);
+  ~AecState();
+
+  // Returns whether the echo subtractor can be used to determine the residual
+  // echo.
+  bool UsableLinearEstimate() const {
+    return filter_quality_state_.LinearFilterUsable() &&
+           config_.filter.use_linear_filter;
+  }
+
+  // Returns whether the echo subtractor output should be used as output.
+  bool UseLinearFilterOutput() const {
+    return filter_quality_state_.LinearFilterUsable() &&
+           config_.filter.use_linear_filter;
+  }
+
+  // Returns whether the render signal is currently active.
+  bool ActiveRender() const { return blocks_with_active_render_ > 200; }
+
+  // Returns the appropriate scaling of the residual echo to match the
+  // audibility.
+  void GetResidualEchoScaling(rtc::ArrayView<float> residual_scaling) const;
+
+  // Returns whether the stationary properties of the signals are used in the
+  // aec.
+  bool UseStationarityProperties() const {
+    return config_.echo_audibility.use_stationarity_properties;
+  }
+
+  // Returns the ERLE.
+  rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> Erle(
+      bool onset_compensated) const {
+    return erle_estimator_.Erle(onset_compensated);
+  }
+
+  // Returns the non-capped ERLE.
+  rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> ErleUnbounded()
+      const {
+    return erle_estimator_.ErleUnbounded();
+  }
+
+  // Returns the fullband ERLE estimate in log2 units.
+  float FullBandErleLog2() const { return erle_estimator_.FullbandErleLog2(); }
+
+  // Returns the ERL.
+  const std::array<float, kFftLengthBy2Plus1>& Erl() const {
+    return erl_estimator_.Erl();
+  }
+
+  // Returns the time-domain ERL.
+  float ErlTimeDomain() const { return erl_estimator_.ErlTimeDomain(); }
+
+  // Returns the delay estimate based on the linear filter.
+  int MinDirectPathFilterDelay() const {
+    return delay_state_.MinDirectPathFilterDelay();
+  }
+
+  // Returns whether the capture signal is saturated.
+  bool SaturatedCapture() const { return capture_signal_saturation_; }
+
+  // Returns whether the echo signal is saturated.
+  bool SaturatedEcho() const { return saturation_detector_.SaturatedEcho(); }
+
+  // Updates the capture signal saturation.
+  void UpdateCaptureSaturation(bool capture_signal_saturation) {
+    capture_signal_saturation_ = capture_signal_saturation;
+  }
+
+  // Returns whether the transparent mode is active
+  bool TransparentModeActive() const {
+    return transparent_state_ && transparent_state_->Active();
+  }
+
+  // Takes appropriate action at an echo path change.
+  void HandleEchoPathChange(const EchoPathVariability& echo_path_variability);
+
+  // Returns the decay factor for the echo reverberation. The parameter `mild`
+  // indicates which exponential decay to return. The default one or a milder
+  // one that can be used during nearend regions.
+  float ReverbDecay(bool mild) const {
+    return reverb_model_estimator_.ReverbDecay(mild);
+  }
+
+  // Return the frequency response of the reverberant echo.
+  rtc::ArrayView<const float> GetReverbFrequencyResponse() const {
+    return reverb_model_estimator_.GetReverbFrequencyResponse();
+  }
+
+  // Returns whether the transition for going out of the initial stated has
+  // been triggered.
+  bool TransitionTriggered() const {
+    return initial_state_.TransitionTriggered();
+  }
+
+  // Updates the aec state.
+  // TODO(bugs.webrtc.org/10913): Compute multi-channel ERL.
+  void Update(
+      const absl::optional<DelayEstimate>& external_delay,
+      rtc::ArrayView<const std::vector<std::array<float, kFftLengthBy2Plus1>>>
+          adaptive_filter_frequency_responses,
+      rtc::ArrayView<const std::vector<float>>
+          adaptive_filter_impulse_responses,
+      const RenderBuffer& render_buffer,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> E2_refined,
+      rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> Y2,
+      rtc::ArrayView<const SubtractorOutput> subtractor_output);
+
+  // Returns filter length in blocks.
+  int FilterLengthBlocks() const {
+    // All filters have the same length, so arbitrarily return channel 0 length.
+    return filter_analyzer_.FilterLengthBlocks();
+  }
+
+ private:
+  static std::atomic<int> instance_count_;
+  std::unique_ptr<ApmDataDumper> data_dumper_;
+  const EchoCanceller3Config config_;
+  const size_t num_capture_channels_;
+  const bool deactivate_initial_state_reset_at_echo_path_change_;
+  const bool full_reset_at_echo_path_change_;
+  const bool subtractor_analyzer_reset_at_echo_path_change_;
+
+  // Class for controlling the transition from the intial state, which in turn
+  // controls when the filter parameters for the initial state should be used.
+  class InitialState {
+   public:
+    explicit InitialState(const EchoCanceller3Config& config);
+    // Resets the state to again begin in the initial state.
+    void Reset();
+
+    // Updates the state based on new data.
+    void Update(bool active_render, bool saturated_capture);
+
+    // Returns whether the initial state is active or not.
+    bool InitialStateActive() const { return initial_state_; }
+
+    // Returns that the transition from the initial state has was started.
+    bool TransitionTriggered() const { return transition_triggered_; }
+
+   private:
+    const bool conservative_initial_phase_;
+    const float initial_state_seconds_;
+    bool transition_triggered_ = false;
+    bool initial_state_ = true;
+    size_t strong_not_saturated_render_blocks_ = 0;
+  } initial_state_;
+
+  // Class for choosing the direct-path delay relative to the beginning of the
+  // filter, as well as any other data related to the delay used within
+  // AecState.
+  class FilterDelay {
+   public:
+    FilterDelay(const EchoCanceller3Config& config,
+                size_t num_capture_channels);
+
+    // Returns whether an external delay has been reported to the AecState (from
+    // the delay estimator).
+    bool ExternalDelayReported() const { return external_delay_reported_; }
+
+    // Returns the delay in blocks relative to the beginning of the filter that
+    // corresponds to the direct path of the echo.
+    rtc::ArrayView<const int> DirectPathFilterDelays() const {
+      return filter_delays_blocks_;
+    }
+
+    // Returns the minimum delay among the direct path delays relative to the
+    // beginning of the filter
+    int MinDirectPathFilterDelay() const { return min_filter_delay_; }
+
+    // Updates the delay estimates based on new data.
+    void Update(
+        rtc::ArrayView<const int> analyzer_filter_delay_estimates_blocks,
+        const absl::optional<DelayEstimate>& external_delay,
+        size_t blocks_with_proper_filter_adaptation);
+
+   private:
+    const int delay_headroom_blocks_;
+    bool external_delay_reported_ = false;
+    std::vector<int> filter_delays_blocks_;
+    int min_filter_delay_;
+    absl::optional<DelayEstimate> external_delay_;
+  } delay_state_;
+
+  // Classifier for toggling transparent mode when there is no echo.
+  std::unique_ptr<TransparentMode> transparent_state_;
+
+  // Class for analyzing how well the linear filter is, and can be expected to,
+  // perform on the current signals. The purpose of this is for using to
+  // select the echo suppression functionality as well as the input to the echo
+  // suppressor.
+  class FilteringQualityAnalyzer {
+   public:
+    FilteringQualityAnalyzer(const EchoCanceller3Config& config,
+                             size_t num_capture_channels);
+
+    // Returns whether the linear filter can be used for the echo
+    // canceller output.
+    bool LinearFilterUsable() const { return overall_usable_linear_estimates_; }
+
+    // Returns whether an individual filter output can be used for the echo
+    // canceller output.
+    const std::vector<bool>& UsableLinearFilterOutputs() const {
+      return usable_linear_filter_estimates_;
+    }
+
+    // Resets the state of the analyzer.
+    void Reset();
+
+    // Updates the analysis based on new data.
+    void Update(bool active_render,
+                bool transparent_mode,
+                bool saturated_capture,
+                const absl::optional<DelayEstimate>& external_delay,
+                bool any_filter_converged);
+
+   private:
+    const bool use_linear_filter_;
+    bool overall_usable_linear_estimates_ = false;
+    size_t filter_update_blocks_since_reset_ = 0;
+    size_t filter_update_blocks_since_start_ = 0;
+    bool convergence_seen_ = false;
+    std::vector<bool> usable_linear_filter_estimates_;
+  } filter_quality_state_;
+
+  // Class for detecting whether the echo is to be considered to be
+  // saturated.
+  class SaturationDetector {
+   public:
+    // Returns whether the echo is to be considered saturated.
+    bool SaturatedEcho() const { return saturated_echo_; }
+
+    // Updates the detection decision based on new data.
+    void Update(const Block& x,
+                bool saturated_capture,
+                bool usable_linear_estimate,
+                rtc::ArrayView<const SubtractorOutput> subtractor_output,
+                float echo_path_gain);
+
+   private:
+    bool saturated_echo_ = false;
+  } saturation_detector_;
+
+  ErlEstimator erl_estimator_;
+  ErleEstimator erle_estimator_;
+  size_t strong_not_saturated_render_blocks_ = 0;
+  size_t blocks_with_active_render_ = 0;
+  bool capture_signal_saturation_ = false;
+  FilterAnalyzer filter_analyzer_;
+  EchoAudibility echo_audibility_;
+  ReverbModelEstimator reverb_model_estimator_;
+  ReverbModel avg_render_reverb_;
+  SubtractorOutputAnalyzer subtractor_output_analyzer_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AEC3_AEC_STATE_H_