Finalization of the first version of EchoCanceller 3

webrtc/modules/audio_processing/aec3/aec_state.h

Index: webrtc/modules/audio_processing/aec3/aec_state.h
diff --git a/webrtc/modules/audio_processing/aec3/aec_state.h b/webrtc/modules/audio_processing/aec3/aec_state.h
new file mode 100644
index 0000000000000000000000000000000000000000..75868e4da49f59eb3a543f941b8f955945f0dbf3
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+++ b/webrtc/modules/audio_processing/aec3/aec_state.h
@@ -0,0 +1,127 @@
+/*
+ *  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 WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC_STATE_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC_STATE_H_
+
+#include <algorithm>
+#include <memory>
+#include <vector>
+
+#include "webrtc/base/array_view.h"
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/optional.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_common.h"
+#include "webrtc/modules/audio_processing/aec3/echo_path_variability.h"
+#include "webrtc/modules/audio_processing/aec3/erle_estimator.h"
+#include "webrtc/modules/audio_processing/aec3/erl_estimator.h"
+#include "webrtc/modules/audio_processing/aec3/fft_buffer.h"
+
+namespace webrtc {
+
+class ApmDataDumper;
+
+// Handles the state and the conditions for the echo removal functionality.
+class AecState {
+ public:
+  AecState();
+  ~AecState();
+
+  // Returns whether the linear filter estimate is usable.
+  bool UsableLinearEstimate() const { return usable_linear_estimate_; }
+
+  // Returns whether there has been echo leakage detected.
+  bool EchoLeakageDetected() const { return echo_leakage_detected_; }
+
+  // Returns whether it is possible at all to use the model based echo removal
+  // functionalities.
+  bool ModelBasedAecFeasible() const { return model_based_aec_feasible_; }
+
+  // Returns whether the render signal is currently active.
+  bool ActiveRender() const { return active_render_counter_ > 0; }
+
+  // Returns the ERLE.
+  const std::array<float, kFftLengthBy2Plus1>& Erle() const {
+    return erle_estimator_.Erle();
+  }
+
+  // Returns the ERL.
+  const std::array<float, kFftLengthBy2Plus1>& Erl() const {
+    return erl_estimator_.Erl();
+  }
+
+  // Returns the delay estimate based on the linear filter,

[hlundin-webrtc, 2017/02/22 15:24:06]

, -> .

[peah-webrtc, 2017/02/22 23:51:37]

Done.

+  const rtc::Optional<size_t>& FilterDelay() const { return filter_delay_; }

[hlundin-webrtc, 2017/02/22 15:24:06]

I think you should return rtc::Optional<size_t>, not a const reference.

[peah-webrtc, 2017/02/22 23:51:37]

I adopt your suggested change, but I'm not convinced that is the right thing to
do.
If it is a const ref, it is cheap to use code-constructs as

size_t delay = aec_state.FilterDelay() ? *aec_state.FilterDelay() : 0.

Without a reference, that would mean that there are two copies of FilterDelay
being done in that statement.
Please have a look and let me know if you change your mind, in which case I'll
change this back.

Done.

[hlundin-webrtc, 2017/02/23 07:42:09]

Hmm. Yeah, you are probably right. Feel free to change back.

[peah-webrtc, 2017/02/23 11:18:32]

Acknowledged.

+
+  // Returns the externally provided delay.
+  const rtc::Optional<size_t>& ExternalDelay() const { return external_delay_; }

[hlundin-webrtc, 2017/02/22 15:24:06]

I think you should return rtc::Optional<size_t>, not a const reference.

[peah-webrtc, 2017/02/22 23:51:37]

Done.

+
+  // Returns the bands where the linear filter is reliable.
+  const std::array<bool, kFftLengthBy2Plus1>& BandsWithReliableFilter() const {
+    return bands_with_reliable_filter_;
+  }
+
+  // Reports whether the filter is poorly aligned.
+  bool PoorlyAlignedFilter() const {
+    return FilterDelay() ? *FilterDelay() > 0.75f * filter_length_ : false;
+  }
+
+  // Returns the strength of the filter.
+  const std::array<float, kFftLengthBy2Plus1>& FilterEstimateStrength() const {
+    return filter_estimate_strength_;
+  }
+
+  // Returns whether the capture signal is saturated.
+  bool SaturatedCapture() const { return capture_signal_saturation_; }
+
+  // Updates the capture signal saturation.
+  void UpdateCaptureSaturation(bool capture_signal_saturation) {
+    capture_signal_saturation_ = capture_signal_saturation;
+  }
+
+  // Returns whether a probably headset setup has been detected.

[hlundin-webrtc, 2017/02/22 15:24:06]

probably -> probable?

[peah-webrtc, 2017/02/22 23:51:37]

Done.

+  bool HeadsetDetected() const { return headset_detected_; }
+
+  // Updates the aec state.
+  void Update(const std::vector<std::array<float, kFftLengthBy2Plus1>>&
+                  filter_frequency_response,
+              const rtc::Optional<size_t>& external_delay_samples,
+              const FftBuffer& X_buffer,
+              const std::array<float, kFftLengthBy2Plus1>& E2_main,
+              const std::array<float, kFftLengthBy2Plus1>& E2_shadow,
+              const std::array<float, kFftLengthBy2Plus1>& Y2,
+              rtc::ArrayView<const float> x,
+              const EchoPathVariability& echo_path_variability,
+              bool echo_leakage_detected);
+
+ private:
+  static int instance_count_;
+  std::unique_ptr<ApmDataDumper> data_dumper_;
+  ErlEstimator erl_estimator_;
+  ErleEstimator erle_estimator_;
+  int echo_path_change_counter_;
+  int active_render_counter_;
+  bool usable_linear_estimate_ = false;
+  bool echo_leakage_detected_ = false;
+  bool model_based_aec_feasible_ = false;
+  bool capture_signal_saturation_ = false;
+  bool headset_detected_ = false;
+  rtc::Optional<size_t> filter_delay_;
+  rtc::Optional<size_t> external_delay_;
+  std::array<bool, kFftLengthBy2Plus1> bands_with_reliable_filter_;
+  std::array<float, kFftLengthBy2Plus1> filter_estimate_strength_;
+  size_t filter_length_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(AecState);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC_STATE_H_