Finalization of the first version of EchoCanceller 3

webrtc/modules/audio_processing/aec3/power_echo_model.h

+/*
+ *  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_POWER_ECHO_MODEL_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_POWER_ECHO_MODEL_H_
+
+#include <array>
+
+#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/aec_state.h"
+#include "webrtc/modules/audio_processing/aec3/echo_path_variability.h"
+#include "webrtc/modules/audio_processing/aec3/fft_buffer.h"
+
+namespace webrtc {
+
+// Provides an echo model based on power spectral estimates that estimates the
+// echo spectrum.
+class PowerEchoModel {
+ public:
+  PowerEchoModel();
+  ~PowerEchoModel();
+
+  // Ajusts the model according to echo path changes.
+  void HandleEchoPathChange(const EchoPathVariability& variability);
+
+  // Updates the echo model and estimates the echo spectrum.
+  void EstimateEcho(
+      const FftBuffer& render_buffer,
+      const std::array<float, kFftLengthBy2Plus1>& capture_spectrum,
+      const AecState& aec_state,
+      std::array<float, kFftLengthBy2Plus1>* echo_spectrum);
+
+  // Returns the minimum required farend buffer length.
+  size_t MinFarendBufferLength() const { return kRenderBufferSize; }
+
+ private:
+  // Provides a float value that is coupled with a counter.
+  struct CountedFloat {
+    CountedFloat() : value(0.f), counter(0) {}
+    CountedFloat(float value, int counter) : value(value), counter(counter) {}
+    float value;
+    int counter;
+  };
+
+  const size_t kRenderBufferSize = 100;
+  std::array<CountedFloat, kFftLengthBy2Plus1> H2_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(PowerEchoModel);
+};
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_POWER_ECHO_MODEL_H_