Finalization of the first version of EchoCanceller 3

webrtc/modules/audio_processing/aec3/erl_estimator.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_ERL_ESTIMATOR_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_ERL_ESTIMATOR_H_
+
+#include <array>
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_common.h"
+
+namespace webrtc {
+
+// Estimates the echo return loss based on the signal spectra.
+class ErlEstimator {
+ public:
+  ErlEstimator();
+  ~ErlEstimator();
+
+  // Updates the ERL estimate.
+  void Update(const std::array<float, kFftLengthBy2Plus1>& render_spectrum,
+              const std::array<float, kFftLengthBy2Plus1>& capture_spectrum);
+
+  // Returns the most recent ERL estimate.
+  const std::array<float, kFftLengthBy2Plus1>& Erl() const { return erl_; }
+
+ private:
+  std::array<float, kFftLengthBy2Plus1> erl_;
+  std::array<int, kFftLengthBy2Minus1> hold_counters_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(ErlEstimator);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_ERL_ESTIMATOR_H_