1 /*
2  *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef MODULES_AUDIO_PROCESSING_AEC3_ERL_ESTIMATOR_H_
12 #define MODULES_AUDIO_PROCESSING_AEC3_ERL_ESTIMATOR_H_
13 
14 #include <array>
15 
16 #include "modules/audio_processing/aec3/aec3_common.h"
17 #include "rtc_base/constructormagic.h"
18 
19 namespace webrtc {
20 
21 // Estimates the echo return loss based on the signal spectra.
22 class ErlEstimator {
23  public:
24   ErlEstimator();
25   ~ErlEstimator();
26 
27   // Updates the ERL estimate.
28   void Update(const std::array<float, kFftLengthBy2Plus1>& render_spectrum,
29               const std::array<float, kFftLengthBy2Plus1>& capture_spectrum);
30 
31   // Returns the most recent ERL estimate.
Erl()32   const std::array<float, kFftLengthBy2Plus1>& Erl() const { return erl_; }
ErlTimeDomain()33   float ErlTimeDomain() const { return erl_time_domain_; }
34 
35  private:
36   std::array<float, kFftLengthBy2Plus1> erl_;
37   std::array<int, kFftLengthBy2Minus1> hold_counters_;
38   float erl_time_domain_;
39   int hold_counter_time_domain_;
40 
41   RTC_DISALLOW_COPY_AND_ASSIGN(ErlEstimator);
42 };
43 
44 }  // namespace webrtc
45 
46 #endif  // MODULES_AUDIO_PROCESSING_AEC3_ERL_ESTIMATOR_H_
47