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_ERLE_ESTIMATOR_H_
12 #define MODULES_AUDIO_PROCESSING_AEC3_ERLE_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 enhancement based on the signal spectra.
22 class ErleEstimator {
23  public:
24   ErleEstimator(float min_erle, float max_erle_lf, float max_erle_hf);
25   ~ErleEstimator();
26 
27   // Updates the ERLE estimate.
28   void Update(const std::array<float, kFftLengthBy2Plus1>& render_spectrum,
29               const std::array<float, kFftLengthBy2Plus1>& capture_spectrum,
30               const std::array<float, kFftLengthBy2Plus1>& subtractor_spectrum);
31 
32   // Returns the most recent ERLE estimate.
Erle()33   const std::array<float, kFftLengthBy2Plus1>& Erle() const { return erle_; }
ErleTimeDomain()34   float ErleTimeDomain() const { return erle_time_domain_; }
35 
36  private:
37   std::array<float, kFftLengthBy2Plus1> erle_;
38   std::array<int, kFftLengthBy2Minus1> hold_counters_;
39   float erle_time_domain_;
40   int hold_counter_time_domain_;
41   const float min_erle_;
42   const float max_erle_lf_;
43   const float max_erle_hf_;
44 
45   RTC_DISALLOW_COPY_AND_ASSIGN(ErleEstimator);
46 };
47 
48 }  // namespace webrtc
49 
50 #endif  // MODULES_AUDIO_PROCESSING_AEC3_ERLE_ESTIMATOR_H_
51