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 <stddef.h>
15 
16 #include <array>
17 #include <vector>
18 
19 #include "api/array_view.h"
20 #include "modules/audio_processing/aec3/aec3_common.h"
21 #include "rtc_base/constructor_magic.h"
22 
23 namespace webrtc {
24 
25 // Estimates the echo return loss based on the signal spectra.
26 class ErlEstimator {
27  public:
28   explicit ErlEstimator(size_t startup_phase_length_blocks_);
29   ~ErlEstimator();
30 
31   // Resets the ERL estimation.
32   void Reset();
33 
34   // Updates the ERL estimate.
35   void Update(const std::vector<bool>& converged_filters,
36               rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
37                   render_spectra,
38               rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
39                   capture_spectra);
40 
41   // Returns the most recent ERL estimate.
Erl()42   const std::array<float, kFftLengthBy2Plus1>& Erl() const { return erl_; }
ErlTimeDomain()43   float ErlTimeDomain() const { return erl_time_domain_; }
44 
45  private:
46   const size_t startup_phase_length_blocks__;
47   std::array<float, kFftLengthBy2Plus1> erl_;
48   std::array<int, kFftLengthBy2Minus1> hold_counters_;
49   float erl_time_domain_;
50   int hold_counter_time_domain_;
51   size_t blocks_since_reset_ = 0;
52   RTC_DISALLOW_COPY_AND_ASSIGN(ErlEstimator);
53 };
54 
55 }  // namespace webrtc
56 
57 #endif  // MODULES_AUDIO_PROCESSING_AEC3_ERL_ESTIMATOR_H_
58