1 /*
2  *  Copyright (c) 2018 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_REVERB_MODEL_H_
12 #define MODULES_AUDIO_PROCESSING_AEC3_REVERB_MODEL_H_
13 
14 #include <array>
15 
16 #include "api/array_view.h"
17 #include "modules/audio_processing/aec3/aec3_common.h"
18 
19 namespace webrtc {
20 
21 // The ReverbModel class describes an exponential reverberant model
22 // that can be applied over power spectrums.
23 class ReverbModel {
24  public:
25   ReverbModel();
26   ~ReverbModel();
27 
28   // Resets the state.
29   void Reset();
30 
31   // Returns the reverb.
reverb()32   rtc::ArrayView<const float, kFftLengthBy2Plus1> reverb() const {
33     return reverb_;
34   }
35 
36   // The methods UpdateReverbNoFreqShaping and UpdateReverb update the
37   // estimate of the reverberation contribution to an input/output power
38   // spectrum. Before applying the exponential reverberant model, the input
39   // power spectrum is pre-scaled. Use the method UpdateReverb when a different
40   // scaling should be applied per frequency and UpdateReverb_no_freq_shape if
41   // the same scaling should be used for all the frequencies.
42   void UpdateReverbNoFreqShaping(rtc::ArrayView<const float> power_spectrum,
43                                  float power_spectrum_scaling,
44                                  float reverb_decay);
45 
46   // Update the reverb based on new data.
47   void UpdateReverb(rtc::ArrayView<const float> power_spectrum,
48                     rtc::ArrayView<const float> power_spectrum_scaling,
49                     float reverb_decay);
50 
51  private:
52 
53   std::array<float, kFftLengthBy2Plus1> reverb_;
54 };
55 
56 }  // namespace webrtc
57 
58 #endif  // MODULES_AUDIO_PROCESSING_AEC3_REVERB_MODEL_H_
59