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_ECHO_AUDIBILITY_H_
12 #define MODULES_AUDIO_PROCESSING_AEC3_ECHO_AUDIBILITY_H_
13 
14 #include <stddef.h>
15 
16 #include "absl/types/optional.h"
17 #include "api/array_view.h"
18 #include "modules/audio_processing/aec3/block_buffer.h"
19 #include "modules/audio_processing/aec3/render_buffer.h"
20 #include "modules/audio_processing/aec3/spectrum_buffer.h"
21 #include "modules/audio_processing/aec3/stationarity_estimator.h"
22 #include "rtc_base/constructor_magic.h"
23 
24 namespace webrtc {
25 
26 class EchoAudibility {
27  public:
28   explicit EchoAudibility(bool use_render_stationarity_at_init);
29   ~EchoAudibility();
30 
31   EchoAudibility(const EchoAudibility&) = delete;
32   EchoAudibility& operator=(const EchoAudibility&) = delete;
33 
34   // Feed new render data to the echo audibility estimator.
35   void Update(const RenderBuffer& render_buffer,
36               rtc::ArrayView<const float> average_reverb,
37               int min_channel_delay_blocks,
38               bool external_delay_seen);
39   // Get the residual echo scaling.
GetResidualEchoScaling(bool filter_has_had_time_to_converge,rtc::ArrayView<float> residual_scaling)40   void GetResidualEchoScaling(bool filter_has_had_time_to_converge,
41                               rtc::ArrayView<float> residual_scaling) const {
42     for (size_t band = 0; band < residual_scaling.size(); ++band) {
43       if (render_stationarity_.IsBandStationary(band) &&
44           (filter_has_had_time_to_converge ||
45            use_render_stationarity_at_init_)) {
46         residual_scaling[band] = 0.f;
47       } else {
48         residual_scaling[band] = 1.0f;
49       }
50     }
51   }
52 
53   // Returns true if the current render block is estimated as stationary.
IsBlockStationary()54   bool IsBlockStationary() const {
55     return render_stationarity_.IsBlockStationary();
56   }
57 
58  private:
59   // Reset the EchoAudibility class.
60   void Reset();
61 
62   // Updates the render stationarity flags for the current frame.
63   void UpdateRenderStationarityFlags(const RenderBuffer& render_buffer,
64                                      rtc::ArrayView<const float> average_reverb,
65                                      int delay_blocks);
66 
67   // Updates the noise estimator with the new render data since the previous
68   // call to this method.
69   void UpdateRenderNoiseEstimator(const SpectrumBuffer& spectrum_buffer,
70                                   const BlockBuffer& block_buffer,
71                                   bool external_delay_seen);
72 
73   // Returns a bool being true if the render signal contains just close to zero
74   // values.
75   bool IsRenderTooLow(const BlockBuffer& block_buffer);
76 
77   absl::optional<int> render_spectrum_write_prev_;
78   int render_block_write_prev_;
79   bool non_zero_render_seen_;
80   const bool use_render_stationarity_at_init_;
81   StationarityEstimator render_stationarity_;
82 };
83 
84 }  // namespace webrtc
85 
86 #endif  // MODULES_AUDIO_PROCESSING_AEC3_ECHO_AUDIBILITY_H_
87