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The Tor Browser
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echo_audibility.h (3093B)

      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 <optional>
     17 
     18 #include "api/array_view.h"
     19 #include "modules/audio_processing/aec3/block_buffer.h"
     20 #include "modules/audio_processing/aec3/render_buffer.h"
     21 #include "modules/audio_processing/aec3/spectrum_buffer.h"
     22 #include "modules/audio_processing/aec3/stationarity_estimator.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              ArrayView<const float> average_reverb,
     37              int min_channel_delay_blocks,
     38              bool external_delay_seen);
     39  // Get the residual echo scaling.
     40  void GetResidualEchoScaling(bool filter_has_had_time_to_converge,
     41                              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.
     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                                     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  std::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_