speech_probability_buffer.h

Enable keyboard shortcuts

/*

 *  Copyright (c) 2022 The WebRTC project authors. All Rights Reserved.

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

*/

#ifndef MODULES_AUDIO_PROCESSING_AGC2_SPEECH_PROBABILITY_BUFFER_H_

#define MODULES_AUDIO_PROCESSING_AGC2_SPEECH_PROBABILITY_BUFFER_H_

#include <vector>

#include "rtc_base/gtest_prod_util.h"

namespace webrtc {

// This class implements a circular buffer that stores speech probabilities

// for a speech segment and estimates speech activity for that segment.

class SpeechProbabilityBuffer {

 public:

  // Ctor. The value of `low_probability_threshold` is required to be on the

  // range [0.0f, 1.0f].

  explicit SpeechProbabilityBuffer(float low_probability_threshold);

  ~SpeechProbabilityBuffer() {}

  SpeechProbabilityBuffer(const SpeechProbabilityBuffer&) = delete;

  SpeechProbabilityBuffer& operator=(const SpeechProbabilityBuffer&) = delete;

  // Adds `probability` in the buffer and computes an updatds sum of the buffer

  // probabilities. Value of `probability` is required to be on the range

  // [0.0f, 1.0f].

  void Update(float probability);

  // Resets the histogram, forgets the past.

  void Reset();

  // Returns true if the segment is active (a long enough segment with an

  // average speech probability above `low_probability_threshold`).

  bool IsActiveSegment() const;

 private:

  void RemoveTransient();

  // Use only for testing.

  float GetSumProbabilities() const { return sum_probabilities_; }

  FRIEND_TEST_ALL_PREFIXES(SpeechProbabilityBufferTest,

                           CheckSumAfterInitialization);

  FRIEND_TEST_ALL_PREFIXES(SpeechProbabilityBufferTest, CheckSumAfterUpdate);

  FRIEND_TEST_ALL_PREFIXES(SpeechProbabilityBufferTest, CheckSumAfterReset);

  FRIEND_TEST_ALL_PREFIXES(SpeechProbabilityBufferTest,

                           CheckSumAfterTransientNotRemoved);

  FRIEND_TEST_ALL_PREFIXES(SpeechProbabilityBufferTest,

                           CheckSumAfterTransientRemoved);

  const float low_probability_threshold_;

  // Sum of probabilities stored in `probabilities_`. Must be updated if

  // `probabilities_` is updated.

  float sum_probabilities_ = 0.0f;

  // Circular buffer for probabilities.

  std::vector<float> probabilities_;

  // Current index of the circular buffer, where the newest data will be written

  // to, therefore, pointing to the oldest data if buffer is full.

  int buffer_index_ = 0;

  // Indicates if the buffer is full and adding a new value removes the oldest

  // value.

  int buffer_is_full_ = false;

  int num_high_probability_observations_ = 0;

};

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_AGC2_SPEECH_PROBABILITY_BUFFER_H_