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* 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.
#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 {
// 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;
void RemoveTransient();
// Use only for testing.
float GetSumProbabilities() const { return sum_probabilities_; }
FRIEND_TEST_ALL_PREFIXES(SpeechProbabilityBufferTest, CheckSumAfterUpdate);
FRIEND_TEST_ALL_PREFIXES(SpeechProbabilityBufferTest, CheckSumAfterReset);
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