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/*
* Copyright (c) 2012 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_VAD_VAD_CIRCULAR_BUFFER_H_
#define MODULES_AUDIO_PROCESSING_VAD_VAD_CIRCULAR_BUFFER_H_
#include <memory>
namespace webrtc {
// A circular buffer tailored to the need of this project. It stores last
// K samples of the input, and keeps track of the mean of the last samples.
//
// It is used in class "PitchBasedActivity" to keep track of posterior
// probabilities in the past few seconds. The posterior probabilities are used
// to recursively update prior probabilities.
class VadCircularBuffer {
public:
static VadCircularBuffer* Create(int buffer_size);
~VadCircularBuffer();
// If buffer is wrapped around.
bool is_full() const { return is_full_; }
// Get the oldest entry in the buffer.
double Oldest() const;
// Insert new value into the buffer.
void Insert(double value);
// Reset buffer, forget the past, start fresh.
void Reset();
// The mean value of the elements in the buffer. The return value is zero if
// buffer is empty, i.e. no value is inserted.
double Mean();
// Remove transients. If the values exceed `val_threshold` for a period
// shorter then or equal to `width_threshold`, then that period is considered
// transient and set to zero.
int RemoveTransient(int width_threshold, double val_threshold);
private:
explicit VadCircularBuffer(int buffer_size);
// Get previous values. |index = 0| corresponds to the most recent
// insertion. |index = 1| is the one before the most recent insertion, and
// so on.
int Get(int index, double* value) const;
// Set a given position to `value`. `index` is interpreted as above.
int Set(int index, double value);
// Return the number of valid elements in the buffer.
int BufferLevel();
// Convert an index with the interpretation as get() method to the
// corresponding linear index.
int ConvertToLinearIndex(int* index) const;
std::unique_ptr<double[]> buffer_;
bool is_full_;
int index_;
int buffer_size_;
double sum_;
};
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_VAD_VAD_CIRCULAR_BUFFER_H_
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