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