| /* |
| * 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 WEBRTC_MODULES_AUDIO_PROCESSING_VAD_VAD_CIRCULAR_BUFFER_H_ |
| #define WEBRTC_MODULES_AUDIO_PROCESSING_VAD_VAD_CIRCULAR_BUFFER_H_ |
| |
| #include "webrtc/base/scoped_ptr.h" |
| |
| 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; |
| |
| rtc::scoped_ptr<double[]> buffer_; |
| bool is_full_; |
| int index_; |
| int buffer_size_; |
| double sum_; |
| }; |
| |
| } // namespace webrtc |
| #endif // WEBRTC_MODULES_AUDIO_PROCESSING_VAD_VAD_CIRCULAR_BUFFER_H_ |