1 /* 2 * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_AGC_HISTOGRAM_H_ 12 #define WEBRTC_MODULES_AUDIO_PROCESSING_AGC_HISTOGRAM_H_ 13 14 #include <string.h> 15 16 #include "webrtc/base/scoped_ptr.h" 17 #include "webrtc/typedefs.h" 18 19 namespace webrtc { 20 21 // This class implements the histogram of loudness with circular buffers so that 22 // the histogram tracks the last T seconds of the loudness. 23 class Histogram { 24 public: 25 // Create a non-sliding Histogram. 26 static Histogram* Create(); 27 28 // Create a sliding Histogram, i.e. the histogram represents the last 29 // |window_size| samples. 30 static Histogram* Create(int window_size); 31 ~Histogram(); 32 33 // Insert RMS and the corresponding activity probability. 34 void Update(double rms, double activity_probability); 35 36 // Reset the histogram, forget the past. 37 void Reset(); 38 39 // Current loudness, which is actually the mean of histogram in loudness 40 // domain. 41 double CurrentRms() const; 42 43 // Sum of the histogram content. 44 double AudioContent() const; 45 46 // Number of times the histogram has been updated. 47 int num_updates() const { return num_updates_; } 48 49 private: 50 Histogram(); 51 explicit Histogram(int window); 52 53 // Find the histogram bin associated with the given |rms|. 54 int GetBinIndex(double rms); 55 56 void RemoveOldestEntryAndUpdate(); 57 void InsertNewestEntryAndUpdate(int activity_prob_q10, int hist_index); 58 void UpdateHist(int activity_prob_q10, int hist_index); 59 void RemoveTransient(); 60 61 // Number of histogram bins. 62 static const int kHistSize = 77; 63 64 // Number of times the histogram is updated 65 int num_updates_; 66 // Audio content, this should be equal to the sum of the components of 67 // |bin_count_q10_|. 68 int64_t audio_content_q10_; 69 70 // Histogram of input RMS in Q10 with |kHistSize_| bins. In each 'Update(),' 71 // we increment the associated histogram-bin with the given probability. The 72 // increment is implemented in Q10 to avoid rounding errors. 73 int64_t bin_count_q10_[kHistSize]; 74 75 // Circular buffer for probabilities 76 rtc::scoped_ptr<int[]> activity_probability_; 77 // Circular buffer for histogram-indices of probabilities. 78 rtc::scoped_ptr<int[]> hist_bin_index_; 79 // Current index of circular buffer, where the newest data will be written to, 80 // therefore, pointing to the oldest data if buffer is full. 81 int buffer_index_; 82 // Indicating if buffer is full and we had a wrap around. 83 int buffer_is_full_; 84 // Size of circular buffer. 85 int len_circular_buffer_; 86 int len_high_activity_; 87 }; 88 89 } // namespace webrtc 90 91 #endif // WEBRTC_MODULES_AUDIO_PROCESSING_AGC_HISTOGRAM_H_ 92
