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_CODING_NETEQ_EXPAND_H_ 12 #define WEBRTC_MODULES_AUDIO_CODING_NETEQ_EXPAND_H_ 13 14 #include <assert.h> 15 16 #include "webrtc/base/constructormagic.h" 17 #include "webrtc/modules/audio_coding/neteq/audio_multi_vector.h" 18 #include "webrtc/system_wrappers/interface/scoped_ptr.h" 19 #include "webrtc/typedefs.h" 20 21 namespace webrtc { 22 23 // Forward declarations. 24 class BackgroundNoise; 25 class RandomVector; 26 class SyncBuffer; 27 28 // This class handles extrapolation of audio data from the sync_buffer to 29 // produce packet-loss concealment. 30 // TODO(hlundin): Refactor this class to divide the long methods into shorter 31 // ones. 32 class Expand { 33 public: Expand(BackgroundNoise * background_noise,SyncBuffer * sync_buffer,RandomVector * random_vector,int fs,size_t num_channels)34 Expand(BackgroundNoise* background_noise, 35 SyncBuffer* sync_buffer, 36 RandomVector* random_vector, 37 int fs, 38 size_t num_channels) 39 : random_vector_(random_vector), 40 sync_buffer_(sync_buffer), 41 first_expand_(true), 42 fs_hz_(fs), 43 num_channels_(num_channels), 44 consecutive_expands_(0), 45 background_noise_(background_noise), 46 overlap_length_(5 * fs / 8000), 47 lag_index_direction_(0), 48 current_lag_index_(0), 49 stop_muting_(false), 50 channel_parameters_(new ChannelParameters[num_channels_]) { 51 assert(fs == 8000 || fs == 16000 || fs == 32000 || fs == 48000); 52 assert(fs <= kMaxSampleRate); // Should not be possible. 53 assert(num_channels_ > 0); 54 memset(expand_lags_, 0, sizeof(expand_lags_)); 55 Reset(); 56 } 57 ~Expand()58 virtual ~Expand() {} 59 60 // Resets the object. 61 virtual void Reset(); 62 63 // The main method to produce concealment data. The data is appended to the 64 // end of |output|. 65 virtual int Process(AudioMultiVector* output); 66 67 // Prepare the object to do extra expansion during normal operation following 68 // a period of expands. 69 virtual void SetParametersForNormalAfterExpand(); 70 71 // Prepare the object to do extra expansion during merge operation following 72 // a period of expands. 73 virtual void SetParametersForMergeAfterExpand(); 74 75 // Sets the mute factor for |channel| to |value|. SetMuteFactor(int16_t value,size_t channel)76 void SetMuteFactor(int16_t value, size_t channel) { 77 assert(channel < num_channels_); 78 channel_parameters_[channel].mute_factor = value; 79 } 80 81 // Returns the mute factor for |channel|. MuteFactor(size_t channel)82 int16_t MuteFactor(size_t channel) { 83 assert(channel < num_channels_); 84 return channel_parameters_[channel].mute_factor; 85 } 86 87 // Accessors and mutators. overlap_length()88 virtual size_t overlap_length() const { return overlap_length_; } max_lag()89 int16_t max_lag() const { return max_lag_; } 90 91 protected: 92 static const int kMaxConsecutiveExpands = 200; 93 void GenerateRandomVector(int seed_increment, 94 size_t length, 95 int16_t* random_vector); 96 97 void GenerateBackgroundNoise(int16_t* random_vector, 98 size_t channel, 99 int16_t mute_slope, 100 bool too_many_expands, 101 size_t num_noise_samples, 102 int16_t* buffer); 103 104 // Initializes member variables at the beginning of an expand period. 105 void InitializeForAnExpandPeriod(); 106 107 bool TooManyExpands(); 108 109 // Analyzes the signal history in |sync_buffer_|, and set up all parameters 110 // necessary to produce concealment data. 111 void AnalyzeSignal(int16_t* random_vector); 112 113 RandomVector* random_vector_; 114 SyncBuffer* sync_buffer_; 115 bool first_expand_; 116 const int fs_hz_; 117 const size_t num_channels_; 118 int consecutive_expands_; 119 120 private: 121 static const int kUnvoicedLpcOrder = 6; 122 static const int kNumCorrelationCandidates = 3; 123 static const int kDistortionLength = 20; 124 static const int kLpcAnalysisLength = 160; 125 static const int kMaxSampleRate = 48000; 126 static const int kNumLags = 3; 127 128 struct ChannelParameters { 129 // Constructor. ChannelParametersChannelParameters130 ChannelParameters() 131 : mute_factor(16384), 132 ar_gain(0), 133 ar_gain_scale(0), 134 voice_mix_factor(0), 135 current_voice_mix_factor(0), 136 onset(false), 137 mute_slope(0) { 138 memset(ar_filter, 0, sizeof(ar_filter)); 139 memset(ar_filter_state, 0, sizeof(ar_filter_state)); 140 } 141 int16_t mute_factor; 142 int16_t ar_filter[kUnvoicedLpcOrder + 1]; 143 int16_t ar_filter_state[kUnvoicedLpcOrder]; 144 int16_t ar_gain; 145 int16_t ar_gain_scale; 146 int16_t voice_mix_factor; /* Q14 */ 147 int16_t current_voice_mix_factor; /* Q14 */ 148 AudioVector expand_vector0; 149 AudioVector expand_vector1; 150 bool onset; 151 int16_t mute_slope; /* Q20 */ 152 }; 153 154 // Calculate the auto-correlation of |input|, with length |input_length| 155 // samples. The correlation is calculated from a downsampled version of 156 // |input|, and is written to |output|. The scale factor is written to 157 // |output_scale|. Returns the length of the correlation vector. 158 int16_t Correlation(const int16_t* input, size_t input_length, 159 int16_t* output, int16_t* output_scale) const; 160 161 void UpdateLagIndex(); 162 163 BackgroundNoise* background_noise_; 164 const size_t overlap_length_; 165 int16_t max_lag_; 166 size_t expand_lags_[kNumLags]; 167 int lag_index_direction_; 168 int current_lag_index_; 169 bool stop_muting_; 170 scoped_ptr<ChannelParameters[]> channel_parameters_; 171 172 DISALLOW_COPY_AND_ASSIGN(Expand); 173 }; 174 175 struct ExpandFactory { ExpandFactoryExpandFactory176 ExpandFactory() {} ~ExpandFactoryExpandFactory177 virtual ~ExpandFactory() {} 178 179 virtual Expand* Create(BackgroundNoise* background_noise, 180 SyncBuffer* sync_buffer, 181 RandomVector* random_vector, 182 int fs, 183 size_t num_channels) const; 184 }; 185 186 } // namespace webrtc 187 #endif // WEBRTC_MODULES_AUDIO_CODING_NETEQ_EXPAND_H_ 188