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/base/scoped_ptr.h" 18 #include "webrtc/modules/audio_coding/neteq/audio_multi_vector.h" 19 #include "webrtc/typedefs.h" 20 21 namespace webrtc { 22 23 // Forward declarations. 24 class BackgroundNoise; 25 class RandomVector; 26 class StatisticsCalculator; 27 class SyncBuffer; 28 29 // This class handles extrapolation of audio data from the sync_buffer to 30 // produce packet-loss concealment. 31 // TODO(hlundin): Refactor this class to divide the long methods into shorter 32 // ones. 33 class Expand { 34 public: 35 Expand(BackgroundNoise* background_noise, 36 SyncBuffer* sync_buffer, 37 RandomVector* random_vector, 38 StatisticsCalculator* statistics, 39 int fs, 40 size_t num_channels); 41 42 virtual ~Expand(); 43 44 // Resets the object. 45 virtual void Reset(); 46 47 // The main method to produce concealment data. The data is appended to the 48 // end of |output|. 49 virtual int Process(AudioMultiVector* output); 50 51 // Prepare the object to do extra expansion during normal operation following 52 // a period of expands. 53 virtual void SetParametersForNormalAfterExpand(); 54 55 // Prepare the object to do extra expansion during merge operation following 56 // a period of expands. 57 virtual void SetParametersForMergeAfterExpand(); 58 59 // Returns the mute factor for |channel|. MuteFactor(size_t channel)60 int16_t MuteFactor(size_t channel) { 61 assert(channel < num_channels_); 62 return channel_parameters_[channel].mute_factor; 63 } 64 65 // Accessors and mutators. 66 virtual size_t overlap_length() const; max_lag()67 size_t max_lag() const { return max_lag_; } 68 69 protected: 70 static const int kMaxConsecutiveExpands = 200; 71 void GenerateRandomVector(int16_t seed_increment, 72 size_t length, 73 int16_t* random_vector); 74 75 void GenerateBackgroundNoise(int16_t* random_vector, 76 size_t channel, 77 int mute_slope, 78 bool too_many_expands, 79 size_t num_noise_samples, 80 int16_t* buffer); 81 82 // Initializes member variables at the beginning of an expand period. 83 void InitializeForAnExpandPeriod(); 84 85 bool TooManyExpands(); 86 87 // Analyzes the signal history in |sync_buffer_|, and set up all parameters 88 // necessary to produce concealment data. 89 void AnalyzeSignal(int16_t* random_vector); 90 91 RandomVector* const random_vector_; 92 SyncBuffer* const sync_buffer_; 93 bool first_expand_; 94 const int fs_hz_; 95 const size_t num_channels_; 96 int consecutive_expands_; 97 98 private: 99 static const size_t kUnvoicedLpcOrder = 6; 100 static const size_t kNumCorrelationCandidates = 3; 101 static const size_t kDistortionLength = 20; 102 static const size_t kLpcAnalysisLength = 160; 103 static const size_t kMaxSampleRate = 48000; 104 static const int kNumLags = 3; 105 106 struct ChannelParameters { 107 ChannelParameters(); 108 int16_t mute_factor; 109 int16_t ar_filter[kUnvoicedLpcOrder + 1]; 110 int16_t ar_filter_state[kUnvoicedLpcOrder]; 111 int16_t ar_gain; 112 int16_t ar_gain_scale; 113 int16_t voice_mix_factor; /* Q14 */ 114 int16_t current_voice_mix_factor; /* Q14 */ 115 AudioVector expand_vector0; 116 AudioVector expand_vector1; 117 bool onset; 118 int mute_slope; /* Q20 */ 119 }; 120 121 // Calculate the auto-correlation of |input|, with length |input_length| 122 // samples. The correlation is calculated from a downsampled version of 123 // |input|, and is written to |output|. The scale factor is written to 124 // |output_scale|. 125 void Correlation(const int16_t* input, 126 size_t input_length, 127 int16_t* output, 128 int* output_scale) const; 129 130 void UpdateLagIndex(); 131 132 BackgroundNoise* const background_noise_; 133 StatisticsCalculator* const statistics_; 134 const size_t overlap_length_; 135 size_t max_lag_; 136 size_t expand_lags_[kNumLags]; 137 int lag_index_direction_; 138 int current_lag_index_; 139 bool stop_muting_; 140 size_t expand_duration_samples_; 141 rtc::scoped_ptr<ChannelParameters[]> channel_parameters_; 142 143 RTC_DISALLOW_COPY_AND_ASSIGN(Expand); 144 }; 145 146 struct ExpandFactory { ExpandFactoryExpandFactory147 ExpandFactory() {} ~ExpandFactoryExpandFactory148 virtual ~ExpandFactory() {} 149 150 virtual Expand* Create(BackgroundNoise* background_noise, 151 SyncBuffer* sync_buffer, 152 RandomVector* random_vector, 153 StatisticsCalculator* statistics, 154 int fs, 155 size_t num_channels) const; 156 }; 157 158 } // namespace webrtc 159 #endif // WEBRTC_MODULES_AUDIO_CODING_NETEQ_EXPAND_H_ 160