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_ACCELERATE_H_ 12 #define WEBRTC_MODULES_AUDIO_CODING_NETEQ_ACCELERATE_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/modules/audio_coding/neteq/time_stretch.h" 19 #include "webrtc/typedefs.h" 20 21 namespace webrtc { 22 23 // Forward declarations. 24 class BackgroundNoise; 25 26 // This class implements the Accelerate operation. Most of the work is done 27 // in the base class TimeStretch, which is shared with the PreemptiveExpand 28 // operation. In the Accelerate class, the operations that are specific to 29 // Accelerate are implemented. 30 class Accelerate : public TimeStretch { 31 public: Accelerate(int sample_rate_hz,size_t num_channels,const BackgroundNoise & background_noise)32 Accelerate(int sample_rate_hz, size_t num_channels, 33 const BackgroundNoise& background_noise) 34 : TimeStretch(sample_rate_hz, num_channels, background_noise) { 35 } 36 37 // This method performs the actual Accelerate operation. The samples are 38 // read from |input|, of length |input_length| elements, and are written to 39 // |output|. The number of samples removed through time-stretching is 40 // is provided in the output |length_change_samples|. The method returns 41 // the outcome of the operation as an enumerator value. If |fast_accelerate| 42 // is true, the algorithm will relax the requirements on finding strong 43 // correlations, and may remove multiple pitch periods if possible. 44 ReturnCodes Process(const int16_t* input, 45 size_t input_length, 46 bool fast_accelerate, 47 AudioMultiVector* output, 48 size_t* length_change_samples); 49 50 protected: 51 // Sets the parameters |best_correlation| and |peak_index| to suitable 52 // values when the signal contains no active speech. 53 void SetParametersForPassiveSpeech(size_t len, 54 int16_t* best_correlation, 55 size_t* peak_index) const override; 56 57 // Checks the criteria for performing the time-stretching operation and, 58 // if possible, performs the time-stretching. 59 ReturnCodes CheckCriteriaAndStretch(const int16_t* input, 60 size_t input_length, 61 size_t peak_index, 62 int16_t best_correlation, 63 bool active_speech, 64 bool fast_mode, 65 AudioMultiVector* output) const override; 66 67 private: 68 RTC_DISALLOW_COPY_AND_ASSIGN(Accelerate); 69 }; 70 71 struct AccelerateFactory { AccelerateFactoryAccelerateFactory72 AccelerateFactory() {} ~AccelerateFactoryAccelerateFactory73 virtual ~AccelerateFactory() {} 74 75 virtual Accelerate* Create(int sample_rate_hz, 76 size_t num_channels, 77 const BackgroundNoise& background_noise) const; 78 }; 79 80 } // namespace webrtc 81 #endif // WEBRTC_MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_ 82