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 ~Accelerate()37 virtual ~Accelerate() {} 38 39 // This method performs the actual Accelerate operation. The samples are 40 // read from |input|, of length |input_length| elements, and are written to 41 // |output|. The number of samples removed through time-stretching is 42 // is provided in the output |length_change_samples|. The method returns 43 // the outcome of the operation as an enumerator value. 44 ReturnCodes Process(const int16_t* input, 45 size_t input_length, 46 AudioMultiVector* output, 47 int16_t* length_change_samples); 48 49 protected: 50 // Sets the parameters |best_correlation| and |peak_index| to suitable 51 // values when the signal contains no active speech. 52 virtual void SetParametersForPassiveSpeech(size_t len, 53 int16_t* best_correlation, 54 int* peak_index) const OVERRIDE; 55 56 // Checks the criteria for performing the time-stretching operation and, 57 // if possible, performs the time-stretching. 58 virtual ReturnCodes CheckCriteriaAndStretch( 59 const int16_t* input, size_t input_length, size_t peak_index, 60 int16_t best_correlation, bool active_speech, 61 AudioMultiVector* output) const OVERRIDE; 62 63 private: 64 DISALLOW_COPY_AND_ASSIGN(Accelerate); 65 }; 66 67 struct AccelerateFactory { AccelerateFactoryAccelerateFactory68 AccelerateFactory() {} ~AccelerateFactoryAccelerateFactory69 virtual ~AccelerateFactory() {} 70 71 virtual Accelerate* Create(int sample_rate_hz, 72 size_t num_channels, 73 const BackgroundNoise& background_noise) const; 74 }; 75 76 } // namespace webrtc 77 #endif // WEBRTC_MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_ 78