accelerate.h (3257B)
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 MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_ 12 #define MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_ 13 14 #include <stddef.h> 15 #include <stdint.h> 16 17 #include "modules/audio_coding/neteq/time_stretch.h" 18 19 namespace webrtc { 20 21 class AudioMultiVector; 22 class BackgroundNoise; 23 24 // This class implements the Accelerate operation. Most of the work is done 25 // in the base class TimeStretch, which is shared with the PreemptiveExpand 26 // operation. In the Accelerate class, the operations that are specific to 27 // Accelerate are implemented. 28 class Accelerate : public TimeStretch { 29 public: 30 Accelerate(int sample_rate_hz, 31 size_t num_channels, 32 const BackgroundNoise& background_noise) 33 : TimeStretch(sample_rate_hz, num_channels, background_noise) {} 34 35 Accelerate(const Accelerate&) = delete; 36 Accelerate& operator=(const Accelerate&) = delete; 37 38 // This method performs the actual Accelerate operation. The samples are 39 // read from `input`, of length `input_length` elements, and are written to 40 // `output`. The number of samples removed through time-stretching is 41 // is provided in the output `length_change_samples`. The method returns 42 // the outcome of the operation as an enumerator value. If `fast_accelerate` 43 // is true, the algorithm will relax the requirements on finding strong 44 // correlations, and may remove multiple pitch periods if possible. 45 ReturnCodes Process(const int16_t* input, 46 size_t input_length, 47 bool fast_accelerate, 48 AudioMultiVector* output, 49 size_t* length_change_samples); 50 51 protected: 52 // Sets the parameters `best_correlation` and `peak_index` to suitable 53 // values when the signal contains no active speech. 54 void SetParametersForPassiveSpeech(size_t len, 55 int16_t* best_correlation, 56 size_t* peak_index) const override; 57 58 // Checks the criteria for performing the time-stretching operation and, 59 // if possible, performs the time-stretching. 60 ReturnCodes CheckCriteriaAndStretch(const int16_t* input, 61 size_t input_length, 62 size_t peak_index, 63 int16_t best_correlation, 64 bool active_speech, 65 bool fast_mode, 66 AudioMultiVector* output) const override; 67 }; 68 69 struct AccelerateFactory { 70 AccelerateFactory() {} 71 virtual ~AccelerateFactory() {} 72 73 virtual Accelerate* Create(int sample_rate_hz, 74 size_t num_channels, 75 const BackgroundNoise& background_noise) const; 76 }; 77 78 } // namespace webrtc 79 #endif // MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_