preemptive_expand.h (3486B)
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_PREEMPTIVE_EXPAND_H_ 12 #define MODULES_AUDIO_CODING_NETEQ_PREEMPTIVE_EXPAND_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 PreemptiveExpand operation. Most of the work is 25 // done in the base class TimeStretch, which is shared with the Accelerate 26 // operation. In the PreemptiveExpand class, the operations that are specific to 27 // PreemptiveExpand are implemented. 28 class PreemptiveExpand : public TimeStretch { 29 public: 30 PreemptiveExpand(int sample_rate_hz, 31 size_t num_channels, 32 const BackgroundNoise& background_noise, 33 size_t overlap_samples) 34 : TimeStretch(sample_rate_hz, num_channels, background_noise), 35 old_data_length_per_channel_(0), 36 overlap_samples_(overlap_samples) {} 37 38 PreemptiveExpand(const PreemptiveExpand&) = delete; 39 PreemptiveExpand& operator=(const PreemptiveExpand&) = delete; 40 41 // This method performs the actual PreemptiveExpand operation. The samples are 42 // read from `input`, of length `input_length` elements, and are written to 43 // `output`. The number of samples added through time-stretching is 44 // is provided in the output `length_change_samples`. The method returns 45 // the outcome of the operation as an enumerator value. 46 ReturnCodes Process(const int16_t* pw16_decoded, 47 size_t len, 48 size_t old_data_len, 49 AudioMultiVector* output, 50 size_t* length_change_samples); 51 52 protected: 53 // Sets the parameters `best_correlation` and `peak_index` to suitable 54 // values when the signal contains no active speech. 55 void SetParametersForPassiveSpeech(size_t input_length, 56 int16_t* best_correlation, 57 size_t* peak_index) const override; 58 59 // Checks the criteria for performing the time-stretching operation and, 60 // if possible, performs the time-stretching. 61 ReturnCodes CheckCriteriaAndStretch(const int16_t* input, 62 size_t input_length, 63 size_t peak_index, 64 int16_t best_correlation, 65 bool active_speech, 66 bool /*fast_mode*/, 67 AudioMultiVector* output) const override; 68 69 private: 70 size_t old_data_length_per_channel_; 71 size_t overlap_samples_; 72 }; 73 74 struct PreemptiveExpandFactory { 75 PreemptiveExpandFactory() {} 76 virtual ~PreemptiveExpandFactory() {} 77 78 virtual PreemptiveExpand* Create(int sample_rate_hz, 79 size_t num_channels, 80 const BackgroundNoise& background_noise, 81 size_t overlap_samples) const; 82 }; 83 84 } // namespace webrtc 85 #endif // MODULES_AUDIO_CODING_NETEQ_PREEMPTIVE_EXPAND_H_