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#include "webrtc/modules/audio_coding/neteq/accelerate.h" 12 13#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h" 14 15namespace webrtc { 16 17Accelerate::ReturnCodes Accelerate::Process(const int16_t* input, 18 size_t input_length, 19 bool fast_accelerate, 20 AudioMultiVector* output, 21 size_t* length_change_samples) { 22 // Input length must be (almost) 30 ms. 23 static const size_t k15ms = 120; // 15 ms = 120 samples at 8 kHz sample rate. 24 if (num_channels_ == 0 || 25 input_length / num_channels_ < (2 * k15ms - 1) * fs_mult_) { 26 // Length of input data too short to do accelerate. Simply move all data 27 // from input to output. 28 output->PushBackInterleaved(input, input_length); 29 return kError; 30 } 31 return TimeStretch::Process(input, input_length, fast_accelerate, output, 32 length_change_samples); 33} 34 35void Accelerate::SetParametersForPassiveSpeech(size_t /*len*/, 36 int16_t* best_correlation, 37 size_t* /*peak_index*/) const { 38 // When the signal does not contain any active speech, the correlation does 39 // not matter. Simply set it to zero. 40 *best_correlation = 0; 41} 42 43Accelerate::ReturnCodes Accelerate::CheckCriteriaAndStretch( 44 const int16_t* input, 45 size_t input_length, 46 size_t peak_index, 47 int16_t best_correlation, 48 bool active_speech, 49 bool fast_mode, 50 AudioMultiVector* output) const { 51 // Check for strong correlation or passive speech. 52 // Use 8192 (0.5 in Q14) in fast mode. 53 const int correlation_threshold = fast_mode ? 8192 : kCorrelationThreshold; 54 if ((best_correlation > correlation_threshold) || !active_speech) { 55 // Do accelerate operation by overlap add. 56 57 // Pre-calculate common multiplication with |fs_mult_|. 58 // 120 corresponds to 15 ms. 59 size_t fs_mult_120 = fs_mult_ * 120; 60 61 if (fast_mode) { 62 // Fit as many multiples of |peak_index| as possible in fs_mult_120. 63 // TODO(henrik.lundin) Consider finding multiple correlation peaks and 64 // pick the one with the longest correlation lag in this case. 65 peak_index = (fs_mult_120 / peak_index) * peak_index; 66 } 67 68 assert(fs_mult_120 >= peak_index); // Should be handled in Process(). 69 // Copy first part; 0 to 15 ms. 70 output->PushBackInterleaved(input, fs_mult_120 * num_channels_); 71 // Copy the |peak_index| starting at 15 ms to |temp_vector|. 72 AudioMultiVector temp_vector(num_channels_); 73 temp_vector.PushBackInterleaved(&input[fs_mult_120 * num_channels_], 74 peak_index * num_channels_); 75 // Cross-fade |temp_vector| onto the end of |output|. 76 output->CrossFade(temp_vector, peak_index); 77 // Copy the last unmodified part, 15 ms + pitch period until the end. 78 output->PushBackInterleaved( 79 &input[(fs_mult_120 + peak_index) * num_channels_], 80 input_length - (fs_mult_120 + peak_index) * num_channels_); 81 82 if (active_speech) { 83 return kSuccess; 84 } else { 85 return kSuccessLowEnergy; 86 } 87 } else { 88 // Accelerate not allowed. Simply move all data from decoded to outData. 89 output->PushBackInterleaved(input, input_length); 90 return kNoStretch; 91 } 92} 93 94Accelerate* AccelerateFactory::Create( 95 int sample_rate_hz, 96 size_t num_channels, 97 const BackgroundNoise& background_noise) const { 98 return new Accelerate(sample_rate_hz, num_channels, background_noise); 99} 100 101} // namespace webrtc 102