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/preemptive_expand.h" 12 13#include <algorithm> // min, max 14 15#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h" 16 17namespace webrtc { 18 19PreemptiveExpand::ReturnCodes PreemptiveExpand::Process( 20 const int16_t* input, 21 size_t input_length, 22 size_t old_data_length, 23 AudioMultiVector* output, 24 size_t* length_change_samples) { 25 old_data_length_per_channel_ = old_data_length; 26 // Input length must be (almost) 30 ms. 27 // Also, the new part must be at least |overlap_samples_| elements. 28 static const size_t k15ms = 120; // 15 ms = 120 samples at 8 kHz sample rate. 29 if (num_channels_ == 0 || 30 input_length / num_channels_ < (2 * k15ms - 1) * fs_mult_ || 31 old_data_length >= input_length / num_channels_ - overlap_samples_) { 32 // Length of input data too short to do preemptive expand. Simply move all 33 // data from input to output. 34 output->PushBackInterleaved(input, input_length); 35 return kError; 36 } 37 const bool kFastMode = false; // Fast mode is not available for PE Expand. 38 return TimeStretch::Process(input, input_length, kFastMode, output, 39 length_change_samples); 40} 41 42void PreemptiveExpand::SetParametersForPassiveSpeech(size_t len, 43 int16_t* best_correlation, 44 size_t* peak_index) const { 45 // When the signal does not contain any active speech, the correlation does 46 // not matter. Simply set it to zero. 47 *best_correlation = 0; 48 49 // For low energy expansion, the new data can be less than 15 ms, 50 // but we must ensure that best_correlation is not larger than the length of 51 // the new data. 52 // but we must ensure that best_correlation is not larger than the new data. 53 *peak_index = std::min(*peak_index, 54 len - old_data_length_per_channel_); 55} 56 57PreemptiveExpand::ReturnCodes PreemptiveExpand::CheckCriteriaAndStretch( 58 const int16_t* input, 59 size_t input_length, 60 size_t peak_index, 61 int16_t best_correlation, 62 bool active_speech, 63 bool /*fast_mode*/, 64 AudioMultiVector* output) const { 65 // Pre-calculate common multiplication with |fs_mult_|. 66 // 120 corresponds to 15 ms. 67 size_t fs_mult_120 = static_cast<size_t>(fs_mult_ * 120); 68 // Check for strong correlation (>0.9 in Q14) and at least 15 ms new data, 69 // or passive speech. 70 if (((best_correlation > kCorrelationThreshold) && 71 (old_data_length_per_channel_ <= fs_mult_120)) || 72 !active_speech) { 73 // Do accelerate operation by overlap add. 74 75 // Set length of the first part, not to be modified. 76 size_t unmodified_length = std::max(old_data_length_per_channel_, 77 fs_mult_120); 78 // Copy first part, including cross-fade region. 79 output->PushBackInterleaved( 80 input, (unmodified_length + peak_index) * num_channels_); 81 // Copy the last |peak_index| samples up to 15 ms to |temp_vector|. 82 AudioMultiVector temp_vector(num_channels_); 83 temp_vector.PushBackInterleaved( 84 &input[(unmodified_length - peak_index) * num_channels_], 85 peak_index * num_channels_); 86 // Cross-fade |temp_vector| onto the end of |output|. 87 output->CrossFade(temp_vector, peak_index); 88 // Copy the last unmodified part, 15 ms + pitch period until the end. 89 output->PushBackInterleaved( 90 &input[unmodified_length * num_channels_], 91 input_length - unmodified_length * num_channels_); 92 93 if (active_speech) { 94 return kSuccess; 95 } else { 96 return kSuccessLowEnergy; 97 } 98 } else { 99 // Accelerate not allowed. Simply move all data from decoded to outData. 100 output->PushBackInterleaved(input, input_length); 101 return kNoStretch; 102 } 103} 104 105PreemptiveExpand* PreemptiveExpandFactory::Create( 106 int sample_rate_hz, 107 size_t num_channels, 108 const BackgroundNoise& background_noise, 109 size_t overlap_samples) const { 110 return new PreemptiveExpand( 111 sample_rate_hz, num_channels, background_noise, overlap_samples); 112} 113 114} // namespace webrtc 115