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 "modules/audio_coding/neteq/accelerate.h"
12
13 #include "common_audio/signal_processing/include/signal_processing_library.h"
14
15 namespace webrtc {
16
Process(const int16_t * input,size_t input_length,bool fast_accelerate,AudioMultiVector * output,size_t * length_change_samples)17 Accelerate::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
SetParametersForPassiveSpeech(size_t,int16_t * best_correlation,size_t *) const35 void 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
CheckCriteriaAndStretch(const int16_t * input,size_t input_length,size_t peak_index,int16_t best_correlation,bool active_speech,bool fast_mode,AudioMultiVector * output) const43 Accelerate::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
Create(int sample_rate_hz,size_t num_channels,const BackgroundNoise & background_noise) const94 Accelerate* 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