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
14 #include "api/array_view.h"
15 #include "modules/audio_coding/neteq/audio_multi_vector.h"
16
17 namespace webrtc {
18
Process(const int16_t * input,size_t input_length,bool fast_accelerate,AudioMultiVector * output,size_t * length_change_samples)19 Accelerate::ReturnCodes Accelerate::Process(const int16_t* input,
20 size_t input_length,
21 bool fast_accelerate,
22 AudioMultiVector* output,
23 size_t* length_change_samples) {
24 // Input length must be (almost) 30 ms.
25 static const size_t k15ms = 120; // 15 ms = 120 samples at 8 kHz sample rate.
26 if (num_channels_ == 0 ||
27 input_length / num_channels_ < (2 * k15ms - 1) * fs_mult_) {
28 // Length of input data too short to do accelerate. Simply move all data
29 // from input to output.
30 output->PushBackInterleaved(
31 rtc::ArrayView<const int16_t>(input, input_length));
32 return kError;
33 }
34 return TimeStretch::Process(input, input_length, fast_accelerate, output,
35 length_change_samples);
36 }
37
SetParametersForPassiveSpeech(size_t,int16_t * best_correlation,size_t *) const38 void Accelerate::SetParametersForPassiveSpeech(size_t /*len*/,
39 int16_t* best_correlation,
40 size_t* /*peak_index*/) const {
41 // When the signal does not contain any active speech, the correlation does
42 // not matter. Simply set it to zero.
43 *best_correlation = 0;
44 }
45
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) const46 Accelerate::ReturnCodes Accelerate::CheckCriteriaAndStretch(
47 const int16_t* input,
48 size_t input_length,
49 size_t peak_index,
50 int16_t best_correlation,
51 bool active_speech,
52 bool fast_mode,
53 AudioMultiVector* output) const {
54 // Check for strong correlation or passive speech.
55 // Use 8192 (0.5 in Q14) in fast mode.
56 const int correlation_threshold = fast_mode ? 8192 : kCorrelationThreshold;
57 if ((best_correlation > correlation_threshold) || !active_speech) {
58 // Do accelerate operation by overlap add.
59
60 // Pre-calculate common multiplication with `fs_mult_`.
61 // 120 corresponds to 15 ms.
62 size_t fs_mult_120 = fs_mult_ * 120;
63
64 if (fast_mode) {
65 // Fit as many multiples of `peak_index` as possible in fs_mult_120.
66 // TODO(henrik.lundin) Consider finding multiple correlation peaks and
67 // pick the one with the longest correlation lag in this case.
68 peak_index = (fs_mult_120 / peak_index) * peak_index;
69 }
70
71 RTC_DCHECK_GE(fs_mult_120, peak_index); // Should be handled in Process().
72 // Copy first part; 0 to 15 ms.
73 output->PushBackInterleaved(
74 rtc::ArrayView<const int16_t>(input, fs_mult_120 * num_channels_));
75 // Copy the `peak_index` starting at 15 ms to `temp_vector`.
76 AudioMultiVector temp_vector(num_channels_);
77 temp_vector.PushBackInterleaved(rtc::ArrayView<const int16_t>(
78 &input[fs_mult_120 * num_channels_], peak_index * num_channels_));
79 // Cross-fade `temp_vector` onto the end of `output`.
80 output->CrossFade(temp_vector, peak_index);
81 // Copy the last unmodified part, 15 ms + pitch period until the end.
82 output->PushBackInterleaved(rtc::ArrayView<const int16_t>(
83 &input[(fs_mult_120 + peak_index) * num_channels_],
84 input_length - (fs_mult_120 + peak_index) * num_channels_));
85
86 if (active_speech) {
87 return kSuccess;
88 } else {
89 return kSuccessLowEnergy;
90 }
91 } else {
92 // Accelerate not allowed. Simply move all data from decoded to outData.
93 output->PushBackInterleaved(
94 rtc::ArrayView<const int16_t>(input, input_length));
95 return kNoStretch;
96 }
97 }
98
Create(int sample_rate_hz,size_t num_channels,const BackgroundNoise & background_noise) const99 Accelerate* AccelerateFactory::Create(
100 int sample_rate_hz,
101 size_t num_channels,
102 const BackgroundNoise& background_noise) const {
103 return new Accelerate(sample_rate_hz, num_channels, background_noise);
104 }
105
106 } // namespace webrtc
107