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 <assert.h>
14
15 #include "api/array_view.h"
16 #include "modules/audio_coding/neteq/audio_multi_vector.h"
17
18 namespace webrtc {
19
Process(const int16_t * input,size_t input_length,bool fast_accelerate,AudioMultiVector * output,size_t * length_change_samples)20 Accelerate::ReturnCodes Accelerate::Process(const int16_t* input,
21 size_t input_length,
22 bool fast_accelerate,
23 AudioMultiVector* output,
24 size_t* length_change_samples) {
25 // Input length must be (almost) 30 ms.
26 static const size_t k15ms = 120; // 15 ms = 120 samples at 8 kHz sample rate.
27 if (num_channels_ == 0 ||
28 input_length / num_channels_ < (2 * k15ms - 1) * fs_mult_) {
29 // Length of input data too short to do accelerate. Simply move all data
30 // from input to output.
31 output->PushBackInterleaved(
32 rtc::ArrayView<const int16_t>(input, input_length));
33 return kError;
34 }
35 return TimeStretch::Process(input, input_length, fast_accelerate, output,
36 length_change_samples);
37 }
38
SetParametersForPassiveSpeech(size_t,int16_t * best_correlation,size_t *) const39 void Accelerate::SetParametersForPassiveSpeech(size_t /*len*/,
40 int16_t* best_correlation,
41 size_t* /*peak_index*/) const {
42 // When the signal does not contain any active speech, the correlation does
43 // not matter. Simply set it to zero.
44 *best_correlation = 0;
45 }
46
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) const47 Accelerate::ReturnCodes Accelerate::CheckCriteriaAndStretch(
48 const int16_t* input,
49 size_t input_length,
50 size_t peak_index,
51 int16_t best_correlation,
52 bool active_speech,
53 bool fast_mode,
54 AudioMultiVector* output) const {
55 // Check for strong correlation or passive speech.
56 // Use 8192 (0.5 in Q14) in fast mode.
57 const int correlation_threshold = fast_mode ? 8192 : kCorrelationThreshold;
58 if ((best_correlation > correlation_threshold) || !active_speech) {
59 // Do accelerate operation by overlap add.
60
61 // Pre-calculate common multiplication with |fs_mult_|.
62 // 120 corresponds to 15 ms.
63 size_t fs_mult_120 = fs_mult_ * 120;
64
65 if (fast_mode) {
66 // Fit as many multiples of |peak_index| as possible in fs_mult_120.
67 // TODO(henrik.lundin) Consider finding multiple correlation peaks and
68 // pick the one with the longest correlation lag in this case.
69 peak_index = (fs_mult_120 / peak_index) * peak_index;
70 }
71
72 assert(fs_mult_120 >= peak_index); // Should be handled in Process().
73 // Copy first part; 0 to 15 ms.
74 output->PushBackInterleaved(
75 rtc::ArrayView<const int16_t>(input, fs_mult_120 * num_channels_));
76 // Copy the |peak_index| starting at 15 ms to |temp_vector|.
77 AudioMultiVector temp_vector(num_channels_);
78 temp_vector.PushBackInterleaved(rtc::ArrayView<const int16_t>(
79 &input[fs_mult_120 * num_channels_], peak_index * num_channels_));
80 // Cross-fade |temp_vector| onto the end of |output|.
81 output->CrossFade(temp_vector, peak_index);
82 // Copy the last unmodified part, 15 ms + pitch period until the end.
83 output->PushBackInterleaved(rtc::ArrayView<const int16_t>(
84 &input[(fs_mult_120 + peak_index) * num_channels_],
85 input_length - (fs_mult_120 + peak_index) * num_channels_));
86
87 if (active_speech) {
88 return kSuccess;
89 } else {
90 return kSuccessLowEnergy;
91 }
92 } else {
93 // Accelerate not allowed. Simply move all data from decoded to outData.
94 output->PushBackInterleaved(
95 rtc::ArrayView<const int16_t>(input, input_length));
96 return kNoStretch;
97 }
98 }
99
Create(int sample_rate_hz,size_t num_channels,const BackgroundNoise & background_noise) const100 Accelerate* AccelerateFactory::Create(
101 int sample_rate_hz,
102 size_t num_channels,
103 const BackgroundNoise& background_noise) const {
104 return new Accelerate(sample_rate_hz, num_channels, background_noise);
105 }
106
107 } // namespace webrtc
108