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(
18    const int16_t* input,
19    size_t input_length,
20    AudioMultiVector* output,
21    int16_t* length_change_samples) {
22  // Input length must be (almost) 30 ms.
23  static const int k15ms = 120;  // 15 ms = 120 samples at 8 kHz sample rate.
24  if (num_channels_ == 0 || static_cast<int>(input_length) / num_channels_ <
25      (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, output,
32                              length_change_samples);
33}
34
35void Accelerate::SetParametersForPassiveSpeech(size_t /*len*/,
36                                               int16_t* best_correlation,
37                                               int* /*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, size_t input_length, size_t peak_index,
45    int16_t best_correlation, bool active_speech,
46    AudioMultiVector* output) const {
47  // Check for strong correlation or passive speech.
48  if ((best_correlation > kCorrelationThreshold) || !active_speech) {
49    // Do accelerate operation by overlap add.
50
51    // Pre-calculate common multiplication with |fs_mult_|.
52    // 120 corresponds to 15 ms.
53    size_t fs_mult_120 = fs_mult_ * 120;
54
55    assert(fs_mult_120 >= peak_index);  // Should be handled in Process().
56    // Copy first part; 0 to 15 ms.
57    output->PushBackInterleaved(input, fs_mult_120 * num_channels_);
58    // Copy the |peak_index| starting at 15 ms to |temp_vector|.
59    AudioMultiVector temp_vector(num_channels_);
60    temp_vector.PushBackInterleaved(&input[fs_mult_120 * num_channels_],
61                                    peak_index * num_channels_);
62    // Cross-fade |temp_vector| onto the end of |output|.
63    output->CrossFade(temp_vector, peak_index);
64    // Copy the last unmodified part, 15 ms + pitch period until the end.
65    output->PushBackInterleaved(
66        &input[(fs_mult_120 + peak_index) * num_channels_],
67        input_length - (fs_mult_120 + peak_index) * num_channels_);
68
69    if (active_speech) {
70      return kSuccess;
71    } else {
72      return kSuccessLowEnergy;
73    }
74  } else {
75    // Accelerate not allowed. Simply move all data from decoded to outData.
76    output->PushBackInterleaved(input, input_length);
77    return kNoStretch;
78  }
79}
80
81Accelerate* AccelerateFactory::Create(
82    int sample_rate_hz,
83    size_t num_channels,
84    const BackgroundNoise& background_noise) const {
85  return new Accelerate(sample_rate_hz, num_channels, background_noise);
86}
87
88}  // namespace webrtc
89