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#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_
12#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_
13
14#include <assert.h>
15
16#include "webrtc/base/constructormagic.h"
17#include "webrtc/modules/audio_coding/neteq/audio_multi_vector.h"
18#include "webrtc/modules/audio_coding/neteq/time_stretch.h"
19#include "webrtc/typedefs.h"
20
21namespace webrtc {
22
23// Forward declarations.
24class BackgroundNoise;
25
26// This class implements the Accelerate operation. Most of the work is done
27// in the base class TimeStretch, which is shared with the PreemptiveExpand
28// operation. In the Accelerate class, the operations that are specific to
29// Accelerate are implemented.
30class Accelerate : public TimeStretch {
31 public:
32  Accelerate(int sample_rate_hz, size_t num_channels,
33             const BackgroundNoise& background_noise)
34      : TimeStretch(sample_rate_hz, num_channels, background_noise) {
35  }
36
37  // This method performs the actual Accelerate operation. The samples are
38  // read from |input|, of length |input_length| elements, and are written to
39  // |output|. The number of samples removed through time-stretching is
40  // is provided in the output |length_change_samples|. The method returns
41  // the outcome of the operation as an enumerator value. If |fast_accelerate|
42  // is true, the algorithm will relax the requirements on finding strong
43  // correlations, and may remove multiple pitch periods if possible.
44  ReturnCodes Process(const int16_t* input,
45                      size_t input_length,
46                      bool fast_accelerate,
47                      AudioMultiVector* output,
48                      size_t* length_change_samples);
49
50 protected:
51  // Sets the parameters |best_correlation| and |peak_index| to suitable
52  // values when the signal contains no active speech.
53  void SetParametersForPassiveSpeech(size_t len,
54                                     int16_t* best_correlation,
55                                     size_t* peak_index) const override;
56
57  // Checks the criteria for performing the time-stretching operation and,
58  // if possible, performs the time-stretching.
59  ReturnCodes CheckCriteriaAndStretch(const int16_t* input,
60                                      size_t input_length,
61                                      size_t peak_index,
62                                      int16_t best_correlation,
63                                      bool active_speech,
64                                      bool fast_mode,
65                                      AudioMultiVector* output) const override;
66
67 private:
68  RTC_DISALLOW_COPY_AND_ASSIGN(Accelerate);
69};
70
71struct AccelerateFactory {
72  AccelerateFactory() {}
73  virtual ~AccelerateFactory() {}
74
75  virtual Accelerate* Create(int sample_rate_hz,
76                             size_t num_channels,
77                             const BackgroundNoise& background_noise) const;
78};
79
80}  // namespace webrtc
81#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_
82