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  virtual ~Accelerate() {}
38
39  // This method performs the actual Accelerate operation. The samples are
40  // read from |input|, of length |input_length| elements, and are written to
41  // |output|. The number of samples removed through time-stretching is
42  // is provided in the output |length_change_samples|. The method returns
43  // the outcome of the operation as an enumerator value.
44  ReturnCodes Process(const int16_t* input,
45                      size_t input_length,
46                      AudioMultiVector* output,
47                      int16_t* length_change_samples);
48
49 protected:
50  // Sets the parameters |best_correlation| and |peak_index| to suitable
51  // values when the signal contains no active speech.
52  virtual void SetParametersForPassiveSpeech(size_t len,
53                                             int16_t* best_correlation,
54                                             int* peak_index) const OVERRIDE;
55
56  // Checks the criteria for performing the time-stretching operation and,
57  // if possible, performs the time-stretching.
58  virtual ReturnCodes CheckCriteriaAndStretch(
59      const int16_t* input, size_t input_length, size_t peak_index,
60      int16_t best_correlation, bool active_speech,
61      AudioMultiVector* output) const OVERRIDE;
62
63 private:
64  DISALLOW_COPY_AND_ASSIGN(Accelerate);
65};
66
67struct AccelerateFactory {
68  AccelerateFactory() {}
69  virtual ~AccelerateFactory() {}
70
71  virtual Accelerate* Create(int sample_rate_hz,
72                             size_t num_channels,
73                             const BackgroundNoise& background_noise) const;
74};
75
76}  // namespace webrtc
77#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_ACCELERATE_H_
78