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_PREEMPTIVE_EXPAND_H_
12#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_PREEMPTIVE_EXPAND_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 PreemptiveExpand operation. Most of the work is
27// done in the base class TimeStretch, which is shared with the Accelerate
28// operation. In the PreemptiveExpand class, the operations that are specific to
29// PreemptiveExpand are implemented.
30class PreemptiveExpand : public TimeStretch {
31 public:
32  PreemptiveExpand(int sample_rate_hz,
33                   size_t num_channels,
34                   const BackgroundNoise& background_noise,
35                   int overlap_samples)
36      : TimeStretch(sample_rate_hz, num_channels, background_noise),
37        old_data_length_per_channel_(-1),
38        overlap_samples_(overlap_samples) {
39  }
40
41  virtual ~PreemptiveExpand() {}
42
43  // This method performs the actual PreemptiveExpand operation. The samples are
44  // read from |input|, of length |input_length| elements, and are written to
45  // |output|. The number of samples added through time-stretching is
46  // is provided in the output |length_change_samples|. The method returns
47  // the outcome of the operation as an enumerator value.
48  ReturnCodes Process(const int16_t *pw16_decoded,
49                      int len,
50                      int old_data_len,
51                      AudioMultiVector* output,
52                      int16_t* length_change_samples);
53
54 protected:
55  // Sets the parameters |best_correlation| and |peak_index| to suitable
56  // values when the signal contains no active speech.
57  virtual void SetParametersForPassiveSpeech(size_t len,
58                                             int16_t* w16_bestCorr,
59                                             int* w16_bestIndex) const;
60
61  // Checks the criteria for performing the time-stretching operation and,
62  // if possible, performs the time-stretching.
63  virtual ReturnCodes CheckCriteriaAndStretch(
64      const int16_t *pw16_decoded, size_t len, size_t w16_bestIndex,
65      int16_t w16_bestCorr, bool w16_VAD,
66      AudioMultiVector* output) const;
67
68 private:
69  int old_data_length_per_channel_;
70  int overlap_samples_;
71
72  DISALLOW_COPY_AND_ASSIGN(PreemptiveExpand);
73};
74
75struct PreemptiveExpandFactory {
76  PreemptiveExpandFactory() {}
77  virtual ~PreemptiveExpandFactory() {}
78
79  virtual PreemptiveExpand* Create(
80      int sample_rate_hz,
81      size_t num_channels,
82      const BackgroundNoise& background_noise,
83      int overlap_samples) const;
84};
85
86}  // namespace webrtc
87#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_PREEMPTIVE_EXPAND_H_
88