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_DELAY_PEAK_DETECTOR_H_
12#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_DELAY_PEAK_DETECTOR_H_
13
14#include <string.h>  // size_t
15
16#include <list>
17
18#include "webrtc/base/constructormagic.h"
19
20namespace webrtc {
21
22class DelayPeakDetector {
23 public:
24  DelayPeakDetector();
25  virtual ~DelayPeakDetector();
26  virtual void Reset();
27
28  // Notifies the DelayPeakDetector of how much audio data is carried in each
29  // packet.
30  virtual void SetPacketAudioLength(int length_ms);
31
32  // Returns true if peak-mode is active. That is, delay peaks were observed
33  // recently.
34  virtual bool peak_found();
35
36  // Calculates and returns the maximum delay peak height. Returns -1 if no
37  // delay peaks have been observed recently. The unit is number of packets.
38  virtual int MaxPeakHeight() const;
39
40  // Calculates and returns the maximum delay peak distance in ms.
41  // Returns -1 if no delay peaks have been observed recently.
42  virtual int MaxPeakPeriod() const;
43
44  // Updates the DelayPeakDetector with a new inter-arrival time (in packets)
45  // and the current target buffer level (needed to decide if a peak is observed
46  // or not). Returns true if peak-mode is active, false if not.
47  virtual bool Update(int inter_arrival_time, int target_level);
48
49  // Increments the |peak_period_counter_ms_| with |inc_ms|. Only increments
50  // the counter if it is non-negative. A negative denotes that no peak has
51  // been observed.
52  virtual void IncrementCounter(int inc_ms);
53
54 private:
55  static const size_t kMaxNumPeaks = 8;
56  static const size_t kMinPeaksToTrigger = 2;
57  static const int kPeakHeightMs = 78;
58  static const int kMaxPeakPeriodMs = 10000;
59
60  typedef struct {
61    int period_ms;
62    int peak_height_packets;
63  } Peak;
64
65  bool CheckPeakConditions();
66
67  std::list<Peak> peak_history_;
68  bool peak_found_;
69  int peak_detection_threshold_;
70  int peak_period_counter_ms_;
71
72  RTC_DISALLOW_COPY_AND_ASSIGN(DelayPeakDetector);
73};
74
75}  // namespace webrtc
76#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_DELAY_PEAK_DETECTOR_H_
77