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_DTMF_TONE_GENERATOR_H_
12#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_TONE_GENERATOR_H_
13
14
15#include "webrtc/base/constructormagic.h"
16#include "webrtc/modules/audio_coding/neteq/audio_multi_vector.h"
17#include "webrtc/typedefs.h"
18
19namespace webrtc {
20
21// This class provides a generator for DTMF tones.
22class DtmfToneGenerator {
23 public:
24  enum ReturnCodes {
25    kNotInitialized = -1,
26    kParameterError = -2,
27  };
28
29  DtmfToneGenerator();
30  virtual ~DtmfToneGenerator() {}
31  virtual int Init(int fs, int event, int attenuation);
32  virtual void Reset();
33  virtual int Generate(int num_samples, AudioMultiVector* output);
34  virtual bool initialized() const { return initialized_; }
35
36 private:
37  static const int kCoeff1[4][16];  // 1st oscillator model coefficient table.
38  static const int kCoeff2[4][16];  // 2nd oscillator model coefficient table.
39  static const int kInitValue1[4][16];  // Initialization for 1st oscillator.
40  static const int kInitValue2[4][16];  // Initialization for 2nd oscillator.
41  static const int kAmplitude[37];  // Amplitude for 0 through -36 dBm0.
42  static const int16_t kAmpMultiplier = 23171;  // 3 dB attenuation (in Q15).
43
44  bool initialized_;            // True if generator is initialized properly.
45  int coeff1_;                  // 1st oscillator coefficient for this event.
46  int coeff2_;                  // 2nd oscillator coefficient for this event.
47  int amplitude_;               // Amplitude for this event.
48  int16_t sample_history1_[2];  // Last 2 samples for the 1st oscillator.
49  int16_t sample_history2_[2];  // Last 2 samples for the 2nd oscillator.
50
51  DISALLOW_COPY_AND_ASSIGN(DtmfToneGenerator);
52};
53
54}  // namespace webrtc
55#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_TONE_GENERATOR_H_
56