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 
19 namespace webrtc {
20 
21 // This class provides a generator for DTMF tones.
22 class DtmfToneGenerator {
23  public:
24   enum ReturnCodes {
25     kNotInitialized = -1,
26     kParameterError = -2,
27   };
28 
29   DtmfToneGenerator();
~DtmfToneGenerator()30   virtual ~DtmfToneGenerator() {}
31   virtual int Init(int fs, int event, int attenuation);
32   virtual void Reset();
33   virtual int Generate(size_t num_samples, AudioMultiVector* output);
34   virtual bool initialized() const;
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   RTC_DISALLOW_COPY_AND_ASSIGN(DtmfToneGenerator);
52 };
53 
54 }  // namespace webrtc
55 #endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_TONE_GENERATOR_H_
56