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 MODULES_AUDIO_CODING_NETEQ_DTMF_TONE_GENERATOR_H_
12 #define MODULES_AUDIO_CODING_NETEQ_DTMF_TONE_GENERATOR_H_
13 
14 #include <stddef.h>
15 #include <stdint.h>
16 
17 #include "modules/audio_coding/neteq/audio_multi_vector.h"
18 #include "rtc_base/constructor_magic.h"
19 
20 namespace webrtc {
21 
22 // This class provides a generator for DTMF tones.
23 class DtmfToneGenerator {
24  public:
25   enum ReturnCodes {
26     kNotInitialized = -1,
27     kParameterError = -2,
28   };
29 
30   DtmfToneGenerator();
~DtmfToneGenerator()31   virtual ~DtmfToneGenerator() {}
32   virtual int Init(int fs, int event, int attenuation);
33   virtual void Reset();
34   virtual int Generate(size_t num_samples, AudioMultiVector* output);
35   virtual bool initialized() const;
36 
37  private:
38   static const int kCoeff1[4][16];  // 1st oscillator model coefficient table.
39   static const int kCoeff2[4][16];  // 2nd oscillator model coefficient table.
40   static const int kInitValue1[4][16];  // Initialization for 1st oscillator.
41   static const int kInitValue2[4][16];  // Initialization for 2nd oscillator.
42   static const int kAmplitude[64];      // Amplitude for 0 through -63 dBm0.
43   static const int16_t kAmpMultiplier = 23171;  // 3 dB attenuation (in Q15).
44 
45   bool initialized_;            // True if generator is initialized properly.
46   int coeff1_;                  // 1st oscillator coefficient for this event.
47   int coeff2_;                  // 2nd oscillator coefficient for this event.
48   int amplitude_;               // Amplitude for this event.
49   int16_t sample_history1_[2];  // Last 2 samples for the 1st oscillator.
50   int16_t sample_history2_[2];  // Last 2 samples for the 2nd oscillator.
51 
52   RTC_DISALLOW_COPY_AND_ASSIGN(DtmfToneGenerator);
53 };
54 
55 }  // namespace webrtc
56 #endif  // MODULES_AUDIO_CODING_NETEQ_DTMF_TONE_GENERATOR_H_
57