VoiceKey.h

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/***************************************************************************
 
   Audacity: A Digtial Audio Editor
 
   VoiceKey.h: a class implementing a voice key
 
   (c) 2002-2005  Shane T. Mueller
   Distributed under the terms of the GPL Version 2 or later.
 
***************************************************************************/
#ifndef __AUDACITY_VOICEKEY__
#define __AUDACITY_VOICEKEY__
 
 
#ifndef M_PI
#define  M_PI     3.14159265358979323846  /* pi */
#endif
 
#include "SampleCount.h"
 
class WaveChannel;
 
enum VoiceKeyTypes
  {
    VKT_NONE = 0,
    VKT_ENERGY = 1,
    VKT_SIGN_CHANGES_LOW = 2,
    VKT_SIGN_CHANGES_HIGH = 4,
    VKT_DIRECTION_CHANGES_LOW = 8,
    VKT_DIRECTION_CHANGES_HIGH = 16
  };
 
class VoiceKey {
 
 public:
   VoiceKey();
   ~VoiceKey();
   sampleCount OnForward   (const WaveChannel & t, sampleCount start, sampleCount len);
   sampleCount OnBackward  (const WaveChannel & t, sampleCount start, sampleCount len);
   sampleCount OffForward  (const WaveChannel & t, sampleCount start, sampleCount len);
   sampleCount OffBackward (const WaveChannel & t, sampleCount start, sampleCount len);
 
   void CalibrateNoise(const WaveChannel & t, sampleCount start, sampleCount len);
   void AdjustThreshold(double t);
 
 
   bool AboveThreshold(const WaveChannel & t, sampleCount start,sampleCount len);
 
   void SetKeyType(bool erg, bool scLow, bool scHigh,
                   bool dcLow, bool dcHigh);
 
 private:
 
   double mWindowSize;                 //Size of analysis window, in milliseconds
 
   double mThresholdAdjustment;               //User-accessible sensitivity calibration variable
 
   double mEnergyMean;
   double mEnergySD;
   double mSignChangesMean;
   double mSignChangesSD;
   double mDirectionChangesMean;
   double mDirectionChangesSD;
 
   double mThresholdEnergy;                   // Threshold[*] is equal to [*]Mean + [*]SD * ThresholdAdjustment
   double mThresholdSignChangesLower;
   double mThresholdSignChangesUpper;
   double mThresholdDirectionChangesLower;
   double mThresholdDirectionChangesUpper;
 
   //These determine which statistics should be used.
   bool mUseEnergy;
   bool mUseSignChangesLow;
   bool mUseSignChangesHigh;
   bool mUseDirectionChangesLow;
   bool mUseDirectionChangesHigh;
 
 
   double mSilentWindowSize;           //Time in milliseconds of below-threshold windows required for silence
   double mSignalWindowSize;           //Time in milliseconds of above-threshold windows required for speech
 
   double TestEnergy (const WaveChannel & t, sampleCount start,sampleCount len);
   double TestSignChanges (
      const WaveChannel & t, sampleCount start, sampleCount len);
   double TestDirectionChanges(
      const WaveChannel & t, sampleCount start, sampleCount len);
 
   void TestEnergyUpdate (double & prevErg, int length, const float & drop, const float & add);
   void TestSignChangesUpdate(double & currentsignchanges,int length, const float & a1,
                              const float & a2, const float & z1, const float & z2);
   void TestDirectionChangesUpdate(double & currentdirectionchanges,int length,
                                   int & atrend, const float & a1, const float & a2,
                                   int & ztrend, const float & z1, const float & z2);
 
};
 
 
inline int sgn(int  number){ return (number<0) ? -1: 1;}
 
//This returns a logistic density based on a z-score
// a logistic distn has variance (pi*s)^2/3
 
//inline float inline float logistic(float z){   return fexp(-1 * z/(pi / sqrt(3)) / (1 + pow(fexp(-1 * z(pi / sqrt(3))),2)));}
#endif