Added dB - linear amplitude conversion macros.

src/Audacity.h

@@ -152,8 +152,11 @@ void QuitAudacity();
    #endif
 #endif
 
-// This macro is used widely, so declared here.
+// These macros are used widely, so declared here.
 #define QUANTIZED_TIME(time, rate) ((double)((sampleCount)floor(((double)(time) * (rate)) + 0.5))) / (rate)
+// dB - linear amplitude convesions
+#define DB_TO_LINEAR(x) pow(10.0, x / 20.0)
+#define LINEAR_TO_DB(x) 20.0 * log10(x)
 
 // Marks strings for extraction only...must use wxGetTranslation() to translate.
 #define XO(s) wxT(s)

src/Envelope.cpp

@@ -185,7 +185,7 @@ double Envelope::toDB(double value)
    double sign = (value >= 0 ? 1 : -1);
 
    wxASSERT( dBRange > 0 );
-   double db = 20 * log10(fabs(value));
+   double db = LINEAR_TO_DB(fabs(value));
    double val = (db + dBRange) / dBRange;
 
    val = Limit( 0.0, val, 1.0 );

src/TrackArtist.cpp

@@ -706,7 +706,7 @@ void TrackArtist::UpdateVRuler(Track *t, wxRect & rect)
             wt->SetDisplay(WaveTrack::WaveformDisplay); // this makes the last display not WaveformDBDisplay
             float sign = (min >= 0 ? 1 : -1);
             if (min != 0.) {
-               min = pow(10., (fabs(min)*mdBrange - mdBrange)/20.0);
+               min = DB_TO_LINEAR(fabs(min)*mdBrange - mdBrange);
                if (min < 0.0)
                   min = 0.0;
                min *= sign;
@@ -714,7 +714,7 @@ void TrackArtist::UpdateVRuler(Track *t, wxRect & rect)
             sign = (max >= 0 ? 1 : -1);
 
             if (max != 0.) {
-               max = pow(10., (fabs(max)*mdBrange - mdBrange)/20.0);
+               max = DB_TO_LINEAR(fabs(max)*mdBrange - mdBrange);
                if (max < 0.0)
                   max = 0.0;
                max *= sign;
@@ -744,7 +744,7 @@ void TrackArtist::UpdateVRuler(Track *t, wxRect & rect)
             wt->SetDisplay(WaveTrack::WaveformDBDisplay); // this makes the last display not WaveformDisplay
             float sign = (min >= 0 ? 1 : -1);
             if (min != 0.) {
-               min = (20.0 * log10(fabs(min)) + mdBrange) / mdBrange;
+               min = (LINEAR_TO_DB(fabs(min)) + mdBrange) / mdBrange;
                if (min < 0.0)
                   min = 0.0;
                min *= sign;
@@ -752,7 +752,7 @@ void TrackArtist::UpdateVRuler(Track *t, wxRect & rect)
             sign = (max >= 0 ? 1 : -1);
 
             if (max != 0.) {
-               max = (20.0 * log10(fabs(max)) + mdBrange) / mdBrange;
+               max = (LINEAR_TO_DB(fabs(max)) + mdBrange) / mdBrange;
                if (max < 0.0)
                   max = 0.0;
                max *= sign;
@@ -900,7 +900,7 @@ int GetWaveYPos(float value, float min, float max,
       float sign = (value >= 0 ? 1 : -1);
 
       if (value != 0.) {
-         float db = 20.0 * log10(fabs(value));
+         float db = LINEAR_TO_DB(fabs(value));
          value = (db + dBr) / dBr;
          if (!outer) {
             value -= 0.5;
@@ -941,7 +941,7 @@ float FromDB(float value, double dBRange)
       return 0;
 
    double sign = (value >= 0 ? 1 : -1);
-   return pow(10.0, ((fabs(value) * dBRange) - dBRange) / 20.0)*sign;
+   return DB_TO_LINEAR((fabs(value) * dBRange) - dBRange) * sign;
 }
 
 float ValueOfPixel(int yy, int height, bool offset,
@@ -3188,8 +3188,8 @@ void TrackArtist::DrawTimeTrack(TimeTrack *track,
    if(track->GetDisplayLog()) {
       // MB: silly way to undo the work of GetWaveYPos while still getting a logarithmic scale
       double dBRange = gPrefs->Read(wxT("/GUI/EnvdBRange"), ENV_DB_RANGE);
-      lower = 20.0 * log10(std::max(1.0e-7, lower)) / dBRange + 1.0;
+      lower = LINEAR_TO_DB(std::max(1.0e-7, lower)) / dBRange + 1.0;
-      upper = 20.0 * log10(std::max(1.0e-7, upper)) / dBRange + 1.0;
+      upper = LINEAR_TO_DB(std::max(1.0e-7, upper)) / dBRange + 1.0;
    }
    track->GetEnvelope()->DrawPoints(dc, envRect, zoomInfo,
                track->GetDisplayLog(), lower, upper);

src/TrackPanel.cpp

@@ -3810,8 +3810,8 @@ void TrackPanel::ForwardEventToTimeTrackEnvelope(wxMouseEvent & event)
    if(ptimetrack->GetDisplayLog()) {
       // MB: silly way to undo the work of GetWaveYPos while still getting a logarithmic scale
       double dBRange = gPrefs->Read(wxT("/GUI/EnvdBRange"), ENV_DB_RANGE);
-      lower = 20.0 * log10(std::max(1.0e-7, lower)) / dBRange + 1.0;
+      lower = LINEAR_TO_DB(std::max(1.0e-7, lower)) / dBRange + 1.0;
-      upper = 20.0 * log10(std::max(1.0e-7, upper)) / dBRange + 1.0;
+      upper = LINEAR_TO_DB(std::max(1.0e-7, upper)) / dBRange + 1.0;
    }
    bool needUpdate =
       pspeedenvelope->MouseEvent(

src/effects/Amplify.cpp

@@ -65,7 +65,7 @@ END_EVENT_TABLE()
 EffectAmplify::EffectAmplify()
 {
    mAmp = DEF_Amp;
-   mRatio = pow(10.0, mAmp / 20.0);
+   mRatio = DB_TO_LINEAR(mAmp);
    mRatioClip = 0.0;
    mCanClip = false;
    mPeak = 0.0;
@@ -235,8 +235,8 @@ void EffectAmplify::PopulateOrExchange(ShuttleGui & S)
       S.StartMultiColumn(2, wxCENTER);
       {
          FloatingPointValidator<double> vldNewPeak(precission, &mNewPeak, NUM_VAL_ONE_TRAILING_ZERO);
-         double minAmp = MIN_Amp + (20.0 * log10(mPeak));
+         double minAmp = MIN_Amp + LINEAR_TO_DB(mPeak);
-         double maxAmp = MAX_Amp + (20.0 * log10(mPeak));
+         double maxAmp = MAX_Amp + LINEAR_TO_DB(mPeak);
 
          // min and max need same precision as what we're validating (bug 963)
          minAmp = Internat::CompatibleToDouble(Internat::ToString(minAmp, precission));
@@ -268,17 +268,17 @@ void EffectAmplify::PopulateOrExchange(ShuttleGui & S)
 bool EffectAmplify::TransferDataToWindow()
 {
    // limit range of gain
-   double dBInit = 20.0*log10(mRatio);
+   double dBInit = LINEAR_TO_DB(mRatio);
    double dB = TrapDouble(dBInit, MIN_Amp, MAX_Amp);
    if (dB != dBInit)
-      mRatio = pow(10.0, dB / 20.0);
+      mRatio = DB_TO_LINEAR(dB);
 
-   mAmp = 20.0 * log10(mRatio);
+   mAmp = LINEAR_TO_DB(mRatio);
    mAmpT->GetValidator()->TransferToWindow();
 
    mAmpS->SetValue((int) (mAmp * SCL_Amp + 0.5f));
 
-   mNewPeak = 20.0 * log10(mRatio * mPeak);
+   mNewPeak = LINEAR_TO_DB(mRatio * mPeak);
    mNewPeakT->GetValidator()->TransferToWindow();
 
    mClip->SetValue(mCanClip);
@@ -295,7 +295,7 @@ bool EffectAmplify::TransferDataFromWindow()
       return false;
    }
 
-   mRatio = pow(10.0, TrapDouble(mAmp * SCL_Amp, MIN_Amp * SCL_Amp, MAX_Amp * SCL_Amp) / (20.0 * SCL_Amp));
+   mRatio = DB_TO_LINEAR(TrapDouble(mAmp * SCL_Amp, MIN_Amp * SCL_Amp, MAX_Amp * SCL_Amp) / SCL_Amp);
 
    mCanClip = mClip->GetValue();
 
@@ -322,11 +322,11 @@ void EffectAmplify::OnAmpText(wxCommandEvent & WXUNUSED(evt))
       return;
    }
 
-   mRatio = pow(10.0, TrapDouble(mAmp * SCL_Amp, MIN_Amp * SCL_Amp, MAX_Amp * SCL_Amp) / (20.0 * SCL_Amp));
+   mRatio = DB_TO_LINEAR(TrapDouble(mAmp * SCL_Amp, MIN_Amp * SCL_Amp, MAX_Amp * SCL_Amp) / SCL_Amp);
 
-   mAmpS->SetValue((int) (20.0 * log10(mRatio) * SCL_Amp + 0.5));
+   mAmpS->SetValue((int) (LINEAR_TO_DB(mRatio) * SCL_Amp + 0.5));
 
-   mNewPeak = 20.0 * log10(mRatio * mPeak);
+   mNewPeak = LINEAR_TO_DB(mRatio * mPeak);
    mNewPeakT->GetValidator()->TransferToWindow();
 
    CheckClip();
@@ -343,12 +343,12 @@ void EffectAmplify::OnPeakText(wxCommandEvent & WXUNUSED(evt))
    if (mNewPeak == 0.0)
       mRatio = mRatioClip;
    else
-      mRatio = pow(10.0, mNewPeak / 20.0) / mPeak;
+      mRatio = DB_TO_LINEAR(mNewPeak) / mPeak;
 
-   double ampInit = 20.0 * log10(mRatio);
+   double ampInit = LINEAR_TO_DB(mRatio);
    mAmp = TrapDouble(ampInit, MIN_Amp, MAX_Amp);
    if (mAmp != ampInit)
-      mRatio = pow(10.0, mAmp / 20.0);
+      mRatio = DB_TO_LINEAR(mAmp);
 
    mAmpT->GetValidator()->TransferToWindow();
 
@@ -360,20 +360,20 @@ void EffectAmplify::OnPeakText(wxCommandEvent & WXUNUSED(evt))
 void EffectAmplify::OnAmpSlider(wxCommandEvent & evt)
 {
    double dB = evt.GetInt() / SCL_Amp;
-   mRatio = pow(10.0, TrapDouble(dB, MIN_Amp, MAX_Amp) / 20.0);
+   mRatio = DB_TO_LINEAR(TrapDouble(dB, MIN_Amp, MAX_Amp));
 
    double dB2 = (evt.GetInt() - 1) / SCL_Amp;
-   double ratio2 = pow(10.0, TrapDouble(dB2, MIN_Amp, MAX_Amp) / 20.0);
+   double ratio2 = DB_TO_LINEAR(TrapDouble(dB2, MIN_Amp, MAX_Amp));
 
    if (!mClip->GetValue() && mRatio * mPeak > 1.0 && ratio2 * mPeak < 1.0)
    {
       mRatio = 1.0 / mPeak;
    }
 
-   mAmp = 20.0 * log10(mRatio);
+   mAmp = LINEAR_TO_DB(mRatio);
    mAmpT->GetValidator()->TransferToWindow();
 
-   mNewPeak = 20.0 * log10(mRatio * mPeak);
+   mNewPeak = LINEAR_TO_DB(mRatio * mPeak);
    mNewPeakT->GetValidator()->TransferToWindow();
 
    CheckClip();

src/effects/AutoDuck.cpp

@@ -278,7 +278,7 @@ bool EffectAutoDuck::Process()
    sampleCount minSamplesPause =
       mControlTrack->TimeToLongSamples(maxPause);
 
-   double threshold = pow(10.0, mThresholdDb/20);
+   double threshold = DB_TO_LINEAR(mThresholdDb);
 
    // adjust the threshold so we can compare it to the rmsSum value
    threshold = threshold * threshold * kRMSWindowSize;
@@ -553,7 +553,7 @@ bool EffectAutoDuck::ApplyDuckFade(int trackNumber, WaveTrack* t,
          if (gain < mDuckAmountDb)
             gain = mDuckAmountDb;
 
-         buf[i - pos] *= pow(10.0, gain / 20.0);
+         buf[i - pos] *= DB_TO_LINEAR(gain);
       }
 
       t->Set((samplePtr)buf, floatSample, pos, len);

src/effects/BassTreble.cpp

@@ -155,7 +155,7 @@ sampleCount EffectBassTreble::ProcessBlock(float **inBlock, float **outBlock, sa
    }
    else
    {
-      float gain = (pow(10.0, dB_level / 20.0f)) / mMax;
+      float gain = DB_TO_LINEAR(dB_level) / mMax;
       for (sampleCount i = 0; i < blockLen; i++)
       {
          // Normalize to specified level

src/effects/Compressor.cpp

@@ -328,8 +328,8 @@ bool EffectCompressor::TransferDataFromWindow()
 
 bool EffectCompressor::NewTrackPass1()
 {
-   mThreshold = pow(10.0, mThresholdDB/20); // factor of 20 because it's power
+   mThreshold = DB_TO_LINEAR(mThresholdDB);
-   mNoiseFloor = pow(10.0, mNoiseFloorDB/20);
+   mNoiseFloor = DB_TO_LINEAR(mNoiseFloorDB);
    mNoiseCounter = 100;
 
    mAttackInverseFactor = exp(log(mThreshold) / (mCurRate * mAttackTime + 0.5));

src/effects/Contrast.cpp

@@ -112,7 +112,7 @@ float ContrastDialog::GetDB()
    {
       if( rms < 1.0E-30 )
          return -60.0;
-      return 20.0*log10(rms);
+      return LINEAR_TO_DB(rms);
    }
    else
    {

src/effects/Equalization.cpp

@@ -1182,13 +1182,13 @@ bool EffectEqualization::CalcFilter()
    }
    mFilterFuncR[mWindowSize/2] = val1;
 
-   mFilterFuncR[0] = (float)(pow(10., mFilterFuncR[0]/20.));
+   mFilterFuncR[0] = DB_TO_LINEAR(mFilterFuncR[0]);
    for(i=1;i<mWindowSize/2;i++)
    {
-      mFilterFuncR[i] = (float)(pow(10., mFilterFuncR[i]/20.));
+      mFilterFuncR[i] = DB_TO_LINEAR(mFilterFuncR[i]);
       mFilterFuncR[mWindowSize-i]=mFilterFuncR[i];   //Fill entire array
    }
-   mFilterFuncR[i] = (float)(pow(10., mFilterFuncR[i]/20.));   //do last one
+   mFilterFuncR[i] = DB_TO_LINEAR(mFilterFuncR[i]);   //do last one
 
    //transfer to time domain to do the padding and windowing
    float *outr = new float[mWindowSize];
@@ -2773,7 +2773,7 @@ void EqualizationPanel::OnPaint(wxPaintEvent &  WXUNUSED(event))
          yF += mOutr[halfM];
          yF = fabs(yF);
          if(yF!=0.)
-            yF = 20.0*log10(yF);   //20 here as an amplitude
+            yF = LINEAR_TO_DB(yF);
          else
             yF = mEffect->mdBMin;
       }

src/effects/NoiseReduction.cpp

@@ -765,10 +765,10 @@ EffectNoiseReduction::Worker::Worker
    const int nAttackBlocks = 1 + (int)(settings.mAttackTime * sampleRate / mStepSize);
    const int nReleaseBlocks = 1 + (int)(settings.mReleaseTime * sampleRate / mStepSize);
    // Applies to amplitudes, divide by 20:
-   mNoiseAttenFactor = pow(10.0, noiseGain / 20.0);
+   mNoiseAttenFactor = DB_TO_LINEAR(noiseGain);
    // Apply to gain factors which apply to amplitudes, divide by 20:
-   mOneBlockAttack = pow(10.0, (noiseGain / (20.0 * nAttackBlocks)));
+   mOneBlockAttack = DB_TO_LINEAR(noiseGain / nAttackBlocks);
-   mOneBlockRelease = pow(10.0, (noiseGain / (20.0 * nReleaseBlocks)));
+   mOneBlockRelease = DB_TO_LINEAR(noiseGain / nReleaseBlocks);
    // Applies to power, divide by 10:
    mOldSensitivityFactor = pow(10.0, settings.mOldSensitivity / 10.0);
 

src/effects/NoiseRemoval.cpp

@@ -275,10 +275,8 @@ void EffectNoiseRemoval::Initialize()
    mFreqSmoothingBins = (int)(mFreqSmoothingHz * mWindowSize / mSampleRate);
    mAttackDecayBlocks = 1 +
       (int)(mAttackDecayTime * mSampleRate / (mWindowSize / 2));
-   // Applies to amplitudes, divide by 20:
+   mNoiseAttenFactor = DB_TO_LINEAR(mNoiseGain);
-   mNoiseAttenFactor = pow(10.0, mNoiseGain/20.0);
+   mOneBlockAttackDecay = DB_TO_LINEAR(mNoiseGain / mAttackDecayBlocks);
-   // Applies to gain factors which apply to amplitudes, divide by 20:
-   mOneBlockAttackDecay = pow(10.0, (mNoiseGain / (20.0 * mAttackDecayBlocks)));
    // Applies to power, divide by 10:
    mSensitivityFactor = pow(10.0, mSensitivity/10.0);
    mMinSignalBlocks =

src/effects/Normalize.cpp

@@ -152,9 +152,8 @@ bool EffectNormalize::Process()
 
    float ratio;
    if( mGain )
-      ratio = pow(10.0,TrapDouble(mLevel, // same value used for all tracks
+      // same value used for all tracks
-                               MIN_Level,
+      ratio = DB_TO_LINEAR(TrapDouble(mLevel, MIN_Level, MAX_Level));
-                               MAX_Level)/20.0);
    else
       ratio = 1.0;
 

src/effects/ScienFilter.cpp

@@ -725,7 +725,7 @@ bool EffectScienFilter::CalcFilter()
       }
       if ((mOrder & 1) == 0)
       {
-         float fTemp = pow (10.0, -wxMax(0.001, mRipple) / 20.0);      // at DC the response is down R dB (for even-order)
+         float fTemp = DB_TO_LINEAR(-wxMax(0.001, mRipple));      // at DC the response is down R dB (for even-order)
          mpBiquad[0].fNumerCoeffs [0] *= fTemp;
          mpBiquad[0].fNumerCoeffs [1] *= fTemp;
          mpBiquad[0].fNumerCoeffs [2] *= fTemp;
@@ -761,7 +761,7 @@ bool EffectScienFilter::CalcFilter()
    case kChebyshevTypeII:     // Chebyshev Type 2
       float fSZeroX, fSZeroY;
       float fSPoleX, fSPoleY;
-      eps = pow (10.0, -wxMax(0.001, mStopbandRipple) / 20.0);
+      eps = DB_TO_LINEAR(-wxMax(0.001, mStopbandRipple));
       a = log (1 / eps + sqrt(1 / square(eps) + 1)) / mOrder;
 
       // Assume even order
@@ -1131,7 +1131,7 @@ void EffectScienFilterPanel::OnPaint(wxPaintEvent & WXUNUSED(evt))
       x = mEnvRect.x + i;
       freq = pow(10.0, loLog + i * step);          //Hz
       yF = mEffect->FilterMagnAtFreq (freq);
-      yF = 20.0 * log10(yF);
+      yF = LINEAR_TO_DB(yF);
 
       if (yF < mDbMin)
       {

src/widgets/ASlider.cpp

@@ -292,7 +292,7 @@ bool SliderDialog::TransferDataFromWindow()
 
    mTextCtrl->GetValue().ToDouble(&value);
    if (mStyle == DB_SLIDER)
-      value = pow(10.0, value / 20.0);
+      value = DB_TO_LINEAR(value);
    mSlider->Set(value);
 
    return true;
@@ -1330,7 +1330,7 @@ float LWSlider::DragPositionToValue(int fromPos, bool shiftDown)
 float LWSlider::Get( bool convert )
 {
    if (mStyle == DB_SLIDER)
-      return ( convert ? pow(10.0f, mCurrentValue / 20.0f) : mCurrentValue );
+      return (convert ? DB_TO_LINEAR(mCurrentValue) : mCurrentValue);
    else
       return mCurrentValue;
 }
@@ -1340,7 +1340,7 @@ void LWSlider::Set(float value)
    if (mIsDragging)
       return;
    if (mStyle == DB_SLIDER)
-      mCurrentValue = 20.0f*log10(value);
+      mCurrentValue = LINEAR_TO_DB(value);
    else
       mCurrentValue = value;
 

src/widgets/Meter.cpp

@@ -864,7 +864,7 @@ static float ToDB(float v, float range)
 {
    double db;
    if (v > 0)
-      db = 20 * log10(fabs(v));
+      db = LINEAR_TO_DB(fabs(v));
    else
       db = -999;
    return ClipZeroToOne((db + range) / range);
@@ -995,7 +995,7 @@ void Meter::OnMeterUpdate(wxTimerEvent & WXUNUSED(event))
             }
             else {
                double decayAmount = mDecayRate * deltaT;
-               double decayFactor = pow(10.0, -decayAmount/20);
+               double decayFactor = DB_TO_LINEAR(-decayAmount);
                mBar[j].peak = floatMax(msg.peak[j],
                                        mBar[j].peak * decayFactor);
             }