diff --git a/lib-src/sbsms/include/sbsms.h b/lib-src/sbsms/include/sbsms.h
index 167c9e4be..5cd94a805 100644
--- a/lib-src/sbsms/include/sbsms.h
+++ b/lib-src/sbsms/include/sbsms.h
@@ -51,6 +51,7 @@ class SBSMSInterface {
   virtual ~SBSMSInterface() {}
   virtual long samples(audio *buf, long n) { return 0; }
   virtual float getStretch(float t)=0;
+  virtual float getMeanStretch(float t0, float t1)=0;
   virtual float getPitch(float t)=0;
   virtual long getPresamples()=0;
   virtual SampleCountType getSamplesToInput()=0;
@@ -127,8 +128,10 @@ class Slide {
   ~Slide();
   float getTotalStretch();
   float getStretchedTime(float t);
+  float getInverseStretchedTime(float t);
   float getRate(float t);
   float getStretch(float t);
+  float getMeanStretch(float t0, float t1);
   float getRate();
   float getStretch();
   void step();
@@ -148,6 +151,7 @@ public:
                         SBSMSQuality *quality);
   virtual ~SBSMSInterfaceSliding();
   virtual float getStretch(float t);
+  virtual float getMeanStretch(float t0, float t1);
   virtual float getPitch(float t);
   virtual long getPresamples();
   virtual SampleCountType getSamplesToInput();
diff --git a/lib-src/sbsms/src/sbsms.cpp b/lib-src/sbsms/src/sbsms.cpp
index 6a8cf0632..111747b4a 100644
--- a/lib-src/sbsms/src/sbsms.cpp
+++ b/lib-src/sbsms/src/sbsms.cpp
@@ -663,7 +663,8 @@ long SBSMSImp :: write(SBSMSInterface *iface)
   long nWrite = 0;
 
   float t = getInputTime(iface);
-  float stretch = iface->getStretch(t);
+  float t1 = (float)(nSamplesInputed + quality->getFrameSize()) / (float)iface->getSamplesToInput();
+  float stretch = iface->getMeanStretch(t,t1);
   float pitch = iface->getPitch(t);
 
   long nPresamples = iface->getPresamples();
diff --git a/lib-src/sbsms/src/slide.cpp b/lib-src/sbsms/src/slide.cpp
index ce11b18f9..7f5059a06 100644
--- a/lib-src/sbsms/src/slide.cpp
+++ b/lib-src/sbsms/src/slide.cpp
@@ -11,8 +11,10 @@ public:
   virtual ~SlideImp() {}
   virtual float getTotalStretch()=0;
   virtual float getStretchedTime(float t)=0;
+  virtual float getInverseStretchedTime(float t)=0;
   virtual float getRate(float t)=0;
   virtual float getStretch(float t)=0;
+  virtual float getMeanStretch(float t0, float t1)=0;
   virtual float getRate()=0;
   virtual float getStretch()=0;
   virtual void step()=0;
@@ -28,12 +30,18 @@ public:
   float getStretchedTime(float t) {
     return t;
   }
+  float getInverseStretchedTime(float t) {
+    return t;
+  }
   float getRate(float t) {
     return 1.0f;
   }
   float getStretch(float t) {
     return 1.0f;
   }
+  float getMeanStretch(float t0, float t1) {
+    return 1.0f;
+  }
   float getRate() {
     return 1.0f;
   }
@@ -55,12 +63,18 @@ public:
   float getStretchedTime(float t) {
     return t / rate;
   }
+  float getInverseStretchedTime(float t) {
+    return rate * t;
+  }
   float getRate(float t) {
     return rate;
   }
   float getStretch(float t) {
     return 1.0f / rate;
   }
+  float getMeanStretch(float t0, float t1) {
+    return 1.0f / rate;
+  }
   float getRate() {
     return rate;
   }
@@ -90,12 +104,18 @@ public:
     float ratet = getRate(t);
     return log(ratet / rate0) / (rate1 - rate0);
   }
+  float getInverseStretchedTime(float t) {
+    return (exp((rate1-rate0)*t)-1.0f)*rate0/(rate1-rate0);
+  }
   float getRate(float t) {
     return rate0 + (rate1 - rate0) * t;
   }
   float getStretch(float t) {
     return 1.0f / getRate(t);
   }
+  float getMeanStretch(float t0, float t1) {
+    return log(getRate(t1)/getRate(t0))/((rate1-rate0)*(t1-t0));
+  }
   float getRate() {
     return (float)val;
   }
@@ -126,12 +146,22 @@ public:
   float getStretchedTime(float t) {
     return (sqrt(rate0 * rate0 + (rate1 * rate1 - rate0 * rate0) * t) - rate0) * 2.0f / (rate1 * rate1 - rate0 * rate0);
   }
+  float getInverseStretchedTime(float t) {
+    float r12 = rate1 * rate1 - rate0 * rate0;
+    float s = 0.5f * r12 * t + rate0;
+    return (s * s - rate0 * rate0) / r12;
+  }
   float getRate(float t) {
-    return rate0 + (sqrt(rate0 * rate0 + (rate1 * rate1 - rate0 * rate0) * t) - rate0);
+    return sqrt(rate0 * rate0 + (rate1 * rate1 - rate0 * rate0) * t);
   }
   float getStretch(float t) {
     return 1.0f / getRate(t);
   }
+  float getMeanStretch(float t0, float t1) {
+    float r02 = rate0 * rate0;
+    float r102 = rate1 * rate1 - r02;
+    return 2.0f * (sqrt(r02 + r102*t1) - sqrt(r02 + r102 * t0)) / (r102 * (t1 - t0));
+  }
   float getRate() {
     return getRate((float)val);
   }
@@ -162,12 +192,19 @@ public:
   float getStretchedTime(float t) {
     return t / rate0 * (1.0f + 0.5f * t * (rate0 / rate1 - 1.0f));
   }
+  float getInverseStretchedTime(float t) {
+    float s = 1.0f / rate1 - 1.0f / rate0;
+    return (-1.0f / rate0 + sqrt(1/(rate0*rate0)-2.0f*t*s)) / s;
+  }
   float getRate(float t) {
     return 1.0f / getStretch(t);
   }
   float getStretch(float t) {
     return (1.0f / rate0 + (1.0f / rate1 - 1.0f / rate0) * t);
   }
+  float getMeanStretch(float t0, float t1) {
+    return ((t1 + t0) * (rate0 - rate1)  - 2.0f * rate1) / (2.0f * rate0 * rate1);
+  }
   float getRate() {
     return (float)(1.0 / val);
   }
@@ -200,12 +237,18 @@ public:
   float getStretchedTime(float t) {
     return c1 * (pow(c0, t) - 1.0f);
   }
+  float getInverseStretchedTime(float t) {
+    return log(t/c1 + 1.0f) * c1 * rate0;
+  }
   float getRate(float t) {
     return rate0 * pow(c0, -t);
   }
   float getStretch(float t) {
     return pow(c0, t) / rate0;
   }
+  float getMeanStretch(float t0, float t1) {
+    return (pow(c0,t1) - pow(c0,t0)) / (c1 * (t1 - t0));
+  }
   float getRate() {
     return getRate((float)val);
   }
@@ -226,16 +269,21 @@ public:
   GeometricInputSlide(float rate0, float rate1, const SampleCountType &n) {
     this->rate0 = rate0;
     this->rate1 = rate1;
+    this->c0 = rate0 / rate1;
+    this->log01 = log(c0);
     if(n) {
       val = rate0;
       inc = pow((double)rate1 / rate0, 1.0 / (double)n);
     }
   }
   float getTotalStretch() {
-    return (rate1 - rate0) / (log(rate1 / rate0) * (rate0 * rate1));
+    return (rate0 - rate1) / (log01 * (rate0 * rate1));
   }
   float getStretchedTime(float t) {
-    return (float)(pow(rate0 / rate1, t) - 1.0) / (rate0 * log(rate0 / rate1));
+    return (float)(pow(rate0 / rate1, t) - 1.0) / (rate0 * log01);
+  }
+  float getInverseStretchedTime(float t) {
+    return log(t * rate0 * log01 + 1.0f) / log01;
   }
   float getRate(float t) {
     return rate0 * pow(rate1 / rate0, t);
@@ -243,6 +291,9 @@ public:
   float getStretch(float t) {
     return 1.0f / getRate(t);
   }
+  float getMeanStretch(float t0, float t1) {
+    return (pow(c0,t1) - pow(c0,t0)) / (rate0 * log01 * (t1 - t0));
+  }
   float getRate() {
     return (float)val;
   }
@@ -253,7 +304,7 @@ public:
     val *= inc;
   }
 protected:
-  float rate0, rate1;
+  float rate0, rate1, c0, log01;
   double val, inc;
 };
 
@@ -276,6 +327,9 @@ public:
   float getStretchedTime(float t) {
     return log(r10 / rate0 * t + 1.0f) / r10;
   }
+  float getInverseStretchedTime(float t) {
+    return rate0 / r10 * (exp(t * r10) - 1.0f);
+  }
   float getRate(float t) {
     float t1 = getStretchedTime(t) / totalStretch;
     return rate0 * pow(rate1 / rate0, t1);
@@ -283,6 +337,9 @@ public:
   float getStretch(float t) {
     return 1.0f / getRate(t);
   }
+  float getMeanStretch(float t0, float t1) {
+    return log((rate0 + r10 * t1)/(rate0 + r10 * t0)) /(r10 * (t1 - t0));
+  }
   float getRate() {
     return getRate((float)val);
   }
@@ -347,6 +404,16 @@ float Slide :: getStretchedTime(float t)
   if(t > 1.0f) t = 1.0f;
   return imp->getStretchedTime(t);
 }
+  
+float Slide :: getMeanStretch(float t0, float t1) {
+  if(t0 < 0.0f) t0 = 0.0f;
+  return imp->getMeanStretch(t0,t1);
+}
+  
+float Slide :: getInverseStretchedTime(float t)
+{
+  return imp->getInverseStretchedTime(t);
+}
 
 float Slide :: getRate()
 {
@@ -374,6 +441,7 @@ public:
                            SBSMSQuality *quality);
   ~SBSMSInterfaceSlidingImp() {}
   inline float getStretch(float t);
+  inline float getMeanStretch(float t0, float t1);
   inline float getPitch(float t);
   inline long getPresamples();
   SampleCountType getSamplesToInput();
@@ -388,8 +456,7 @@ protected:
   SampleCountType samplesToInput;
   SampleCountType samplesToOutput;
 };
-
-
+  
 SBSMSInterfaceSlidingImp :: SBSMSInterfaceSlidingImp(Slide *stretchSlide,
                                                      Slide *pitchSlide, 
                                                      bool bPitchReferenceInput,
@@ -414,7 +481,8 @@ SBSMSInterfaceSlidingImp :: SBSMSInterfaceSlidingImp(Slide *stretchSlide,
     int inFrameSize = quality->getFrameSize();
     while(samplesIn < samplesToInput) {
       float t = (float)samplesIn / (float)samplesToInput;
-      stretch = stretchSlide->getStretch(t);
+      float t1 =(float)(samplesIn + inFrameSize) / (float)samplesToInput;
+      stretch = stretchSlide->getMeanStretch(t,t1);
       outFrameSizefloat += stretch * inFrameSize;
       int outFrameSize = (int) outFrameSizefloat;
       outFrameSizefloat -= (float) outFrameSize;
@@ -432,6 +500,12 @@ float SBSMSInterfaceSlidingImp :: getStretch(float t)
   return stretchScale * stretchSlide->getStretch(t);
 }
 
+float SBSMSInterfaceSliding :: getMeanStretch(float t0, float t1) { return imp->getMeanStretch(t0, t1); }
+float SBSMSInterfaceSlidingImp :: getMeanStretch(float t0, float t1)
+{
+  return stretchSlide->getMeanStretch(t0, t1);
+}
+  
 float SBSMSInterfaceSliding :: getPitch(float t) { return imp->getPitch(t); }
 float SBSMSInterfaceSlidingImp :: getPitch(float t)
 {
diff --git a/m4/audacity_checklib_libsbsms.m4 b/m4/audacity_checklib_libsbsms.m4
index f4210a6d1..c2f80dddd 100644
--- a/m4/audacity_checklib_libsbsms.m4
+++ b/m4/audacity_checklib_libsbsms.m4
@@ -12,7 +12,7 @@ AC_DEFUN([AUDACITY_CHECKLIB_LIBSBSMS], [
 
    dnl see if sbsms is installed on the system
 
-   PKG_CHECK_MODULES(SBSMS, sbsms >= 1.6.0,
+   PKG_CHECK_MODULES(SBSMS, sbsms >= 2.2.0,
                      LIBSBSMS_SYSTEM_AVAILABLE="yes",
                      LIBSBSMS_SYSTEM_AVAILABLE="no")
 
diff --git a/src/effects/SBSMSEffect.cpp b/src/effects/SBSMSEffect.cpp
index 3cbed773b..6eea600ae 100644
--- a/src/effects/SBSMSEffect.cpp
+++ b/src/effects/SBSMSEffect.cpp
@@ -200,6 +200,18 @@ bool EffectSBSMS::ProcessLabelTrack(Track *t)
    return true;
 }
 
+double EffectSBSMS::getInvertedStretchedTime(double rateStart, double rateEnd, SlideType slideType, double outputTime)
+{
+   Slide slide(slideType,rateStart,rateEnd,0);
+   return slide.getInverseStretchedTime(outputTime);
+}
+
+double EffectSBSMS::getRate(double rateStart, double rateEnd, SlideType slideType, double t)
+{
+   Slide slide(slideType,rateStart,rateEnd,0);
+   return slide.getRate(t);
+}
+
 bool EffectSBSMS::Process()
 {
    bool bGoodResult = true;
@@ -307,6 +319,8 @@ bool EffectSBSMS::Process()
                                                        bPitchReferenceInput,
                                                        samplesToProcess,0,
                                                        NULL);
+               
+             
             } else {
               rb.bPitch = false;
               outSlideType = (srProcess==srTrack?SlideIdentity:SlideConstant);
@@ -330,7 +344,7 @@ bool EffectSBSMS::Process()
                                                       samplesToProcess,processPresamples,
                                                       rb.quality);
             }
-
+            
             Resampler resampler(outResampleCB,&rb,outSlideType);
 
             audio outBuf[SBSMSOutBlockSize];
diff --git a/src/effects/SBSMSEffect.h b/src/effects/SBSMSEffect.h
index 205ece823..14ba2e17c 100644
--- a/src/effects/SBSMSEffect.h
+++ b/src/effects/SBSMSEffect.h
@@ -28,7 +28,8 @@ public:
    void setParameters(double rateStart, double rateEnd, double pitchStart, double pitchEnd,
                       SlideType rateSlideType, SlideType pitchSlideType,
                       bool bLinkRatePitch, bool bRateReferenceInput, bool bPitchReferenceInput);
-
+   static double getInvertedStretchedTime(double rateStart, double rateEnd, SlideType slideType, double outputTime);
+   static double getRate(double rateStart, double rateEnd, SlideType slideType, double t);
 private:
    bool ProcessLabelTrack(Track *track);
    double rateStart, rateEnd, pitchStart, pitchEnd;
diff --git a/src/effects/TimeScale.cpp b/src/effects/TimeScale.cpp
index 103474cb8..225493174 100644
--- a/src/effects/TimeScale.cpp
+++ b/src/effects/TimeScale.cpp
@@ -72,6 +72,11 @@ EffectTimeScale::EffectTimeScale()
    m_PitchPercentChangeStart = DEF_PitchPercentStart;
    m_PitchPercentChangeEnd = DEF_PitchPercentEnd;
 
+   slideTypeRate = SlideLinearOutputRate;
+   slideTypePitch = SlideLinearOutputRate;
+   bPreview = false;
+   previewSelectedDuration = 0.0;
+   
    SetLinearEffectFlag(true);
 }
 
@@ -143,13 +148,42 @@ bool EffectTimeScale::Init()
    return true;
 }
 
+double EffectTimeScale::CalcPreviewInputLength(double previewLength)
+{
+   double inputLength = Effect::GetDuration();
+   if(inputLength == 0.0) {
+      return 0.0;
+   } else {
+      double rateStart = PercentChangeToRatio(m_RatePercentChangeStart);
+      double rateEnd = PercentChangeToRatio(m_RatePercentChangeEnd);
+      double tOut = previewLength/inputLength;
+      double t = EffectSBSMS::getInvertedStretchedTime(rateStart,rateEnd,slideTypeRate,tOut);
+      return t * inputLength;
+   }
+}
+
+void EffectTimeScale::Preview(bool dryOnly)
+{
+   previewSelectedDuration = Effect::GetDuration();
+   bPreview = true;
+   Effect::Preview(dryOnly);
+   bPreview = false;
+}
+
 bool EffectTimeScale::Process()
 {
    double pitchStart = PercentChangeToRatio(m_PitchPercentChangeStart);
    double pitchEnd = PercentChangeToRatio(m_PitchPercentChangeEnd);
    double rateStart = PercentChangeToRatio(m_RatePercentChangeStart);
    double rateEnd = PercentChangeToRatio(m_RatePercentChangeEnd);
-   EffectSBSMS::setParameters(rateStart,rateEnd,pitchStart,pitchEnd,SlideLinearOutputRate,SlideLinearOutputRate,false,false,false);
+  
+   if(bPreview) {
+      double t = (mT1-mT0) / previewSelectedDuration;
+      rateEnd = EffectSBSMS::getRate(rateStart,rateEnd,slideTypeRate,t);
+      pitchEnd = EffectSBSMS::getRate(pitchStart,pitchEnd,slideTypePitch,t);
+   }
+   
+   EffectSBSMS::setParameters(rateStart,rateEnd,pitchStart,pitchEnd,slideTypeRate,slideTypePitch,false,false,false);
    return EffectSBSMS::Process();
 }
 
diff --git a/src/effects/TimeScale.h b/src/effects/TimeScale.h
index f684a50d8..fe7852a40 100644
--- a/src/effects/TimeScale.h
+++ b/src/effects/TimeScale.h
@@ -50,10 +50,12 @@ public:
    // Effect implementation
 
    virtual bool Init();
+   virtual void Preview(bool dryOnly);
    virtual bool Process();
    virtual void PopulateOrExchange(ShuttleGui & S);
    virtual bool TransferDataToWindow();
    virtual bool TransferDataFromWindow();
+   virtual double CalcPreviewInputLength(double previewLength);
 
 private:
    // EffectTimeScale implementation
@@ -82,6 +84,10 @@ private:
    void Update_Slider_RatePercentChangeEnd();
 
 private:
+   bool bPreview;
+   double previewSelectedDuration;
+   SlideType slideTypeRate;
+   SlideType slideTypePitch;
    double m_RatePercentChangeStart;
    double m_RatePercentChangeEnd;
    double m_PitchHalfStepsStart;