Fix for bug #927

At least I'm pretty sure this addresses all of the example Peter
mentions.

src/effects/Amplify.cpp

@@ -66,6 +66,7 @@ EffectAmplify::EffectAmplify()
    mRatio = powf(10.0f, mAmp / 20.0f);
    mCanClip = false;
    mPeak = 0.0f;
+   mTracksAnalyzed = false;
 }
 
 EffectAmplify::~EffectAmplify()
@@ -134,6 +135,8 @@ bool EffectAmplify::SetAutomationParameters(EffectAutomationParameters & parms)
 
 bool EffectAmplify::Init()
 {
+   if (!mTracksAnalyzed)
+   {
       mPeak = 0.0f;
 
       SelectedTrackListOfKindIterator iter(Track::Wave, mTracks);
@@ -150,6 +153,9 @@ bool EffectAmplify::Init()
          }
       }
 
+      mTracksAnalyzed = true;
+   }
+
    return true;
 }
 

src/effects/Amplify.h

@@ -68,6 +68,7 @@ private:
 
 private:
    float mPeak;
+   bool mTracksAnalyzed;
 
    float mRatio;
    float mAmp;