Fix stereo to mono

src/effects/StereoToMono.cpp

@@ -17,6 +17,8 @@
 
 #include <wx/intl.h>
 
+#include "../Project.h"
+
 #include "StereoToMono.h"
 
 EffectStereoToMono::EffectStereoToMono()
@@ -64,21 +66,116 @@ int EffectStereoToMono::GetAudioOutCount()
    return 1;
 }
 
-sampleCount EffectStereoToMono::ProcessBlock(float **inBlock, float **outBlock, sampleCount blockLen)
-{
-   float *left = inBlock[0];
-   float *right = inBlock[1];
-   float *mono = outBlock[0];
+// Effect implementatino
 
-   for (sampleCount i = 0; i < blockLen; i++)
+bool EffectStereoToMono::Process()
+{
+   // Do not use mWaveTracks here.  We will possibly delete tracks,
+   // so we must use the "real" tracklist.
+   this->CopyInputTracks(); // Set up mOutputTracks.
+   bool bGoodResult = true;
+
+   SelectedTrackListOfKindIterator iter(Track::Wave, mOutputTracks);
+   mLeftTrack = (WaveTrack *)iter.First();
+   bool refreshIter = false;
+
+   if(mLeftTrack)
    {
-      mono[i] = (left[i] + right[i]) / 2.0;
+      // create a new WaveTrack to hold all of the output
+      AudacityProject *p = GetActiveProject();
+      mOutTrack = p->GetTrackFactory()->NewWaveTrack(floatSample, mLeftTrack->GetRate());
    }
 
-   return blockLen;
+   int count = 0;
+   while (mLeftTrack) {
+      if (mLeftTrack->GetKind() == Track::Wave &&
+         mLeftTrack->GetSelected() &&
+         mLeftTrack->GetLinked()) {
+
+         mRightTrack = (WaveTrack *)iter.Next();
+
+         if ((mLeftTrack->GetRate() == mRightTrack->GetRate())) {
+            sampleCount leftTrackStart = mLeftTrack->TimeToLongSamples(mLeftTrack->GetStartTime());
+            sampleCount rightTrackStart = mRightTrack->TimeToLongSamples(mRightTrack->GetStartTime());
+            mStart = wxMin(leftTrackStart, rightTrackStart);
+
+            sampleCount leftTrackEnd = mLeftTrack->TimeToLongSamples(mLeftTrack->GetEndTime());
+            sampleCount rightTrackEnd = mRightTrack->TimeToLongSamples(mRightTrack->GetEndTime());
+            mEnd = wxMax(leftTrackEnd, rightTrackEnd);
+
+            bGoodResult = ProcessOne(count);
+            if (!bGoodResult)
+               break;
+
+            mOutTrack->Clear(mOutTrack->GetStartTime(), mOutTrack->GetEndTime());
+
+            // The right channel has been deleted, so we must restart from the beginning
+            refreshIter = true;
+         }
+      }
+
+      if (refreshIter) {
+         mLeftTrack = (WaveTrack *)iter.First();
+         refreshIter = false;
+      }
+      else {
+         mLeftTrack = (WaveTrack *)iter.Next();
+      }
+      count++;
+   }
+
+   if(mOutTrack)
+      delete mOutTrack;
+   this->ReplaceProcessedTracks(bGoodResult);
+   return bGoodResult;
 }
 
-// Effect implementatino
+bool EffectStereoToMono::ProcessOne(int count)
+{
+   float  curLeftFrame;
+   float  curRightFrame;
+   float  curMonoFrame;
+
+   sampleCount idealBlockLen = mLeftTrack->GetMaxBlockSize() * 2;
+   sampleCount index = mStart;
+   float *leftBuffer = new float[idealBlockLen];
+   float *rightBuffer = new float[idealBlockLen];
+   bool bResult = true;
+
+   while (index < mEnd) {
+      bResult &= mLeftTrack->Get((samplePtr)leftBuffer, floatSample, index, idealBlockLen);
+      bResult &= mRightTrack->Get((samplePtr)rightBuffer, floatSample, index, idealBlockLen);
+      sampleCount limit = idealBlockLen;
+      if ((index + idealBlockLen) > mEnd) {
+         limit = mEnd - index;
+      }
+      for (sampleCount i = 0; i < limit; ++i) {
+         index++;
+         curLeftFrame = leftBuffer[i];
+         curRightFrame = rightBuffer[i];
+         curMonoFrame = (curLeftFrame + curRightFrame) / 2.0;
+         leftBuffer[i] = curMonoFrame;
+      }
+      bResult &= mOutTrack->Append((samplePtr)leftBuffer, floatSample, limit);
+      if (TrackProgress(count, 2.*((double)index / (double)(mEnd - mStart))))
+         return false;
+   }
+
+   double minStart = wxMin(mLeftTrack->GetStartTime(), mRightTrack->GetStartTime());
+   bResult &= mLeftTrack->Clear(mLeftTrack->GetStartTime(), mLeftTrack->GetEndTime());
+   bResult &= mOutTrack->Flush();
+   bResult &= mLeftTrack->Paste(minStart, mOutTrack);
+   mLeftTrack->SetLinked(false);
+   mRightTrack->SetLinked(false);
+   mLeftTrack->SetChannel(Track::MonoChannel);
+   mOutputTracks->Remove(mRightTrack);
+   delete mRightTrack;
+
+   delete [] leftBuffer;
+   delete [] rightBuffer;
+
+   return bResult;
+}
 
 bool EffectStereoToMono::IsHidden()
 {

src/effects/StereoToMono.h

@@ -37,11 +37,23 @@ public:
 
    virtual int GetAudioInCount();
    virtual int GetAudioOutCount();
-   virtual sampleCount ProcessBlock(float **inBlock, float **outBlock, sampleCount blockLen);
 
    // Effect implementation
 
-   bool IsHidden();
+   virtual bool Process();
+   virtual bool IsHidden();
+
+private:
+   // EffectStereoToMono implementation
+
+   bool ProcessOne(int count);
+
+private:
+   sampleCount mStart;
+   sampleCount mEnd;
+   WaveTrack *mLeftTrack;
+   WaveTrack *mRightTrack;
+   WaveTrack *mOutTrack;
 };
 
 #endif