diff --git a/src/engine/engine.h b/src/engine/engine.h
index 25add2069..f94cb3e1f 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -197,6 +197,10 @@ struct DivDispatchContainer {
   bool lowQuality, dcOffCompensation;
   double rateMemory;
 
+  // used in multi-thread
+  int cycles;
+  unsigned int size;
+
   void setRates(double gotRate);
   void setQuality(bool lowQual);
   void grow(size_t size);
@@ -215,7 +219,9 @@ struct DivDispatchContainer {
     lastAvail(0),
     lowQuality(false),
     dcOffCompensation(false),
-    rateMemory(0.0) {
+    rateMemory(0.0),
+    cycles(0),
+    size(0) {
     memset(bb,0,DIV_MAX_OUTPUTS*sizeof(blip_buffer_t*));
     memset(temp,0,DIV_MAX_OUTPUTS*sizeof(int));
     memset(prevSample,0,DIV_MAX_OUTPUTS*sizeof(int));
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 5f06d31aa..1cb7b62d8 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1760,6 +1760,13 @@ void DivEngine::runMidiTime(int totalCycles) {
   }
 }
 
+void _runDispatch1(void* d) {
+}
+
+void _runDispatch2(void* d) {
+
+}
+
 void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsigned int size) {
   lastNBIns=inChans;
   lastNBOuts=outChans;
@@ -2066,9 +2073,11 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
         // 5. tick the clock and fill buffers as needed
         if (cycles<runLeftG) {
           for (int i=0; i<song.systemLen; i++) {
-            renderPool->push([this,size](void* d) {
+            disCont[i].cycles=cycles;
+            disCont[i].size=size;
+            renderPool->push([](void* d) {
               DivDispatchContainer* dc=(DivDispatchContainer*)d;
-              int total=(cycles*dc->runtotal)/(size<<MASTER_CLOCK_PREC);
+              int total=(dc->cycles*dc->runtotal)/(dc->size<<MASTER_CLOCK_PREC);
               dc->acquire(dc->runPos,total);
               dc->runLeft-=total;
               dc->runPos+=total;
diff --git a/src/engine/workPool.cpp b/src/engine/workPool.cpp
index 643e56f0c..fd1993aa1 100644
--- a/src/engine/workPool.cpp
+++ b/src/engine/workPool.cpp
@@ -71,7 +71,7 @@ void DivWorkThread::run() {
   }
 }
 
-bool DivWorkThread::assign(const std::function<void(void*)>& what, void* arg) {
+bool DivWorkThread::assign(void (*what)(void*), void* arg) {
   lock.lock();
   if (tasks.size()>=30) {
     lock.unlock();
@@ -105,7 +105,7 @@ void DivWorkThread::init(DivWorkPool* p) {
   thread=new std::thread(_workThread,this);
 }
 
-void DivWorkPool::push(const std::function<void(void*)>& what, void* arg) {
+void DivWorkPool::push(void (*what)(void*), void* arg) {
   // if no work threads, just execute
   if (!threaded) {
     what(arg);
diff --git a/src/engine/workPool.h b/src/engine/workPool.h
index ef430f1ce..7b16d3339 100644
--- a/src/engine/workPool.h
+++ b/src/engine/workPool.h
@@ -31,9 +31,9 @@
 class DivWorkPool;
 
 struct DivPendingTask {
-  std::function<void(void*)> func;
+  void (*func)(void*);
   void* funcArg;
-  DivPendingTask(std::function<void(void*)> f, void* arg):
+  DivPendingTask(void (*f)(void*), void* arg):
     func(f),
     funcArg(arg) {}
   DivPendingTask():
@@ -52,7 +52,7 @@ struct DivWorkThread {
   bool promiseAlreadySet;
 
   void run();
-  bool assign(const std::function<void(void*)>& what, void* arg);
+  bool assign(void (*what)(void*), void* arg);
   void wait();
   bool busy();
   void finish();
@@ -82,7 +82,7 @@ class DivWorkPool {
      * push a new job to this work pool.
      * if all work threads are busy, this will block until one is free.
      */
-    void push(const std::function<void(void*)>& what, void* arg);
+    void push(void (*what)(void*), void* arg);
     
     /**
      * check whether this work pool is busy.
diff --git a/src/gui/chanOsc.cpp b/src/gui/chanOsc.cpp
index 3496fe895..04908702e 100644
--- a/src/gui/chanOsc.cpp
+++ b/src/gui/chanOsc.cpp
@@ -60,7 +60,7 @@ float FurnaceGUI::computeGradPos(int type, int chan) {
       return 1.0f;
       break;
     case GUI_OSCREF_FREQUENCY:
-      return chanOscPitch[chan];
+      return chanOscChan[chan].pitch;
       break;
     case GUI_OSCREF_VOLUME:
       return chanOscVol[chan];
@@ -416,10 +416,11 @@ void FurnaceGUI::drawChanOsc() {
             }
 
             if (fft_->ready && e->isRunning()) {
-              chanOscWorkPool->push([this](void* fft_v) {
+              fft_->windowSize=chanOscWindowSize;
+              fft_->waveCorr=chanOscWaveCorr;
+              chanOscWorkPool->push([](void* fft_v) {
                 ChanOscStatus* fft=(ChanOscStatus*)fft_v;
                 DivDispatchOscBuffer* buf=fft->relatedBuf;
-                int ch=fft->relatedCh;
 
                 // the STRATEGY
                 // 1. FFT of windowed signal
@@ -433,7 +434,7 @@ void FurnaceGUI::drawChanOsc() {
 
                 // initialization
                 double phase=0.0;
-                int displaySize=(float)(buf->rate)*(chanOscWindowSize/1000.0f);
+                int displaySize=(float)(buf->rate)*(fft->windowSize/1000.0f);
                 fft->loudEnough=false;
                 fft->needle=buf->needle;
 
@@ -493,7 +494,7 @@ void FurnaceGUI::drawChanOsc() {
                   // did we find the period size?
                   if (fft->waveLen<(FURNACE_FFT_SIZE-32)) {
                     // we got pitch
-                    chanOscPitch[ch]=pow(1.0-(fft->waveLen/(double)(FURNACE_FFT_SIZE>>1)),4.0);
+                    fft->pitch=pow(1.0-(fft->waveLen/(double)(FURNACE_FFT_SIZE>>1)),4.0);
                     
                     fft->waveLen*=(double)displaySize*2.0/(double)FURNACE_FFT_SIZE;
 
@@ -511,7 +512,7 @@ void FurnaceGUI::drawChanOsc() {
                     // calculate and lock into phase
                     phase=(0.5+(atan2(dft[1],dft[0])/(2.0*M_PI)));
 
-                    if (chanOscWaveCorr) {
+                    if (fft->waveCorr) {
                       fft->needle-=phase*fft->waveLen;
                     }
                   }
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index 2dbe3f670..497aecace 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -1097,7 +1097,9 @@ float FurnaceGUI::calcBPM(const DivGroovePattern& speeds, float hz, int vN, int
 
 void FurnaceGUI::play(int row) {
   memset(chanOscVol,0,DIV_MAX_CHANS*sizeof(float));
-  memset(chanOscPitch,0,DIV_MAX_CHANS*sizeof(float));
+  for (int i=0; i<DIV_MAX_CHANS; i++) {
+    chanOscChan[i].pitch=0.0f;
+  }
   memset(chanOscBright,0,DIV_MAX_CHANS*sizeof(float));
   e->walkSong(loopOrder,loopRow,loopEnd);
   memset(lastIns,-1,sizeof(int)*DIV_MAX_CHANS);
@@ -3811,7 +3813,9 @@ bool FurnaceGUI::loop() {
     if (!e->isRunning()) {
       activeNotes.clear();
       memset(chanOscVol,0,DIV_MAX_CHANS*sizeof(float));
-      memset(chanOscPitch,0,DIV_MAX_CHANS*sizeof(float));
+      for (int i=0; i<DIV_MAX_CHANS; i++) {
+        chanOscChan[i].pitch=0.0f;
+      }
       memset(chanOscBright,0,DIV_MAX_CHANS*sizeof(float));
 
       e->synchronized([this]() {
@@ -7417,7 +7421,9 @@ FurnaceGUI::FurnaceGUI():
   memset(chanOscLP0,0,sizeof(float)*DIV_MAX_CHANS);
   memset(chanOscLP1,0,sizeof(float)*DIV_MAX_CHANS);
   memset(chanOscVol,0,sizeof(float)*DIV_MAX_CHANS);
-  memset(chanOscPitch,0,sizeof(float)*DIV_MAX_CHANS);
+  for (int i=0; i<DIV_MAX_CHANS; i++) {
+    chanOscChan[i].pitch=0.0f;
+  }
   memset(chanOscBright,0,sizeof(float)*DIV_MAX_CHANS);
   memset(lastCorrPos,0,sizeof(short)*DIV_MAX_CHANS);
 
diff --git a/src/gui/gui.h b/src/gui/gui.h
index eec988fca..a4bf28caa 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -2061,7 +2061,6 @@ class FurnaceGUI {
   float chanOscLP0[DIV_MAX_CHANS];
   float chanOscLP1[DIV_MAX_CHANS];
   float chanOscVol[DIV_MAX_CHANS];
-  float chanOscPitch[DIV_MAX_CHANS];
   float chanOscBright[DIV_MAX_CHANS];
   unsigned short lastNeedlePos[DIV_MAX_CHANS];
   unsigned short lastCorrPos[DIV_MAX_CHANS];
@@ -2074,8 +2073,9 @@ class FurnaceGUI {
     double inBufPosFrac;
     double waveLen;
     int waveLenBottom, waveLenTop, relatedCh;
+    float pitch, windowSize;
     unsigned short needle;
-    bool ready, loudEnough;
+    bool ready, loudEnough, waveCorr;
     fftw_plan plan;
     fftw_plan planI;
     ChanOscStatus():
@@ -2089,9 +2089,12 @@ class FurnaceGUI {
       waveLenBottom(0),
       waveLenTop(0),
       relatedCh(0),
+      pitch(0.0f),
+      windowSize(1.0f),
       needle(0),
       ready(false),
       loudEnough(false),
+      waveCorr(false),
       plan(NULL),
       planI(NULL) {}
   } chanOscChan[DIV_MAX_CHANS];