diff --git a/cmProc4.c b/cmProc4.c
new file mode 100644
index 0000000..db959a6
--- /dev/null
+++ b/cmProc4.c
@@ -0,0 +1,319 @@
+#include "cmPrefix.h"
+#include "cmGlobal.h"
+#include "cmRpt.h"
+#include "cmErr.h"
+#include "cmCtx.h"
+#include "cmMem.h"
+#include "cmMallocDebug.h"
+#include "cmLinkedHeap.h"
+#include "cmFloatTypes.h"
+#include "cmComplexTypes.h"
+#include "cmFileSys.h"
+#include "cmJson.h"
+#include "cmSymTbl.h"
+#include "cmAudioFile.h"
+#include "cmProcObj.h"
+#include "cmProcTemplate.h"
+#include "cmMath.h"
+#include "cmProc.h"
+#include "cmVectOps.h"
+#include "cmMidi.h"
+#include "cmMidiFile.h"
+#include "cmTimeLine.h"
+#include "cmScore.h"
+#include "cmProc4.h"
+
+
+
+cmScFol* cmScFolAlloc( cmCtx* c, cmScFol* p, cmReal_t srate, unsigned wndN, cmReal_t wndMs, cmScH_t scH )
+{
+  cmScFol* op = cmObjAlloc(cmScFol,c,p);
+  if( srate != 0 )
+    if( cmScFolInit(op,srate,wndN,wndMs,scH) != cmOkRC )
+      cmScFolFree(&op);
+  return op;
+}
+
+cmRC_t   cmScFolFree(  cmScFol** pp )
+{
+  cmRC_t rc = cmOkRC;
+  if( pp==NULL || *pp==NULL )
+    return rc;
+
+  cmScFol* p = *pp;
+  if((rc = cmScFolFinal(p)) != cmOkRC )
+    return rc;
+
+  unsigned i;
+  for(i=0; i<p->locN; ++i)
+    cmMemFree(p->loc[i].pitchV);
+
+  cmMemFree(p->loc);
+  cmObjFree(pp);
+  return rc;
+}
+
+
+cmRC_t   cmScFolFinal( cmScFol* p )
+{ return cmOkRC; }
+
+void _cmScFolPrint( cmScFol* p )
+{
+  int i,j;
+  for(i=0; i<p->locN; ++i)
+  {
+    printf("%2i %5i ",p->loc[i].barNumb,p->loc[i].evtIdx);
+    for(j=0; j<p->loc[i].pitchCnt; ++j)
+      printf("%s ",cmMidiToSciPitch(p->loc[i].pitchV[j],NULL,0));
+    printf("\n");
+  }
+}
+
+cmRC_t   cmScFolInit(  cmScFol* p, cmReal_t srate, unsigned wndN, cmReal_t wndMs, cmScH_t scH )
+{
+  cmRC_t rc;
+  if((rc = cmScFolFinal(p)) != cmOkRC )
+    return rc;
+
+  p->srate          = srate;
+  p->scH            = scH;
+  p->maxWndSmp      = floor(wndMs * srate / 1000.0);
+  p->wndN           = wndN;
+  p->wndV           = cmMemResizeZ(cmScFolWndEle_t,p->wndV,wndN);
+  p->locN           = cmScoreEvtCount(scH);
+  p->loc            = cmMemResizeZ(cmScFolLoc_t,p->loc,p->locN);
+  p->sri            = cmInvalidIdx;
+  p->sbi            = cmInvalidIdx;
+  p->sei            = cmInvalidIdx;
+  p->edWndMtx       = cmVOU_LevEditDistAllocMtx(p->wndN);
+  p->evalWndN       = 5;
+  p->allowedMissCnt = 1;
+
+  assert(p->evalWndN<p->wndN);
+
+  int i,n;
+  double        maxDSecs = 0;   // max time between events to be considered simultaneous
+  cmScoreEvt_t* e0p      = NULL;
+  int           j0       = 0;
+
+  // for each score event
+  for(i=0,n=0; i<p->locN; ++i)
+  {
+    cmScoreEvt_t* ep = cmScoreEvt(scH,i);
+
+    // if the event is not a note then ignore it
+    if( ep->type == kNonEvtScId )
+    {
+      assert( j0+n < p->locN );
+
+      p->loc[j0+n].evtIdx  = i;
+      p->loc[j0+n].barNumb = ep->barNumb;
+
+      // if the first event has not yet been selected
+      if( e0p == NULL )
+      {
+        e0p = ep;
+        n   = 1;
+      }
+      else
+      {
+        // time can never reverse
+        assert( ep->secs >= e0p->secs );  
+
+        // calc seconds between first event and current event
+        double dsecs = ep->secs - e0p->secs;
+
+        // if the first event and current event are simultaneous...
+        if( dsecs <= maxDSecs )
+          ++n;   // ... incr. the count of simultaneous events
+        else
+        {
+          int k;
+          //  ... a complete set of simultaneous events have been located
+          // duplicate all the events at each of their respective time locations
+          for(k=0; k<n; ++k)
+          {
+            int m;
+            assert( j0+k < p->locN );
+
+            p->loc[j0+k].pitchCnt = n;
+            p->loc[j0+k].pitchV   = cmMemAllocZ(unsigned,n);
+
+            for(m=0; m<n; ++m)
+            {
+              cmScoreEvt_t* tp = cmScoreEvt(scH,p->loc[j0+m].evtIdx);
+              assert(tp!=NULL);
+              p->loc[j0+k].pitchV[m] = tp->pitch;
+            }
+          }
+          
+          e0p = ep;
+          j0 += n;
+          n   = 1;
+        }
+      }
+    }
+  }
+
+  p->locN = j0;
+
+  //_cmScFolPrint(p);
+
+  return rc;
+}
+
+cmRC_t   cmScFolReset(   cmScFol* p, unsigned scoreIndex )
+{
+  int i;
+
+  // zero the event index
+  memset(p->wndV,0,sizeof(cmScFolWndEle_t)*p->wndN);
+
+  // don't allow the score index to be prior to the first note
+  if( scoreIndex < p->loc[0].evtIdx )
+    scoreIndex = p->loc[0].evtIdx;
+
+  // locate the score element in svV[] that is closest to,
+  // and possibly after, scoreIndex.
+  for(i=0; i<p->locN-1; ++i)
+    if( p->loc[i].evtIdx <= scoreIndex && scoreIndex < p->loc[i+1].evtIdx  )
+      break;
+
+  // force scEvtIndex to be valid
+  assert( i<p->locN );
+
+  p->sri = i;
+  p->sbi = i;
+
+  // score event window is dBar bars before and after scEvtIndex;
+  int dBar = 1;
+
+  // backup dBar bars from the 'scoreIndex'
+  for(; i>=0; --i)
+    if( p->loc[i].barNumb >= (p->loc[p->sri].barNumb-dBar) ) 
+      p->sbi = i;
+    else
+      break;
+  
+  dBar = 3;
+
+  // move forward dBar bars from 'scoreIndex'
+  for(i=p->sri; i<p->locN; ++i)
+    if( p->loc[i].barNumb <= (p->loc[p->sri].barNumb+dBar) )
+      p->sei = i;
+    else
+      break;
+
+  return cmOkRC;
+}
+
+bool  _cmScFolIsMatch( const cmScFolLoc_t* loc, unsigned pitch )
+{
+  unsigned i;
+  for(i=0; i<loc->pitchCnt; ++i)
+    if( loc->pitchV[i] == pitch )
+      return true;
+  return false;
+}
+
+int _cmScFolDist(unsigned mtxMaxN, unsigned* m, const unsigned* s1, const cmScFolLoc_t* s0, int n )
+{
+  mtxMaxN += 1;
+
+  assert( n < mtxMaxN );
+  
+  int			  v		= 0;
+  unsigned  i;
+  // Note that m[maxN,maxN] is not oriented in column major order like most 'cm' matrices.
+
+  for(i=1; i<n+1; ++i)
+  {
+    unsigned ii 	= i  * mtxMaxN;	// current row
+    unsigned i_1 	= ii - mtxMaxN;	// previous row
+    unsigned j;	
+    for( j=1; j<n+1; ++j)
+    {
+      //int cost = s0[i-1] == s1[j-1] ? 0 : 1;
+      int cost = _cmScFolIsMatch(s0 + i-1, s1[j-1]) ? 0 : 1;
+
+      //m[i][j] = min( m[i-1][j] + 1, min( m[i][j-1] + 1, m[i-1][j-1] + cost ) );
+					
+      m[ ii + j ] = v = cmMin( m[ i_1 + j] + 1, cmMin( m[ ii + j - 1] + 1, m[ i_1 + j - 1 ] + cost ) );
+    }
+  }	
+  return v;		
+}
+
+
+unsigned   cmScFolExec(  cmScFol* p, unsigned smpIdx, unsigned status, cmMidiByte_t d0, cmMidiByte_t d1 )
+{
+  assert( p->sri != cmInvalidIdx );
+
+  unsigned ret_idx = cmInvalidIdx;
+  unsigned ewnd[ p->wndN ];
+
+  if( status != kNoteOnMdId && d1>0 )
+    return ret_idx;
+
+  // left shift wndV[] to make the right-most element available - then copy in the new element
+  memmove(p->wndV, p->wndV+1, sizeof(cmScFolWndEle_t)*(p->wndN-1));
+  p->wndV[ p->wndN-1 ].smpIdx = smpIdx;
+  p->wndV[ p->wndN-1 ].val    = d0;
+  p->wndV[ p->wndN-1 ].validFl= true;
+
+  // fill in ewnd[] with the valid values in wndV[]
+  int i = p->wndN-1;
+  int en = 0;
+  for(; i>=0; --i,++en)
+  {
+    if( p->wndV[i].validFl /*&& ((smpIdx-p->wnd[i].smpIdx)<=maxWndSmp)*/)
+      ewnd[i] = p->wndV[i].val;
+    else
+      break;
+  }
+  ++i; // increment i to the first valid element in ewnd[].
+
+  int k;
+  printf("en:%i sbi:%i sei:%i pitch:%s : ",en,p->sbi,p->sei,cmMidiToSciPitch(d0,NULL,0));
+  for(k=i; k<p->wndN; ++k)
+    printf("%s ", cmMidiToSciPitch(ewnd[k],NULL,0));
+  printf("\n");
+
+  // en is the count of valid elements in ewnd[].
+  // ewnd[i] is the first valid element
+
+  int    j       = 0;
+  int    dist;
+  int    minDist = INT_MAX;
+  int    minIdx  = cmInvalidIdx;
+  for(j=0; p->sbi+en+j <= p->sei; ++j)
+    if((dist = _cmScFolDist(p->wndN, p->edWndMtx, ewnd+i, p->loc + p->sbi+j, en )) < minDist )
+    {
+      minDist = dist;
+      minIdx  = j;
+    }
+
+  // The best fit is on the score window: p->loc[sbi+minIdx : sbi+minIdx+en-1 ]
+   
+  int evalWndN = cmMin(en,p->evalWndN);
+
+  assert(evalWndN<p->wndN);
+  
+  j = p->sbi+minIdx+en - evalWndN;
+
+  // Determine how many of the last evalWndN elements match
+  dist =  _cmScFolDist(p->wndN, p->edWndMtx, ewnd+p->wndN-evalWndN, p->loc+j, evalWndN );
+  
+  // a successful match has <= allowedMissCnt and an exact match on the last element  
+  //if( dist <= p->allowedMissCnt && ewnd[p->wndN-1] == p->loc[p->sbi+minIdx+en-1] )
+  if( /*dist <= p->allowedMissCnt &&*/ _cmScFolIsMatch(p->loc+(p->sbi+minIdx+en-1),ewnd[p->wndN-1]))
+  {
+    p->sbi  = p->sbi + minIdx;
+    p->sei  = cmMin(p->sei+minIdx,p->locN-1);
+    ret_idx = p->sbi+minIdx+en-1;
+  }
+
+  printf("minDist:%i minIdx:%i evalDist:%i sbi:%i sei:%i\n",minDist,minIdx,dist,p->sbi,p->sei);
+
+  return ret_idx;
+}
diff --git a/cmProc4.h b/cmProc4.h
new file mode 100644
index 0000000..a2d1748
--- /dev/null
+++ b/cmProc4.h
@@ -0,0 +1,64 @@
+#ifndef cmProc4_h
+#define cmProc4_h
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+
+typedef struct
+{
+  unsigned     smpIdx;  // time tag sample index for val
+  cmMidiByte_t val;     //
+  bool         validFl; //
+  
+} cmScFolWndEle_t;
+
+typedef struct
+{
+  unsigned  pitchCnt; // 
+  unsigned* pitchV;   // pitchV[pitchCnt]
+  unsigned  evtIdx;   // index of the score event (into cmScoreEvt[]) at this location 
+  int       barNumb;  // bar number of this location
+} cmScFolLoc_t;
+
+
+typedef struct
+{
+  cmObj            obj;
+  cmReal_t         srate;
+  cmScH_t          scH;
+  unsigned         maxWndSmp;
+  unsigned         wndN;
+  cmScFolWndEle_t* wndV;     // wnd[wndN]
+  int              wni;     // oldest value in wnd[]
+  int              locN;
+  cmScFolLoc_t*    loc;
+  unsigned         sri;     // last reset score index
+  unsigned         sbi;     // first (oldest) score index
+  unsigned         sei;     // last (newest) score index
+
+  unsigned         evalWndN; // (dflt:5) count of elements to use for refined match window
+  unsigned         allowedMissCnt; // (dflt:1) count of non-match elements in refined match where a match is still signaled
+
+  unsigned*        edWndMtx;
+  
+} cmScFol;
+
+// wndN = max count of elements in the  score following window.
+  // wndMs     = max length of the score following window in time
+
+cmScFol* cmScFolAlloc( cmCtx* ctx, cmScFol* p, cmReal_t srate, unsigned wndN, cmReal_t wndMs, cmScH_t scH );
+cmRC_t   cmScFolFree(  cmScFol** pp );
+cmRC_t   cmScFolInit(  cmScFol* p, cmReal_t srate, unsigned wndN, cmReal_t wndMs, cmScH_t scH );
+cmRC_t   cmScFolFinal( cmScFol* p );
+cmRC_t   cmScFolReset( cmScFol* p, unsigned scoreIndex );
+unsigned cmScFolExec(  cmScFol* p, unsigned smpIdx, unsigned status, cmMidiByte_t d0, cmMidiByte_t d1 );
+  
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif