Fix bug #1663444

src/engine/bpmcontrol.cpp

@@ -567,7 +567,7 @@ bool BpmControl::getBeatContextNoLookup(
     return true;
 }
 
-double BpmControl::getNearestPositionInPhase(double dThisPosition, bool respectLoops) {
+double BpmControl::getNearestPositionInPhase(double dThisPosition, bool respectLoops, bool playing) {
     // Without a beatgrid, we don't know the phase offset.
     if (!m_pBeats) {
         return dThisPosition;
@@ -609,6 +609,14 @@ double BpmControl::getNearestPositionInPhase(double dThisPosition, bool respectL
             return dThisPosition;
         }
 
+        if (playing) {
+            // "this" track is playing, or just starting
+            // only match phase if the sync target is playing as well
+            if (pOtherEngineBuffer->getSpeed() == 0.0) {
+                return dThisPosition;
+            }
+        }
+
         TrackPointer otherTrack = pOtherEngineBuffer->getLoadedTrack();
         BeatsPointer otherBeats = otherTrack ? otherTrack->getBeats() : BeatsPointer();
 
@@ -693,7 +701,7 @@ double BpmControl::getNearestPositionInPhase(double dThisPosition, bool respectL
                 // Move new position after loop jump into phase as well.
                 // This is a recursive call, called only twice because of
                 // respectLoops = false
-                dNewPlaypos = getNearestPositionInPhase(dNewPlaypos, false);
+                dNewPlaypos = getNearestPositionInPhase(dNewPlaypos, false, playing);
             }
 
             // Note: Syncing to before the loop beginning is allowed, because
@@ -706,7 +714,7 @@ double BpmControl::getNearestPositionInPhase(double dThisPosition, bool respectL
 
 double BpmControl::getPhaseOffset(double dThisPosition) {
     // This does not respect looping
-    double dNewPlaypos = getNearestPositionInPhase(dThisPosition, false);
+    double dNewPlaypos = getNearestPositionInPhase(dThisPosition, false, false);
     return dNewPlaypos - dThisPosition;
 }
 

src/engine/bpmcontrol.h

@@ -33,7 +33,7 @@ class BpmControl : public EngineControl {
     // out of sync.
     double calcSyncedRate(double userTweak);
     // Get the phase offset from the specified position.
-    double getNearestPositionInPhase(double dThisPosition, bool respectLoops = true);
+    double getNearestPositionInPhase(double dThisPosition, bool respectLoops, bool playing);
     double getPhaseOffset(double dThisPosition);
     double getBeatDistance(double dThisPosition) const;
     double getPreviousSample() const { return m_dPreviousSample; }

src/engine/enginebuffer.cpp

@@ -1165,7 +1165,7 @@ void EngineBuffer::processSeek(bool paused) {
     }
 
     if ((seekType & SEEK_PHASE) && !paused && m_pQuantize->toBool()) {
-        position = m_pBpmControl->getNearestPositionInPhase(position);
+        position = m_pBpmControl->getNearestPositionInPhase(position, true, true);
     }
 
     double newPlayFrame = position / kSamplesPerFrame;

src/engine/sync/enginesync.cpp

@@ -381,7 +381,7 @@ EngineChannel* EngineSync::pickNonSyncSyncTarget(EngineChannel* pDontPick) const
             EngineBuffer* pBuffer = pChannel->getEngineBuffer();
             if (pBuffer && pBuffer->getBpm() > 0) {
                 // If the deck is playing then go with it immediately.
-                if (fabs(pBuffer->getSpeed()) > 0) {
+                if (pBuffer->getSpeed() != 0.0) {
                     return pChannel;
                 }
                 // Otherwise hold out for a deck that might be playing but