Fixed deadlock when mutting the only track that had something to render.

src/Tools/Toggleable.hpp

@@ -57,6 +57,10 @@ class   Toggleable
         {
             return ( m_hardDeactivated == true || m_activated == false );
         }
+        bool    hardDeactivated() const
+        {
+            return m_hardDeactivated;
+        }
         void    activate()
         {
             m_activated = true;

src/Workflow/TrackHandler.cpp

@@ -106,7 +106,13 @@ void        TrackHandler::getOutput( qint64 currentFrame )
     {
         if ( m_tracks[i].activated() == false )
         {
-            m_effectEngine->setInputFrame( *TrackHandler::nullOutput, i );
+            if ( m_tracks[i].hardDeactivated() == true )
+            {
+                ++m_nbTracksToRender;
+                m_tracks[i]->simulateBlackOutputRender();
+            }
+            else
+                m_effectEngine->setInputFrame( *TrackHandler::nullOutput, i );
             continue ;
         }
         ++m_nbTracksToRender;

src/Workflow/TrackWorkflow.cpp

@@ -633,3 +633,8 @@ void    TrackWorkflow::forceRepositionning()
     QMutexLocker    lock( m_forceRepositionningMutex );
     m_forceRepositionning = true;
 }
+
+void    TrackWorkflow::simulateBlackOutputRender()
+{
+    clipWorkflowRenderCompleted( NULL );
+}

src/Workflow/TrackWorkflow.h

@@ -79,6 +79,12 @@ class   TrackWorkflow : public QObject
         void                                    setFullSpeedRender( bool value );
         void                                    forceRepositionning();
 
+        /**
+         *  \brief          This method is only to simulate a track render, which will render a black output.
+         *                  this is meant to render a muted track, though the Qt event loop (QueuedConnection signal)
+         */
+        void                                    simulateBlackOutputRender();
+
     private:
         void                                    computeLength();
         void                                    renderClip( ClipWorkflow* cw, qint64 currentFrame,