Next frame mode is kind of working, though it sometimes return 2 frames...

src/Workflow/MainWorkflow.cpp

@@ -48,6 +48,7 @@ MainWorkflow::MainWorkflow( QObject* parent, int trackCount ) :
         connect( m_tracks[i], SIGNAL( trackEndReached( unsigned int ) ), this, SLOT( trackEndReached(unsigned int) ) );
     }
     m_renderStartedLock = new QReadWriteLock;
+    m_lastRenderedFrame = MainWorkflow::blackOutput;
 }
 
 MainWorkflow::~MainWorkflow()
@@ -91,7 +92,13 @@ void    MainWorkflow::startRender()
 unsigned char*    MainWorkflow::getOutput()
 {
     QReadLocker     lock( m_renderStartedLock );
+    qDebug() << "New frame asked";
 
+    if ( m_renderOnlyOneFrame == 1 && m_lastRenderedFrame != NULL )
+    {
+        qDebug() << "Returning last frame";
+        return m_lastRenderedFrame;
+    }
     if ( m_renderStarted == true )
     {
         unsigned char* ret;
@@ -106,11 +113,16 @@ unsigned char*    MainWorkflow::getOutput()
         if ( ret == NULL )
             ret = MainWorkflow::blackOutput;
 
-        nextFrame();
+        if ( m_renderOnlyOneFrame == 0 )
+            nextFrame();
+        m_lastRenderedFrame = ret;
         return ret;
     }
     else
+    {
+        m_lastRenderedFrame = MainWorkflow::blackOutput;
         return MainWorkflow::blackOutput;
+    }
 }
 
 void        MainWorkflow::pause()
@@ -124,6 +136,7 @@ void        MainWorkflow::pause()
 
 void        MainWorkflow::nextFrame()
 {
+    qDebug() << "Going to next frame";
     ++m_currentFrame;
     //FIXME: This is probably a bit much...
     emit frameChanged( m_currentFrame );
@@ -218,3 +231,9 @@ void           MainWorkflow::clipMoved( QUuid clipUuid, int oldTrack, int newTra
         m_tracks[newTrack].activate();
     }
 }
+
+void        MainWorkflow::activateOneFrameOnly()
+{
+    m_renderOnlyOneFrame = 1;
+//    m_lastRenderedFrame = NULL;
+}

src/Workflow/MainWorkflow.h

@@ -26,6 +26,8 @@
 
 #include <QObject>
 #include <QReadWriteLock>
+#include <QAtomicInt>
+#include <QAtomicPointer>
 
 #include "tools/Toggleable.hpp"
 #include "TrackWorkflow.h"
@@ -73,6 +75,13 @@ class   MainWorkflow : public QObject, public Singleton<MainWorkflow>
         static unsigned char*   blackOutput;
         void                    nextFrame();
         void                    previousFrame();
+
+        /**
+         *  \brief  By calling this method, you ensure that the MainWorkflow will
+         *          only return one frame to you, until you restore the normal render mode,
+         *          or until you call this method again.
+         */
+        void                    activateOneFrameOnly();
         
         static MainWorkflow*    getInstance();
 
@@ -89,6 +98,14 @@ class   MainWorkflow : public QObject, public Singleton<MainWorkflow>
         bool                            m_renderStarted;
         QReadWriteLock*                 m_renderStartedLock;
 
+        /**
+         *  \brief  This will be used in case of next frame, to avoid rendering more than one frame
+         *          at a time
+         */
+        QAtomicPointer<unsigned char>   m_lastRenderedFrame;
+
+        QAtomicInt                      m_renderOnlyOneFrame;
+
     public slots:
         void                            clipMoved( QUuid, int, int, qint64 );
 

src/Workflow/TrackWorkflow.cpp

@@ -246,7 +246,7 @@ unsigned char*      TrackWorkflow::getOutput( qint64 currentFrame )
             m_forceRepositionning = false;
         }
         else
-            needRepositioning = ( abs( currentFrame - lastFrame ) > 1 ) ? true : false;
+            needRepositioning = ( currentFrame - lastFrame != 1 ) ? true : false;
     }
     while ( it != end )
     {

src/gui/RenderPreviewWidget.cpp

@@ -127,7 +127,11 @@ void        RenderPreviewWidget::nextFrame()
         QWriteLocker    lock( m_framePlayedLock );
         m_framePlayed = false;
     }
+    //FIXME: MainWorkflow should be paused
     m_mainWorkflow->nextFrame();
+    qDebug() << "Activated one frame only";
+    m_mainWorkflow->activateOneFrameOnly();
+    m_mainWorkflow->pause();
     m_mediaPlayer->play();
     bool    framePlayed = false;
     while ( framePlayed == false )
@@ -137,6 +141,7 @@ void        RenderPreviewWidget::nextFrame()
         framePlayed = m_framePlayed;
     }
     m_mediaPlayer->pause();
+    m_mainWorkflow->pause();
 }
 
 void        RenderPreviewWidget::previousFrame()