fix for volumeslider crash when no video loaded

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>

src/Renderer/ClipRenderer.cpp

@@ -147,10 +147,14 @@ ClipRenderer::getVolume() const
     return m_sourceRenderer->volume();
 }
 
-void ClipRenderer::setVolume( int volume )
+void
+ClipRenderer::setVolume( int volume )
 {
     //Returns 0 if the volume was set, -1 if it was out of range
-    return m_sourceRenderer->setVolume( volume );
+    if( m_isRendering == true )
+    {
+        return m_sourceRenderer->setVolume( volume );
+    }
 }
 
 void

src/Renderer/WorkflowRenderer.cpp

@@ -274,10 +274,14 @@ WorkflowRenderer::getVolume() const
     return m_sourceRenderer->volume();
 }
 
-void WorkflowRenderer::setVolume( int volume )
+void
+WorkflowRenderer::setVolume( int volume )
 {
     //Returns 0 if the volume was set, -1 if it was out of range
-    m_sourceRenderer->setVolume( volume );
+    if( m_isRendering == true )
+    {
+        m_sourceRenderer->setVolume( volume );
+    }
 }
 
 qint64