diff --git a/source/app/SubWindowHandle.cpp b/source/app/SubWindowHandle.cpp
index c54467e..1e08a1e 100644
--- a/source/app/SubWindowHandle.cpp
+++ b/source/app/SubWindowHandle.cpp
@@ -208,9 +208,17 @@ Bool SubWindowHandle::save( QString filename )
   return iRet;
 }
 
-Void SubWindowHandle::play()
+Bool SubWindowHandle::play()
 {
-  m_bIsPlaying = true;
+  if( m_pCurrStream && m_pCurrStream->getFrameNum() > 1 )
+  {
+    m_bIsPlaying = true;
+  }
+  else
+  {
+    m_bIsPlaying = false;
+  }
+  return m_bIsPlaying;
 }
 
 Int SubWindowHandle::playEvent()
diff --git a/source/app/SubWindowHandle.h b/source/app/SubWindowHandle.h
index e58b392..6a68ba2 100644
--- a/source/app/SubWindowHandle.h
+++ b/source/app/SubWindowHandle.h
@@ -70,7 +70,7 @@ public:
   Void reloadFile();
   Bool save( QString filename  );
 
-  Void play();
+  Bool play();
   Void pause();
   Int playEvent();
   Void stop();
diff --git a/source/app/plaYUVerApp.cpp b/source/app/plaYUVerApp.cpp
index a0e1627..09ceea2 100644
--- a/source/app/plaYUVerApp.cpp
+++ b/source/app/plaYUVerApp.cpp
@@ -456,29 +456,26 @@ Void plaYUVerApp::play()
 
   if( m_arrayActions[VIDEO_LOCK_ACT]->isChecked() && m_acPlayingSubWindows.size() )
   {
-    Bool bFind = false;
-    for( Int i = 0; i < m_acPlayingSubWindows.size(); i++ )
+    if( !m_acPlayingSubWindows.contains( m_pcCurrentSubWindow ) )
     {
-      if( m_acPlayingSubWindows.at( i ) == m_pcCurrentSubWindow )
+      if( !m_pcCurrentSubWindow->play() )
       {
-        bFind = true;
-        break;
+        return;
       }
-    }
-    if( !bFind )
-    {
       m_acPlayingSubWindows.append( m_pcCurrentSubWindow );
       m_pcCurrentSubWindow->seekAbsoluteEvent( m_acPlayingSubWindows.at( 0 )->getInputStream()->getCurrFrameNum() );
       updateTotalFrameNum();
     }
-    m_pcCurrentSubWindow->play();
   }
   else
   {
     m_pcPlayingTimer->stop();
     m_acPlayingSubWindows.clear();
+    if( !m_pcCurrentSubWindow->play() )
+    {
+      return;
+    }
     m_acPlayingSubWindows.append( m_pcCurrentSubWindow );
-    m_pcCurrentSubWindow->play();
     m_uiAveragePlayInterval = 0;
     m_bIsPlaying = false;
   }