private void MarkVideoRange(string inOut)
 {
     try
     {
         if (inOut == "In")
         {
             SelectionStart = SliderValue;
             StartTime      = _mediaElement.GetCurrentPosition();
         }
         else if (inOut == "Out")
         {
             SelectionEnd = SliderValue;
             EndTime      = _mediaElement.GetCurrentPosition();
         }
     }
     catch { }
 }