public static IBaseFilter AddToFilterGraph(FilterDefinition fd, ref IGraphBuilder graph, string _graphDisplayName)
 {
     if (fd.HasDevicePath)
         return FilterGraphTools.AddFilterByDevicePath(graph, fd.DevicePath, _graphDisplayName);
     else
         if (fd.CLSID != Guid.Empty)
             return FilterGraphTools.AddFilterFromClsid(graph, fd.CLSID, _graphDisplayName);
         else
             return null;
 }
 // Add to filter graph
 public static IBaseFilter AddToFilterGraph(FilterDefinition fd, ref IGraphBuilder graph)
 {
     return AddToFilterGraph(fd, ref graph, fd.DisplayString);
 }