public void RenderUrl2(string fileUrl1, string fileUrl2, IntPtr videoHwnd)
{
this.videoHwnd = videoHwnd;
var tempSource = CreateMediaSource(fileUrl1);
var tempSource2 = CreateMediaSource(fileUrl2);
Collection mediaCollection;
MediaFactory.CreateCollection(out mediaCollection);
mediaCollection.AddElement(tempSource);
mediaCollection.AddElement(tempSource2);
MediaFactory.CreateAggregateSource(mediaCollection, out mediaSource);
CreateTopology();
}