There is no way to capture DVD using sample grabber (ImageEn is not a DVD ripper).
You can only capture a sample using GetSample method, as shown in Display\VMR_DVD example:
with ImageEnView1.IO.DShowParams do
begin
GetSample( ImageEnView1.IEBitmap );
ImageEnView1.Update;
ImageEnMView1.AppendImage( ImageEnView1.IEBitmap );
end;