I've been researching methods of getting an IP Multicast over UDP to the browser, and have found little that suggests I would be able to do it without using a plug-in like Java, Flash, or Silverlight in order to open a UDP port and (somehow) render the video. Checking out the HTML 5 <video> spec, there is (obviously) little in the way of specific implementation details, so as far as I can tell, there is nothing stopping a browser from parsing a address of the form "udp://224.1.1.1:8000" and joining a multicast group on that IP/port. Is this a correct understanding? Or must the resource pointed to by the <source> be a file?