Nice summary Bob.
What is the functional distinction between a DLNA renderer and a DLNA client?
I can't find an authoritative definition quickly, probably because DLNA.org has been dissolved and a lot of good information is scattered around the web, but the distinction as I understand it is that a "DLNA Client" consists of a DLNA Renderer and a DLNA Controller in one hardware or software unit.
The main components of DLNA are;
DLNA Server
DLNA Renderer
DLNA Controller
Those components can be turned on individually in MC, but most devices such as your TV include both the Renderer and Controller together, with no way to turn either part off.
The situation with VLC seems a little confusing, as it does seem to act as a DLNA Client, but the definition of Client is a little loose. I tested it. See
https://www.vlchelp.com/access-media-upnp-dlna/ However, what I think VLC actually could be categorised as is a DLNA Controller and a local Player, rather than a DLNA Renderer. In other words, it can read content from a DLNA Server and theoretically send content to a DLNA Renderer, but it is not a DLNA Renderer itself. Hence it doesn't show up in MC as an available Zone/Renderer. BubbleUPnP also cannot see VLC as a DLNA Renderer, and BubbleUPnP is very good at finding Renderers. The
Whitebear Digital Media Renderer Analyser also couldn't find VLC, although it could find my TV and BubbleUPnP no problem. So I have to conclude the VLC doesn't advertise itself as a Renderer, and I couldn't find any settings that made it do so. Mind you, I'm not a VLC expert.
Also, note that I could not get VLC to play to an instance of MC running as a DLNA Renderer. It found the Renderer okay, although it replicated it up to four times without distinction. It seemed to be trying to play to the Renderer. But it never played anything. It couldn't even find the BubbleUPnP Renderer. Maybe I have an old version of VLC... nope. Finally, VLC calls itself a Media Player, not a Renderer.
Are you sure Universal Media Server displays VLC as a DLNA Renderer? This post would imply it does not:
https://www.universalmediaserver.com/forum/viewtopic.php?f=9&t=14081&p=41209&hilit=VLC#p41209"VLC is not visible as dlna renderer". Perhaps if you have configured UMC to find the VLC exe directly, as per
https://www.universalmediaserver.com/forum/viewtopic.php?f=5&t=13419&p=41246&hilit=VLC#p41246Google is your friend for more detail. If you can find the right reference!
If you want more help, please describe all the devices in your setup, including brand and model for the hardware devices. i.e. We now know that you have two hardware devices in the TV and the bedroom radio, and I think you have a couple of PCs running as MC Clients?
Also;
As a side issue, when MC is operating as a client, where do you get the list of items the server has on offer? Do you have to configure a library server? Using VLC as a client, you are presented with an obvious tree as defined within "DLNA Servers/customize views". But as I said, that's a side issue.
Huh?
Have you learned how the MC Client/Server setup works?
https://wiki.jriver.com/index.php/Media_Networkhttps://wiki.jriver.com/index.php/Media_Serverhttps://wiki.jriver.com/index.php/Libraryhttps://wiki.jriver.com/index.php/DLNAA MC Client is a lot more than just a DLNA Client. Sure, it uses components of DLNA, but a MC Server matched with a MC Client allows updates back to the Server, stores a local copy of the Server Library so that it doesn't have to query a DLNA Server and is therefore much faster than a DLNA Server, and... well, read the Wiki and Forum.