I have been working on getting my LG LCD TV plug and play and I have been building a template. First off Thank you for your wiki page, as it did help getting things started. I have also ran into this issue of no media typed defined. And from what I can tell, this is set in the Audio/Visual Properties on the Main Device Template and it can actually be changed after the creation of a template without manual SQL command.
from the edit Device Template page click the edit Audio/Visual Properties button, which will bring up a new window where you can make changes to ruby/ir codes, but at the top you can also make changes to the inputs for the template. click change/explain. This will bring up a long list of possible inputs, which I am sure you are familiar with.
Now here you can tell the template which input is associated with which media type or associate the input with an external device, which I would assume would then assign the media type. The notes on the bottom of the page state:
REMEMBER: If the device has a built-in source of media on that input, be sure you choose it from the 'source' list. For example, if you have a receiver, normally the 'am' and 'fm' inputs have a built in source (over the air radio), but the 'cd' input is for an external device. If you have a TV, normally the 'tuner' input is a built-in source (live tv) and video 1, 2, etc. are external. For VCR's there are normally only 2 inputs, tuner and VHS, and both have built-in sources (Live tv and videotape). You may have a combo unit that has lots of built-in sources, like a built-in radio, vcr, dvd. In that case be sure to indicate which inputs have built-in sources vs. external. You don't need to specify the connector type if you don't know it; it's only used when displaying a visual diagram of your equipment's connections.
Here is where I am a little confused, and I will likely start a new thread for this one, but I will ask here as it may also apply more globally. As I build the new template, I assign the proper media type to the inputs with built in tuners, and I leave the selection as external device when I anticipate hooking up a device, but this does not seem to work, ie no media type is defined. I had to define my input AV1 as LiveTV even though it is connected to my Motorola DCT2000 Box, which I also created a template for and assigned it the media type of CableRadio.
Do you know if this is a bug or if I am just getting things confused, which is entirely possible.
I am working on documenting my experience of building the LG template and making the TV plug and play. I will put it on the wiki as soon as I confirm it actually works as expected.