About the subtitleshttp://mediatomb.cc/dokuwiki/transcoding:transcoding
it is possible with mediatomb. Ill will take a look at where the config will go for it, but I cant promise it will be soon as im on a project for the next 11 days. Also, I would recommend looking into how robust upnp support is for the tv you select. This will give you an idea of how good or bad the implementation is.
Also, expect to spend some time hacking around with the config settings. It seems like everybody and their mom has specific flags for their damned device to enable things like video thumbnails, cover art, trans-coding, etc. I wont claim that im a master of mediatomb, but I have been able to bend it to my will to get the little details on my ps3 enabled, so if you post in the forum or find me in irc, im more than happy to help.
Lastly, mediatomb is theoretically going away for something sexier. But that requires knowledge of python, which is coming slowly. So if any of you know some python and have an interest in making a better upnp server, please drop me a message. In the mean time, enjoy mediatomb
sorry didn't mean to hijack the thread