Q:

API to use XBox 360 as extender / enable UPnP AV Transport on XBox

What I want to achieve is to be able to tell the XBox 360 to play a HTTP / MP3 stream from some server and I want to control this remotely (i.e. not use the XBox controller / TV screen).
I know there is UPnP media servers that are detected by the XBox, but those require some setup and the main problem is that I would have to use my xbox to play the music. 
I want to build an Android App that can stream to the XBox while I control everything from the app. As such my idea is to run a HTTP server on the phone, detect the XBox and tell it to play the http URL which points back to the phone.
I can find the XBox UPnP MediaRenderer interface, but it is not advertising the AVTransport Service (which is needed). I have tried the same thing with XBMC and it works (XBMC does have the AVTransport).
Windows Media Center does use XBox as Extender, so it must be possible. The question is how. Maybe there is an Extender setup handshake that enables the AVTransport feature?

A:

This guy says that "protocols used between the extender and the media center are partially open" and gives some links to MSDN. But nothing like a hidden AVTransport interface which comes up after the device pairing, i'm afraid. No hope for something as embarassingly boring as standard SetAVTransportURI. The communication seems to be carried over "Remote Desktop Protocol channels" (whatever that is), which lefts me confused about why Microsoft bothered to implement MediaRenderer at all. Another shot at "embrace, extend, extinguish", i guess. Which is hilariously recursive because UPnP is based on Microsoft-invented SSDP.
Any way, it's apparently a hardcore reverse engineering, packet capturing being a prominent tool. There is another project referenced from that page, aiming at recreating Media Center - basically what you would like to have. But stalled for almost 3 years. I think you're free to pick up :)

