Can I use an iMac in target display mode with an Apple TV?
Displayport is the protocol for video over thunderbolt.


https://www.apple.com/thunderbolt/




http://www.cablestogo.com/product/54179/hdmi-to-displayport-adapter-converter

Get the above converter and then connect the cables with whatever cheap adapters and cables are required to fit all the physical connections. All told, less than $200 of cables and adapters are needed to do what you ask.

Basically, you have a video capture station/tiny computer resampling the HDMI signal and re-encoding it into the DisplayPort format.