Hi pigbait,
Did you manage to get this working? Planning on building an Ambilight using Hyperion. I have a Pi but use Wetek Play for my main media playback, so I think I'm trying to do the same thing as you. Basically, I want to run Hyperion on the Pi to control the lights, but receive the video data from my Wetek. Is this what you have done? Would be interested to know if you had success in getting it fully working. Thanks!