Hello
Before I start I have to say Im from Germany so if you dont understand anything because Im bad at english then please let me know! 
I want to build my own Ambilight system. I have the WS2801 LED Stripe + HDMI to AV Converter + Logilink AV to USB Adapter + RaspberryPi. Until now I tested every object (except the logilink Adapter (VG0001B - I did not install the software because 1. I dont have a CD drive for RasPi and 2. I werent told to)) and as far as I know everything seems to work. When I use HyperCon I can control the lights of my LED Stripe. It works great. When I activate and Update my Configuration by adding the external grabber, nothing works. Not even the Colorful start (if you know what I mean). I didnt change anything else. I even tried deactivating the internal grabber but nothing works. Only if I deactivate the external Grabber again and update the file, then I can Control the lights.
P.S.: I use LibreELEC
P.P.S.: I upload my hypercon file here. Its the one where external and internal grabber are activated.