I might have to retract the “flawless” part of my “sales pitch”. I tried to make it spontaneously work on my work laptop using Fedora and it did in fact, not work. To visually show how it should work, I made a picture with an iPad where it actually does work with my work desktop with 2560x1440 resolution, 60fps. But, it did worked in the past, so I am fairly certain I just suck at using my device. If it would work it appears just as any other capture card…as weird webcam device.
But as said, you need a splitter before the card and then one output into the card. I actually spend a minute to locate a non-black HDMI cable just for you! https://imgur.com/a/BvZDZRJ
Okay, i testet this and its one thing not, rapid, because the interface lags like hell under linux while maxing out my poor AMD 7640u, sure, a laptop CPU but neither darktable not rawtherapee do that. Hard pass for me, an interface that runs with 2fps is just not useable at all.