ClonerAlliance UHD Pro, 4K Video Recorder, HDMI Capture DVR with H.265/H.264 Codec, Cinematic 24fps Recording(Up to 30fps), 4K@60fps Passthrough, Pause/Resume Recording.

I am not recommending this as I have no experience, I am just suggesting a device like this is what you need. Shop around and find your best deal on one though. HDMI Video recorder