I assume you have the video inputs enabled, etc in catalyst?
Yes, I know the minimum, it finally works hdmi or sdi. The problem was to find the right input format. Oups.
And it seems a GoPro can't give me the right format.
Yes, its not a scan converter so you would have to hit one of the resolutions that it understands. A http://www.decimator.com in line would be a cost effective way to fix that.