Identify 19-pin connector that looks like USB micro
HDMI Type D, aka Micro HDMI. Has the same signal set as regular HDMI. There are adapters and cables to go to regular HDMI that might make your life easier.

That said, they probably repurposed the pinout to their own use, so you'll need to reverse engineer that. But it'd be really lame if they didn't re-use the diff pairs.