@emtv

I just ran a few tests with my USB3 BM intensity shuttle.

Using a HDMI output from a mac mini (set to 30p and later 60i)
I am able to capture at the specified resolution from Live Capture, and have the HDMI output work as a Monitor feed (I had issues with some of my displays not supporting 60i)
I am able to output my stage to the Device HDMI output.

I can not:
- switch the output between being a Stage Output, and an Input monitor (requires stopping live capture, and toggling the checkbox on Stage Setup. So can be done manually)

The issue of the device being added on newlines, and with the offline suffix, I believe to be an issue that was fixed some time ago. (I remember testing this).
I would recommend updating your version of Isadora. (you list Isadora 3.0.7)

NOTE: your computer spec is very similar to my own, so I don't believe that will be a factor.

@mark_m ah ok...thanks for the warning

Best,

I recently bought a Datapath VisionLC HD2 HDMI capture card and I wanted to share my success.

Above you can see it capturing an output from isadora running at 1920*1080 and up-scaling it to 3840*2160 (see below). I have since read it can capture a single HDMI at full 4k - which I will try one day.

The hardware cost £435 which is pretty cool as this can capture DUAL HDMI inputs. So its almost £200 a channel input capture.

Frame delay is minimal but the quality is amazing. 

It's also: 

PCI Express Gen 2 x 4 low profile

And it is indeed low profile! I was very tight on space.

I have done now hardcore testing yet but it works and I will keep you posted on my research.