Multi-camera setup through thunderbolt - how can I do this?

Hi there!

I've been trying to solve this problem for a live setup with cameras, but can't find the right answers...

This is what I need the live setup to do:

I'm building up a show with live cameras + pre-recorded videos which will be launched via MIDI or SMPTE through Resolume or Qlab (I'm still trying to understand which of them are more safe from errors). At some point, I'll need to launch 6 layers of video simultaneously, 3 of them pre-recorded and 3 LIVE from the cameras onstage. All of this will have to be totally automatic through mapping being received via MIDI or SMPTE. What I'm failing to understand is the best video device to capture the live cameras through HDMI and into the mac thunderbolt. I don't want this to be a bulky system, so I need ONE video device that can receive up to 4 cameras via HDMI and that can be recognized by Resolume or Qlab individually.

Does anyone have a suggestion regarding the video device that I should use for this to work?

Thank you!

I would think that the just announced "DeckLink Quad HDMI Recorder" inside an external thunderbolt case such as the ones from sonnet http://www.sonnettech.com/product/thunderbolt/ would do the trick.
Worth a consideration would be that HDMI limits the distance between said card and your cameras to a few meters before becoming unreliable, so you might want to look into the SDI version of this DeckLink Quad card if you need longer cable runs (and throw in a few HDMI to SDI Mini or Micro Converters on the camera side).

And you would probably need a rather strong Mac to handle it. We used our DeckLink Quad card with a maxed out 15inch 2015 Macbook Pro to record 4 streams of 1080i50 as ProRes422 (it handled it fine, but would struggle as soon as we would step up to 1080p50 already).

Cheers,
Daniel

Would an ATEM TELEVISION STUDIO do the trick?