Okay, Scarlet shoots 4K video (as do EPIC and ONE). What is needed to show it?

Let's work backward from the display. From what I've heard, some prototype TVs are built with four HDMI inputs. I've heard of a 4K TV model that accepts dual DVI (or was it Display Port?)

What will the connection be when we have 4K TVs in our homes? Certainly, it will be a one wire connection.

From a computer, I believe that there are dual DVI and/or dual Display Port cards, but I'm not aware of any that have quad HDMI. If that's what the display accepts, that's what I'd need to support. I guess you could genlock multiple high-end cards.

Next, there is the source device. For editing, it's a computer, possibly with a RED Rocket. But what about just playback? A RED Ray would be perfect. Burn a disc, put it in a RED Ray, connect four HDMIs. But that's not out yet. Are there any other options out there? (Aside from a full boat digital cinema projector system.)

I'm curious to know what is actually being used out there...

Only specialist technology is currently available or 4K display and playback. Most people shooting RED don't deliver 4K, they deliver HD, so only need tomonitor in HD. Monitoring of 4K will become easier as more monitors hit the market, for desktop solutions the connection is likely to be HDMI or Thunderbolt, or a form of HD-SDI style connction (although current specs require multiple connectors for 4K).

If you have enough money, you can buy projects that resolve out to 4k and you could play it back at full res. The final delivery format will, most likely, be in 1080p as any format higher will not be viable for playback on normal devices.

When it comes to 4K playback in the home? Fiber, thats my opinion. Obviously that market has not developed yet and I am sure someone will develop a next generation HDMI or other proprietary port for sale as well.