I use Blackmagic Decklink quad for my output. In the settings under external I have ticked external renderer and selected, under the device option, my preferred output channel on the Decklink and it works fine except for severe lagging. It lags about 1 minute meaning I can't use that for live shows but more for replays and displaying information and the like. Having said that it could also be due to the distance between the control room and the external display. Mine is about 50m away.

Roku gadgets are easy to deploy, have very good image quality, and very low cost, but I haven't had luck yet getting <20 seconds delay (Silverlight streaming may help but haven't had time yet to tinker). Teradek Cubes can cut the delay to ~1 second, but are expensive and tricky to set up. Both would work over TCP/IP, making distance less of an issue (you mention a stadium, so max cable lengths for video protocols could be an issue).

For streaming to drive the displays, you could create a local Wowza server, or create a Wowza server in the cloud - Azure makes it very easy to build one, and Wowza offers reasonable monthly terms for the software.

You can run 3 displays on that graphics card. I also meant to ask

1. Are the stadium monitors showing SD or HD video?
2. How is the HD signal distributed to all the monitors in the stadium? I am wondering if the stadium is using Cat5 or SDI for the video signal?
3. How close is your streaming PC to the video input of the Stadium HD Monitor Input system?

If you are using an SDI splitter then using something like a Blackmagic Decklink Monitor would be good to output the SDI signal and run it straight to your stadium monitor system.

Tim

Slaver,
The first thing is to make sure all 3 monitors show up in windows properly. With 3 monitors hooked up, confirm you are utilizing all three monitors. Use the "Identify" function in your display settings to see the number assigned to each monitor. Note which number the HDMI monitor is.

Now in vMix.
1. Click on Settings in top right corner. You are now in the "Display" section
2. Under green DISPLAY 1 button in middle, click on the drop down menu to the right of word "Display".
3. Select the number that was displayed on the HDMI monitor in first step above. Then click on OK.
4. Add camera input or video input to vMix and make sure it is showing in OUTPUT window.
5. Click on FULLSCREEN dropdown menu located at top-center of vMix screen > Put mouse over DISPLAY1
6. Select what you want shown on DISPLAY1. You can map the Output, Preview, Multiview, or any active Input to the DISPLAY1. If you are wanting to show the vMix output on all the stadium monitors, then you will select OUTPUT.
7. After you have made your mapping select, click on the FULLSCREEN button itself. The button will turn green meaning the FULLSCREEN option is now on. IF you mapped "Output" in the previous step, then you now see the vMix Output on the HDMI Monitor.
8. Now that you know it is working, unplug the HDMI monitor and run and an HDMI cable from your video card to the HDMI switch input (which you said is about 12 meters from the PC). Here is a link to a 50' HDMI cable on Amazon for $14. http://amzn.com/B00RYRJYDG.

The higher versions of vMix will support 2 FULLSCREEN outputs where the basic versions will only support 1. But for what you are doing it sounds like you only need 1.

I hope this is clear and easy to understand.

Tim