Avenue 4.5 and Arena 5
A LED processor usually takes a single video input (DVI/HDMI/VGA/composite) and divides this signal over the connected LED walls.
In the case of a single LED screen, setup is relatively simple. The processor takes the top left part of the video signal and shows it on the LED wall. Let's say your LED wall is 384×192 in resolution. The output your processor expects would look something like this:
The processor will only take the top left part from a regular video signal. In this case the regular video signal is 1024×768, but it could be any standard video resolution. It's only interested in the 384×192 pixels in the top left of that signal. The rest it throws away.
You could of course render all your content to this scale before show, but it's much easier to use the Advanced Output.
Create a new setup, and on the Output Transformation stage, you make your single slice 384×192 pixels in size and place it exactly in the top left of your output.
Now switch over to the Input Selection stage, right click the Slice, and hit Match Output Shape. This will place your slice exactly in the same place as it has on the Output Transformation stage. Drag it back to the center, letting the snapping do the hard work for you. Now scale it up until it fills the entire Input Selection stage again, Make sure you hold down both Shift and Alt to scale proportionally from the center!
What you have now is a slice that takes a 2×1 piece of your composition and places it in the top left of your output. This means that you will exactly see that part on your LED wall. By first matching the output shape, you've made sure your input slice has the same aspect ratio as your output shape. This means you probably lose a bit of the top and bottom of your composition, but your circles will still look like circles and not squished eggs.
Now imagine your stage is a bit more complex and looks like this:
The annoying thing is that the 4 screens are positioned like that on the stage, but not in the LED processor. In the LED processor, they might be arranged something like the image below. This is done to minimize the data sent along the cable connecting the LED screens.
(We've included a Photoshop mockup in the bottom right to help you get the idea of how the processor relates to the stage).
Tip! Keep in mind that 4 screens like this are still controlled by a single LED processor. So you only have to send out one signal from your computer's output. The processor divides it over the 4 screens. Only on very complex, high resolution LED stages will you need to use 2 or more processors and thus 2 or more outputs.
First you recreate those four slices in the Output Transformation tab of Resolume's Advanced Output. This way you send the processor the signal that it wants to see. If you're working with a LED supplier who knows what they're doing, they can give you this 'output mapping' before show. All you need to do is fill out the numbers that they provide and name the slices to keep things organized.
Then, on the input, lasso all four slices to select all of them. Then right click and choose Match Output Shape. This will pop the 4 slices into the exact same position and scale they have on the output stage.
Place the 'Center' slice exactly in the center of your comp. Place the other slices around it like they are on the actual stage. Unless you want to break out the tape measure, this usually takes some guesstimating and eyeballing. In the end it's about selling the illusion to the crowd, so it doesn't matter if you're a few pixels off.
Tip! Depending on the stage, there's always a certain trade-off between correctness and pixel count. When you're dealing with a few low pixel pitch LEDs combined with a lot of big crude lowres screens, a perspective correct input map could require your comp to run at 4K or above, In those cases, it might be a good idea to sacrifice a bit of correctness for the sake of still having a decent frame rate.
Once you're satisfied with the layout, lasso all the slices and scale everything up till it fills the canvas again. Shift and Alt are your friends here!
Now whatever you play in your composition will translate perfectly to your LED wall. If you want a DJ's name to only appear on the center wall, all you need is scale it down using the clip properties till it fits. If you want to play content only on the wings, scale it down till it fits on the left wing, and then use the Slide effect at 99.99% opacity to place a copy on the right wing.
Tip! If you're working with LED walls with mixed pixel pitch, you can scale the lower res tiles up more on the Input Selection stage. This will keep their output resolution the same, while taking a larger area of pixels as input. This way, the overall image on the stage will still look perspectively correct.