Render to an Nvidia Quadro SDI with key

Does UE4 outputs the Alpha Channel, for example with a Quadro SDI ?
This is for broadcast purposes…


No, there’s no alpha channel. It might be possible to combine things within UE4 instead of trying to plug UE4 output into something else though.

But is it possible to render the buffer to another output/screen? You should be able to make a key with all the available outputs.

You might be able to do something like output a depth buffer to a second screen and then use that with the rendered image to composite things, but you’re going to be limited by how you might fill up the output image with information besides the rendered image.

ok, but i’m kind of confused. I’m judging here if we can jump in UE to do some broadcast works.
But we need a key and, as far as i know these nvidia cards can output the ARGB directly from the GPU so do UE output the full ARGB ?

Most people on this forum won’t have the equipment to test this, so the easiest way to find out is probably to just try it yourself.

I’d be surprised if it turns out it is supported as it is quite a niche feature, but you never know. If it isn’t you also have the full source code. It might take some digging to find where to implement it, but it doesn’t sound like something that is particularly hard to adjust.

Did you ever find out if this is possible with UE 4? I know for sure it was possible with UE3 - but it might have required custom coding

I moved on with some other stuff but now i really want to get back onto this.

Do someone have a starting point on this (even if it was for UE3) ?

Hi, i’ve been doing some broadcast work with the engine and have been looking into this. The closest I came to it is making a post process material which makes a side by side key and fill based on one of the many gbuffers available. This means you’d have to do some fiddling in a DVE or avid in my case. I had an idea of creating a double wide game window like 3840x1080 and using the same material to pull out the key and fill.