Lightact & UE4 integration

Copied from the old Lightact Answerhub.


Great work with the Lightact/UE4 integration. Can the Spout plug-in support alpha to/from UE4? We want to render just a 3D object and place the object on top of a live video feed outside UE4 without resorting to hacks like keying out the object.

Also, do you have any plans to implement Blackmagic Decklink support?


Johan Folke


Not at the moment. Technically it should be possible, but while trying to do that just now we discovered a minor bug, which messes up the alpha. Hopefully, we’ll be able to fix this for 3.0.6.

Regarding Blackmagic Decklink support: it might actually work already depending on how Blackmagic drivers are created. We’ve developed our Video Capture device (in the Devices window) based on Datapath’s capture card, which represents itself to the system as a video stream. The same way as all USB video cams represent themselves for example. I would say it is likely that our video capture reader would detect Blackmagic’s cards as well.

Do you have any means to test it? I would be more than interested to find out as well.



Copied from the old Lightact Answerhub.

Cool, alpha support could really open up some exciting possibilities.

We’re working on a Virtual Studio solution using UE4 and I think we could use Lightact to overcome some of the weaknesses with handling video in UE4.

I’m sure Decklink won’t work unless you implement specific support for it. They had some general windows drivers available before, but it’s pretty much abandoned now. Fortunately, the Decklink SDK is freely available and the cheapest Decklink card is just like $145, so it should be quite easy to implement. We’ve been working with a developer to implement a custom ingest application using Decklink and I can put you in contact with him if you want to outsource the work to someone who is used to working with the SDK. Still, I think basic capture and playback should be pretty trivial to implement and we could certainly help you test it in a broadcast environment.

Alpha support for Spout from Unreal Engine has been fixed and is included in v3.1.0.

There is also a video tutorial.