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Alpha Channels in Media Textures - I know its possible, don't know how though.

As the title says I’m trying to figure out how to use alpha channels or achieve a video mask effect.

I came across this post: https://answers.unrealengine.com/questions/116661/can-45-video-textures-support-alpha-channels.html

But it doesn’t seem to answer any questions. All it does is show the types of files compatible. One of the posters in that link talks about splitting the black and white channels, which I’ve done however they aren’t synced properly, and that seems to be a common problem with that approach. I’ve also attempted to use spritesheets / flipbooks, which give the desired effect, but for trying to use video, it is far too unweildy because of the ridiculous amount of files that you have to use.

I know this sort of thing is possible because Kite and Lightning have done it, or something like it with Senza Pezo like this:https://www.youtube.com/watch?v=lrq0KRbRk1U&t=182

I just can’t seem to figure out how they achieve it. Any help would be much appreciated.

I don’t think it supports any video formats with alpha channels. I think the only solution is to use a second video as a mask. Though, if you have a black and white video or just a single color, you could put the alpha video into one of the other color channels in the same file.

I’ve tried this with a second video mask, but it seems to be just slightly off, and over time it gets progressively worse. I’ll try and experiment a little more with them, maybe I’m just doing it improperly.

I’m pulling my hair out (what’s left of it anyhow) just trying to figure out how it is they accomplished it at Kite and Lightning, since they have video based scenes that are long enough to see the disjoint.

I’d try making a side by side video - effectively halving the horizontal resolution of the video - put your fill on the left and the alpha on the right - then build the mask using crop or something in the material editor.

Totally possible. Iv’e made a top bottom 360* stereoscopic video viewer in ue4 (combined with some other fancy things for a top secret project C:) But here is how i did it for the hud:

Made a black and white version of the video, hooked it up to the opacity mask in a masked material and used the normal video in the emmisive colour (it was unlit)

then to sync them up in blueprint, on event begin play, rewind the two media textured then play them (use a sequencer to do this) and vola, worked like a charm for me. I’m in talks with the guys behind the media texture to hopefully improve it as mentioned in a thread earlier today! Shoul dbe golden soon.

That sounds fantastic. I’ll have to give all of these a try and see. @thegummybear you’ve taken what I’ve done and moved a it just a bit further ill give that a shot as well, and Ill let ya know if I find something awesome.