Video with transparency/alpha in UMG?

Development Programming & Scripting Blueprint
1

Has anyone had any success using videos in UMG which have transparency?

I want to be able to have multiple layers of video playing in a Blueprint Widget, so I need to be able to use transparency/alpha channels.

Anyone got this to work?

Thanks!

2

I figured it out, in case anyone else ever needs to know how to do this:

  1. In the Material Editor, set the Material Domain to ‘User Interface’
  2. Set the Blend Mode to ‘Translucent’
  3. Feed your alpha channel / mask into the Opacity connection on the final material inputs node

Actually pretty easy and self-explanatory in the end!

2 Likes
3

Yep just make sure you export the video with alpha channel properly and you should be good to go, same as creating any other transparent material.

You can do some pretty cool effects with this. The Advanced Materials 1 in the marketplace has a good example of a holographic type display that you can do with any video texture that’s pretty cool

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  1. What is Material Domain, how do I set it to User Interface?

I can’t import any video format that has an alpha channel in it. I’ve tried with .flv, .avi and other, but I’ve realized Unreal doesn’t support videos with alpha channels. So how did you do that?

5

Perhaps use two videos, one with color, and a grayscale one for alpha, and stream them together into the same node?

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i got success using chroma key: Chroma Key Material? - Rendering - Unreal Engine Forums

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i think that’s what you need https://www.fab.com/listings/7cbb0f73-718e-4697-bfaf-3b41e3e24bc1

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multiple layers with transparency is exactly where the built in widget falls apart. you can do one translucent material by hand but stacking them you need proper compositing or you get sorting/ghosting. i ended up using alpha video player from fab Alpha Video Player - Transparent Video UMG Widget & UI Media Component (UE5) | Fab — its a drop in UMG widget that already handles alpha (blend modes for premultiplied vs straight so no glowy edges) and you just layer multiple widgets with different z. png/exr sequence is most reliable, prores 4444 also works if you want a single file — mp4 h264 cant carry alpha btw