Video Player Camera Near/Far Plane more than one

xzodia · December 21, 2022, 11:56am

I want to render multiple cameras to the screen each with their own video player rendering to their Near or Far plane.
However, when I tried to do this all the cameras render the same video.
Is this a bug? Is there anyway to make this work?
My main reason for wanting to take this approach is that I understand it is the most performant option.

marc_tanenbaum · December 21, 2022, 2:59pm

Can you post some screenshots of your setup (hierarchy/inspectors)? I’m not sure I’m clear on what exactly you’re trying to do.

xzodia · December 21, 2022, 3:40pm

For demo purposes below, the screen in split into 4 sections, rendering 2 cameras in the BL and TR corners.

Expected Result:

Actual Result:

xzodia · December 21, 2022, 3:41pm

Video player setup

marc_tanenbaum · December 21, 2022, 4:12pm

Let me do some checking and I’ll see if there’s a sensible answer.

marc_tanenbaum · December 21, 2022, 7:33pm

Hey @xzodia

I’ve asked the Video team and gotten some useful info.

It looks like you’ve stumbled on a long-standing bug that’s only recently been addressed in 2023.1.0a20, and the fix hasn’t been back-ported, at least not yet.

The problem this fixes is that the same material instance used to perform the compositing directly into the camera was shared among all VideoPlayer instances. This was leading to a situation where the last VideoPlayer that writes into the shader will “win”, overwriting the content provided by previous VideoPlayers that rendered during the same iteration. This is now fixed and each VideoPlayer instance has its own compositing material instance.

However, the more fundamental limitation of this approach remains, and this is something that’s been on the “to-do list” forever: the compositing order is undefined. There is no way to control which VideoPlayer will go first, so the end result is entirely up to some internal execution order details (like which VideoPlayer becomes enabled first, and so on). I wouldn’t recommend depending on this.

The better approach is to use a canvas renderer (this is what the VideoPlayer uses for rendering into cameras anyways). So attaching VideoPlayer.texture directly to a Canvas RawImage will provide essentially the same performance, and let one control the Z order as well as other rendering parameters.

Hope this helps!