From: "Stephen van Vuuren" <AE-List@media-motion.tv>
To: After Effects Mail List <AE-List@media-motion.tv>
Subject: RE: [AE] VR Tools GPU/CPU VRAM limitations
Thread-Topic: [AE] VR Tools GPU/CPU VRAM limitations
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Date: Fri, 22 Jun 2018 14:37:41 +0000
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> I guess the VRAM requirements for AE are like the ones for Premiere. Quot=
ing from page 559 in The Cool Stuff in Premiere Pro:

Interesting. But I doubt it's true since the VR Tools cannot work at all wi=
th GPU acceleration turned off unlike Premiere's implementation. I suspect =
they are using the engine differently.

And if it were frame buffer by layer, in AE it's easy to have 5 or 10 layer=
s in a very simple project vs. Premiere. 50 or more layers is still common =
in AE. You would a graphic card of 50GB+ of VRAM (which don't exist). That =
would be a fatal, dead on arrival design flaw.

-----Original Message-----
From: After Effects Mail List <AE-List@media-motion.tv>=20
Sent: Friday, June 22, 2018 7:37 AM
To: After Effects Mail List <AE-List@media-motion.tv>
Subject: Re: [AE] VR Tools GPU/CPU VRAM limitations

Stephen van Vuuren wrote:

> I can find no useful information on:
> 	* Is there a way to force CPU rendering?
> 	* How much VRAM is required and can you use SLI to split via
multiple=20
> cards as 8+ GB VRAM cards are very expensive.
> 	* What frame sizes does the VR tools support? We have 5600 x 4200
and=20
> 8000 x 8000 - the weird part is simple projects are fine, but bring in
lots of layers, bitmaps and the errors begin.

I guess the VRAM requirements for AE are like the ones for Premiere. Quotin=
g from page 559 in The Cool Stuff in Premiere Pro:

* The approximate amount of GPU memory needed is Width*Height/13107
* An 8K video frame, 8192 =D7 4320 pixels, requires approximately 2.7 GB.
* Stills from a Canon EOS 5DS, 8688 =D7 5792 pixels, require approximately
3.84 GB, so you need a GPU with at least 4 GB video RAM.

8k x 8k requires about 4.9 GB per layer.

This is per layer, so if you blend two layers of that size, double the requ=
ired amount of VRAM to get real-time playback (with GPU-accelerated effects=
 only). When you run out of VRAM, you'll need to render. The rendering will=
 use both the GPU and the CPU, unless you choose Mercury Software Only in P=
roject Settings.

https://premierepro.net/coolstuff/


Brendan Wrote:
> Weirdly, we had other machines with the same graphics card and=20
> everything
else that couldn't.=20

If the screen resolutions were different, that could explain why this happe=
ned. The GPU is also responsible for pushing pixels to the screen. One of m=
y clients failed to do the math, and bought lots of laptops that they plann=
ed to use with two 4k monitors. They had to lower the resolution of those m=
onitors to HD. There wasn't enough VRAM left for AE and Premiere when they =
used the 4k resolution.

I have not been able to find any documentation about how much VRAM is used =
to push pixels to the screen at different screen resolutions. Has anyone se=
en something like that?


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