Mailing List AE-List@media-motion.tv ? Message #64142
From: Stephen van Vuuren <AE-List@media-motion.tv>
Subject: RE: [AE] VR Tools GPU/CPU VRAM limitations
Date: Fri, 22 Jun 2018 14:37:41 +0000
To: After Effects Mail List <AE-List@media-motion.tv>
> I guess the VRAM requirements for AE are like the ones for Premiere. Quoting 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 with 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 layers 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>
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
> cards as 8+ GB VRAM cards are very expensive.
> * What frame sizes does the VR tools support? We have 5600 x 4200
and
> 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. Quoting 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 × 4320 pixels, requires approximately 2.7 GB.
* Stills from a Canon EOS 5DS, 8688 × 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 required 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 Project Settings.

https://premierepro.net/coolstuff/


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

If the screen resolutions were different, that could explain why this happened. The GPU is also responsible for pushing pixels to the screen. One of my clients failed to do the math, and bought lots of laptops that they planned to use with two 4k monitors. They had to lower the resolution of those monitors 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 seen something like that?


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