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Tomdarkness | 5 years ago

8k seems... optimistic. The PPI of such a display would be off the charts. Not to mention the kind of hardware required to run such a device. The NVIDIA RTX 3090 can barely run a 3D 8k game at 30fps, let alone in 3D for VR. What would you even connect such a device with? Displayport and HDMI wouldn't support two 8k streams.

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riggsdk|5 years ago

Since they do mention eye-tracking they can heavily exploit foveated rendering which will make the resolution extremely high at the exact point where your eyes are looking and much lower in the outer regions of your vision. This is practically unnoticeable (if done right) and allows for much more interesting performance optimizations. Full 2x8K in 90Hz is impossible otherwise.

jayd16|5 years ago

Part of the problem with foveation is its pretty noticeable and mildly annoying for not a huge gain.

leecb|5 years ago

>Apple will liberally use an already-known VR technique that involves using eye-tracking to render objects in the user's periphery at a lower fidelity than what the user is focusing on.

This seems to be describing foveated rendering, which is reducing the image quality in your peripheral vision, because you are less likely to notice it there. It requires tracking where the eye to so you know what part of the screen the eye is looking at.

The RTX 3090 is likely rendering the whole 8k screen at a consistent quality level, whereas foveated rendering would mean that only the part of the display that the eye is actually focused on would be rendered at full quality. If Apple could pull off the tracking well enough (accurately, with low latency), they could probably save a lot of GPU power by lowering render quality outside of what you're looking at.

https://en.wikipedia.org/wiki/Foveated_rendering

jiggawatts|5 years ago

a) Deep-learning super sampling (DLSS) allows upscaling to 8K at a low cost.

b) VR uses variable rate shading because we have a lower visual acuity in our peripheral vision.

c) VR rendering typically "shares" a significant amount of the work between the two viewports. E.g.: one set of "commands" are rendered simultaneously into two buffers with different view transforms. Textures and meshes are cached once and rendered twice, so the bandwidth requirements aren't actually doubled.

d) Display stream compression (DSC) and similar technologies would work well for VR because the viewport is always in motion with a high refresh rate. One could even imagine sending a H.265 compressed stream wirelessly at a mere gigabit, which is fantastically high bitrate video but well within current WiFi capabilities.

e) There will be future developments as well, we're not stuck with current technology. Keep in mind that current era flagship GPUs are manufactured on silicon processes that are about 3 generations old! By the time this VR kit hits the mainstream market, GPUs could be manufactured on a 3 nm TSMC process and easily put out 90fps in 8K resolution.

shock-value|5 years ago

Regarding (d), if you have a Quest / Quest 2, there is no need to merely imagine; this is how WiFi + Virtual Desktop works now for PCVR connectivity, and it’s excellent. (Not sure if it tops out at a gigabit but it’s much more than enough for a great experience at 4K of the Quest 2.)

riggsdk|5 years ago

Especially if Apple keeps pushing their custom GPU's (which are already at 3nm). The current M1 GPU is somewhere between a GTX 1050 and a 1070 - so still a few generations old. With a bit more focus on the GPU part (and use a bit more power) they might be able to pull it off.

banana_giraffe|5 years ago

The article mentions use of something like a M1 processor, so I'd assume this is something like the Oculus Quest where the rendering is done on the VR headset itself.

It'd also explain the price tag, if you have to buy both a high quality display and a speedy GPU that's been glued together.

jayd16|5 years ago

I wonder if the bulk of the resolution is to handle this pass through video in a fixed pipeline. Programmable rendering could be at a much lower resolution and scaled up in hardware.

brokencode|5 years ago

Like mentioned in the article, they would only be rendering what’s directly in the clearest part of the eye at full resolution, so the idea of actually needing to transmit two full 8k streams is not right.

Also, it sounds like this would be more of an all-in-one device, where it’d handle the rendering instead of connecting to a separate computer, so the rendering performance is more likely to be the limitation than any kind of transmission limitations anyways.

pezezin|5 years ago

If you want the latest AAA game in ultra quality, then of course no GPU can run it at 8k. But I'm pretty sure a RTX 3090 can run older games at 8k.

barnabee|5 years ago

I suspect an RTX 3090 could run many Oculus Quest 2 games at 8k.