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Graphics cards manufacturers like Nvidia and AMD have gone to great pains recently to point out that to experience Virtual Reality with a VR headset properly, you need a GPU capable of pushing at least a steady 90 FPS per eye, or a total of at least 180 FPS for both eyes, and at high resolutions to boot. This of course requires the purchase of the latest, greatest high-end GPUs made by these manufacturers, alongside the money you are already plonking down for your new VR headset and a good, fast gaming-class PC.
This raises an interesting question: virtually every LCD/LED TV manufactured in the last 5 — 6 years has a "Realtime Motion Compensation" feature built in. This is the not-so-new-at-all technique of taking, say, a football match broadcast live at 30 FPS or Hz, and algorithmically generating extra in-between frames in realtime, thus giving you a hypersmooth 200 — 400 FPS/Hz image on the TV set, with no visible stutter or strobing whatsoever. This technology is not new. It is cheap enough to include in virtually every TV set at every price level (thus the hardware that performs the realtime motion compensating cannot cost more than a few dollars in total). And the technique should, in theory, work just fine with the output of a GPU trying to drive a VR headset.
Now suppose you have a entry level or mid-range GPU capable of pushing only 40 — 60 FPS in a VR application (or a measly 20 — 30 FPS per eye, making for a truly terrible VR experience). You could, in theory add some cheap Motion Compensation circuitry to that GPU and get 100 — 200 FPS or more per eye. Heck, you might even be able to program a few GPU cores to run the motion compensating as a realtime GPU shader as the rest of the GPU is rendering a game or VR experience.
So my question: Why don't GPUs for VR use Realtime Motion Compensation techniques to increase the FPS pushed into the VR headset? Would this not make far more financial sense for the average VR user than having to buy a monstrously powerful GPU to experience VR at all?
(Score: 0) by Anonymous Coward on Thursday July 14 2016, @04:15PM
You want 90 FPS per eye, is not to me, total 180FPS, but still 90FPS. Since each eye is only using 1/2 the screen. Why 2 screens, one for each eye, where Goggle Cardboard showed you can do it on 1. Even if you did have two screen, like a google glass for each eye, split the signal 1/2 for each eye.
So 1/2 1920 x 1080 would be 960 x 1080 for each eye.
(Score: 2, Informative) by fishybell on Thursday July 14 2016, @04:38PM
It's not that they render on two screens (I'm fairly certain none do), it's that they have to render two scenes. The different scene seen in each eye is exactly as complicated to render on the same screen as it would be to render on two different screens. The extra scene can also be more complicated than just rendering the same scene with twice the resolution.
(Score: 2) by takyon on Thursday July 14 2016, @11:08PM
That's just not true anymore. For example:
http://wccftech.com/pc-vrps-vr-gap-bigger-nvidias-pascal/ [wccftech.com]
There are other such techniques that are being used by both AMD and Nvidia to bring down the amount of computation needed to do VR.
And, yes, some or most of the VR devices have two literal screens inside them. This is most obvious with stuff like StarVR, where the screens are angled to provide a wide field of view.
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(Score: 2) by Tork on Friday July 15 2016, @12:07AM
The different scene seen in each eye is exactly as complicated to render on the same screen as it would be to render on two different screens.
Weeeeelllll.... sort of. I'm gonna be a little pedantic here. You are correct that they have to render two screens, but I want to nitpick the statement that each eye is exactly as complicated to render. You are right that it will have roughly the same number of vertices, polygons, texels to fill, etc. But there is one key difference: The deformation of the models, the placement of effects like particles, placement of the characters, etc, still only need to be calculated once. In other words, a very significant portion of the work does not actually need to be done twice. Just reuse that data and slide the camera over and render one more time. In practical terms, what I'm saying is that you could have a game that renders at exactly 60.000 frames per second, but a stereo render of it may not actually be exactly half that. It could end up being 49.234 fps.
It all really depends on what parts of the game actually generate significant latency.
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(Score: 0) by Anonymous Coward on Thursday July 14 2016, @05:03PM
From a signal bandwidth point of view, there is no difference between doubling the image size or doubling the framerate.