Pimax 8K using full resolution


#1

I’m a VR artist also working with stereoscopic photography. I was wondering if you guys think it might be possible to make use of the FULL resolution of the 8K screen when only showing non-interactive photo content without positional tracking, and no 360 content. Meaning I’d like to avoid the upscaling in this case.
This would improve my presentation at galleries and museums tremendously.

Thanks for your help
Felix


#2

irrespective of the kind of content, you would need an 8kX for that.

What i will say is that if the 8k works as planned it will be the highest quality vr presentation method that will exist for some time commercially, with the lowest level of screen door effect.


#3

My hope for the future is that there will be a Pimax 8KX+ version, which has a bypassible scaler chip and can run native (4K), 1440p, and 1080p resolutions. I think a product like that would be very successful commercially.


#4

This isn’t exactly clear to me. Let’s think about the Pimax in this case as ‘just’ two 4k screens. A displayport 1.4 cable is able to transmit 8k content. Why shouldn’t it be possible then to transmit static content in this resolution? Without the need to do heavy VR processing, 80hz and tracking?

I understand the 8KX needs two cables because it’s attached to two GTX, since you need twice the GPU power to achieve INTERACTIVE content.

Can you follow? I’d like to maybe even bypass the ‘VR environment’ if needed, to just use those screens as ‘simple screens’.


#5

Nod . to explain. Whether the content hitting the headset is a complex 3d scene being rendered, or a 360 panorama, the number of pixels being sent to the headset is the same. There is a tremendous difference in the work required to generate each pixel in these two cases, but the same volume of data , that is, 2d renders for each eye, need to be sent to headset. The volume of data being sent to the headset is also not a question of size 2 x 4k(actually i think much smaller than this and upscaled on headset end), but of framerate. The cable might be able to handle it. but can it handle it at 80- 90 fps. Lastly, and this is where rubber meets the road, the absolute bottleneck in practical reality is chip inside the unit. That chip is already unstable above 80 hz and cannot be bypassed.


#6

Ah I see. Thanks @destraudo for clearing that up. I just figured the 8K would be using the same chip as the 8KX. And since the 8K will display all pixels in the end anyway, I thought one might bypass the upscaling for static content.


#7

@destraudo well said! That’s an excellent description of data transfer bandwidth.

@TheSwanCollective, all three units (5K, 8K, and 8KX) use SOME of the same chips.

There’s a chip that handles the DisplayPort 1.4 signal from the GPU (actually, the 8KX has 2 of those) and the 8K also has a scaler chip, which stretches the 1440p input resolution to the 4K native LCD resolution, but the other 2 headsets do not include that chip.

It’s not 100% clear, but it appears that the scaler chip is the source of the 80 Hz refresh limit for the 8K unit. The 5K doesn’t have that chip, so it can run at 90 Hz. It’s likely that the 8KX will also be able to run at 90 Hz, since it doesn’t have a scaler chip either.


#8

Just to add the clarification to what @destraudo wrote. The HMD uses (supposedly) low latency LCD panels, which means, it needs to be refreshed at certain refresh rate to “keep the image”. Unless you have e-ink tech, or some buffered “always-on” display you need to feed the panel regardless the type of the picture, whether it is static photography, or fast paced action game.

So far, Pimax has not confirmed that scaler chip is the source of the problem. It may equally be 8K panel itself, which cannot handle 90Hz refresh. 5K unit uses different panels (2560x1440).


#9

It seems likely that the issue is with the scalar since the 5k will have identical resolution being sent to it and is so far at least sounding like it is 90hz. It could in theory also be the screens but the scalar is the more likely component since they aren’t really designed for bandwidths in excess of the usual standards. My guess is the hope with achieving better is based on trying to clean up the power so it can be overclocked since they only need about 10-15% more out of it.


#10

Just to clarify, when I said panels, I meant the panel and its interface chip (MIPI). In simple visualization:

5K:
DP bridge --> MIPI --> Panel (both, MIPI and Panel are “the display”)

8K:
DP bridge -->MIPI --> Scaler --> MIPI --> Panel

Now, MIPI (at panel) runs different pclk for 5K and 8K, 8K should be more than twice faster than 5K, and my suggestion was that it could also be this pclk which is out of spec/unstable at 8K panel interface.


#11

The 8k panel was confirmed by pimax that it can do 90hz & is in use in another project using Qualcomm.

Now it might be the scaler but on the otherhand there might be an instability that isn’t affecting the 5k input but might also be amplified when upscaled. In any event its all speculation as to why the 8k is experiencing this. All theories are possible.