PS4 Pro, checkerboard rendering

Discussion in 'Console Technology' started by Scott_Arm, Sep 9, 2016.

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  1. Scott_Arm

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    Apparently there is a hardware component to the solution. Without details to go by, here are some 4k screens of Horizon Zero Dawn that were released by Sony.

    What do you guys think?

    http://www.eurogamer.net/articles/2016-09-08-horizon-zero-dawn-4k-screenshots

    One of the sample shots:
    [​IMG]


    What is checkerboard rendering? The basic idea is, you render half the pixels in a checkerboard pattern and then reconstruct the rest. For instance, you could render the red pixels in this 2x2 grid pattern and reconstruct the green pixels. This is suggested in Valve's checkboard method in a presentation on rendering for VR. It is not yet known if this is what is suggested by Sony for PS4 Pro.

    [​IMG]
    image credits to @HTupolev


    There are a few known solutions for this. Rainbow Six Siege does a version of this. I believe the checkerboard pattern is individual pixels instead of 2x2 pixel groups. It uses motion vectors to reconstruct the green pixels from a previous frame of data. For a 4k output it would render at 1080p with 2xMSAA to get half the samples of 4k. See checkerboard rendering in this slide show. The final resolve is very complex and would be hard to implement as an easy solution for developers to turn on/off.
    http://www.gdcvault.com/play/1022990/Rendering-Rainbow-Six-Siege

    The other method I've seen linked by Digital Foundry was suggested by Valve for VR. It has 2x2 pixel groups and it interpolates the missing "green" pixels by average neighbouring pixels with weighted values. It would probably cause some blur, on top of whatever other artifacts that type of interpolation would suggest. The information begins at slide 21. http://alex.vlachos.com/graphics/Alex_Vlachos_Advanced_VR_Rendering_Performance_GDC2016.pdf

    @Globalisateur Linked a Sony patent that describes "uprendering" multimedia content. It appears to only require the current final frame buffer as a reference, and then creates a number of sub-pixel shifted copies to reconstruct a final "uprendered" image. The example in the document creates a 2x2 matrix out of each pixel with a 0.5 shift right, a 0.5 shift down and a 0.5 shift diagonal. That is my understanding. Good candidate for hardware. Does not seem to match well with "checkerboard" rendering or Jonathan Blow's vague (because of NDA) comments about PS4 Pro. May be a good starting point.
    https://patents.google.com/patent/US20160005344A1/en
     
    #1 Scott_Arm, Sep 9, 2016
    Last edited: Sep 12, 2016
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  2. Scott_Arm

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    All I really notice is some sawtooth pattern on the edges and what looks like little dots along high contrast edges. I think it might be hard to see in motion unless it shimmers. Don't have native 4k as a reference, so it would be hard to judge if some high-frequency detail in textures has been lost.
     
  3. DSoup

    DSoup meh
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    Secret hardware you say? :runaway:
     
  4. Cyan

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    probably, a hidden upscaler performing it so the developers don't need to program complex algorithms
     
  5. Dictator

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    I get the impression that this is just an upscaler with a different method than linear / bi-linear / bicubic. The real interesting part about how PS4pro games are output at 4K would be done by the engine itself on a per-game basis... and not by a dedicated hardware block.
     
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  6. ultragpu

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    Is the base native buffer at 1800p as I've been hearing lately?
     
  7. BRiT

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    What is 1800p? Its hard to keep track when there are different versions of each res and sometimes the ####p designator is based only on the vertical resolution, so is it ultrawide or normal 16:9 ratio.
     
  8. mpg1

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    the 900p of 4K.
     
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  9. Rurouni

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    he probably wanted to write 1080p
     
  10. ultragpu

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    Sorry I should specify it's 3200 x 1800 res.
     
  11. BRiT

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    Thanks. So it's 4x that of 900p (1600 x 900).

    That 1800p still seems to be quite impressive to me as a "compromised" resolution as some might call it. Yes, native 4K (3840 x 2160) resolution is higher and better but requires vastly more resources. Some are quite happy with 1440p (2560 x 1440) resolutions. Granted, this doesn't take into account any possible differences between HDR and non-HDR or bitrate or refresh that might be in the mix, but I'm assuming all those items being equal and it's only resolution differences.
     
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  12. Clukos

    Clukos Bloodborne 2 when?
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    Even 1440p can offer pristine IQ in comparison to 1080p. AC Unity at 1440p maxed

    [​IMG]

    It'd be great if they patched it for the pro, i'm thinking the cpu oc would help significantly with keeping a steady 30 fps and the game would be a good showcase for what the pro is capable of in comparison to the base ps4 (which runs at 900p and doesn't do the game justice). But they probably won't bother :p
     
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  13. djskribbles

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    Don't think so. Richard said the results were better than 1440p native.
     
    #13 djskribbles, Sep 10, 2016
    Last edited: Sep 10, 2016
  14. bgroovy

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    There is no "native" base with checkerboard rendering. 1800p was the lower limit for a final reconstructed frame Sony asked devs to contact the if they could not reach with Neo. You probably would see that more with 60fps games that are 900p on the base PS4.
     
  15. Globalisateur

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    It could be interesting to update your OP with this image (credits to @HTupolev):

    Render the red pixels, reconstruct the green pixels.

    [​IMG]
     
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  16. mpg1

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    So there is supposed hardware in PS4 Pro that helps with this checkerboard rendering and doesn't cost anything to developers? If so does that mean the extra power of PS4 Pro can be put towards max details and then just "checkerboard rendered" to 1800p/4K? Or am I really simplifying it?
     
  17. Jay

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    http://wccftech.com/blow-checkerboard-rendering-ps4pro-isnt-completely-free-might-better-uses-power/

     
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  18. Clukos

    Clukos Bloodborne 2 when?
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    As i understand it you still have to hit 2x900p for 1800p (which is 4x900p) and 2x1080p for 4k (which is 4x1080p) so it's not free. What is happening on h/w after you hit 2x900p/2x1080p should be free. Under most circumstances the Ps4 pro should be able to handle ps4 900p titles at 1800p and 1080p titles at 4k w/ checkerboard, given the h/w bump.
     
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  19. BRiT

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    I'm not so sure unless we start doing the maths. Hitting 2x900p/2x1080p will take at least 4x memory bandwidth for both, which is an absolute min of 4x of 900p, right? That area was barely upgraded, right? It should struggle if rendering is bandwidth limited.

    I dont know if the hw bump was bumped enough in the right areas.
     
  20. Clukos

    Clukos Bloodborne 2 when?
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    I'm assuming they improved on memory compression to make this possible and the pro shouldn't require 4x memory bandwidth (176 gb/s x 4 = 704 gb/s, a number the pascal titan x is not even close to) to hit something just above 1440p (2x1080p = 4.1 million rendered pixels vs 3.6m for 1440p).
     
    #20 Clukos, Sep 11, 2016
    Last edited: Sep 11, 2016
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