How will HDR improve games?
Every little Bit helps!
With the latest marketing lines of HDR consoles and TV's could leave many confused with gaming as it has been using HDR for a very long time, has it not?. And although this is true it is not quite as straight forward as this and much is due to the display panels and how we view images.
High Dynamic Range is the term used to describe more detail across the brightness range which of course includes colour. And even though much of the games industry, 3D modelling and rendering as a whole has adopted this for some time they have to manage this for the intended display type. In short this means that HDR in both PC titles and consoles is only emulated or adjusted, by using gamma correction within the rendering stage and framebuffer. But this article will explain in detail what this means and how it will change. Movies and TV are separate but you can check out that and the new HDR/4K in-depth here or our channel below, but games need to be explained separately.
When materials and objects are created they all have to take into account the display it will be viewed on. With PBR becoming the standard and where HDR really shines and is arguably a necessity for it to work at all. This means that many games now have to create objects, materials and light/darkness within a Linear workflow which corrects or adjusts the luminance for each scene, I covered this in detail with my Metal gear Solid analysis here. This is then corrected or tone mapped so that the colours, whites and blacks all fall within the SDR display. If this did not happen you would have whites that blinded you and became overblown and dark areas with no detail at all.
This is done by adjusting the peak levels within the range of the actual display as in reality a sun glare would make you squint. As this process is usually clamped with a floating point value of 0.0 and 1.0 between darkness and light is also non linear with a short tail on both edge cases of the values. The new Rec.2020 standard with which HDR displays conform within improves this greatly but still not the actual level the eye can perceive and process. All the same it is one of the biggest increases in visual clarity we have experienced in many years with games in particular benefiting greatly from its vastly expanded range and improved gamut.
Due to the lower nit levels of these displays detail cannot be displayed as well as the created base and although more precise it does not match the original target. This means that levels are clamped so that beyond the sRGB or Rec.709 range everything becomes the same no matter how near or far from that it strays. But the adjustment compensates for this and has to form part of your entire pipeline, which the new HDR displays have now changed.
The range is bigger and although the standard can hit 10,000 nit levels we only have consumer displays that can target 1,000 nits at present. This is still a magnitude higher and wider than what SDR standard HD displays have conformed too. It will come as no surprise then that a game will not simply display fine in HDR mode if the rendering has not been changed to do so also. So current games that have this tone mapping and clamping in place will not automatically benefit from this update, they will in fact look the same. But games can have a HDR mode added that could increase the depth and detail of the image, something Crystal Dynamics, Nixxies and Nvidia have done with Rise of The Tomb Raider which you can read about here.
This requires changes to the games rendering and final output to better emulate the detail and depth in the scene. Meaning that the lost detail of white and black before can now be displayed within a larger gamut along with reds, greens and blues. Every shot, material and colour will benefit from this giving much better and more realistic skin tones, vivid colours and even though brighter Bloom areas or darker sections will improve the most this will enhance the entire scene at all times.
New hardware required
Both the XboxOne S & Scorpio support HDR outputs and both Gears of War 4 and Horizon 3 will have full HDR rendering output support on the XboxOne S as I am sure more games will add.UPDATE:- As we have been asked i just want to add that both XboxOne and PS4 can process and output 10-bit colour/30-36bit but only at 1080P, remains to be seen how this will be used in the future. The new PS4 NEO will almost certainly add this function and again it will enhance newer titles that as of October this year all games from 1st or 3rd party will have to add a NEO mode, which means enhanced support to take advantage of the extra hardware boost. So you can expect Horizon, Last Guardian, Battlefield 1 and the sumptuous God Of War and many more to all have HDR enabled rendering options added for the new machine in addition to other enhancements.
Just like moves games will also need to be re-mastered or have this extra rendering option added and I am sure it will be one of the NEO requirements as we approach its actual reveal with its release early in 2017 IMOP. The requirement to maximise and impress the viewer will reside far more on these kinds of improvements over pixel increases. Anyone who has watched or played HDR content can confess that it improves and impresses more than the leap from 1080 to 4K and as such will become another change to game developers workflows having both a SDR and HDR range display mode within their engines.
Examples of how this will benefit games can be seen below on in the video and although these are far from ideal it does demonstrate the loss of detail that still occurs with current methods and display types. Offering up a more precise and wider scope to artists, designers and effects teams will only empower them to create richer, more dynamic and realistic worlds across all supported hardware. The only downside is that original XboxOne and PS4 along with the majority of PC GPU's will miss out on this new display type, but I doubt it will become the lions share of titles over the next few years. Just a welcome benefit and enticing lure to make more owners thing about upgrades or that eventual TV replacement.