VESA DisplayHDR attempts to demystify HDR-capable monitors

Buying a monitor with high dynamic range capability can be confusing. In an effort to make things easier on shoppers, the Video Electronics Standards Association (VESA) is rolling out DisplayHDR, an open and three-tiered set of specifications for HDR quality. The new standard includes test specifications for luminance, color gamut, bit depth, and rise time. The body claims DisplayHDR is the first open HDR specification with a transparent test methodology. The initial version of the spec is focused on LCD panels, but future releases will also measure OLED displays. More than two dozen companies contributed to the development of the DisplayHDR standard, including AMD, Intel, Microsoft, and Nvidia.

The baseline compliance level, DisplayHDR 400, requires true 8-bit image processing, a requirement VESA says only 15% of current PC displays can meet. DisplayHDR 400 also requires compliant displays to offer global dimming, peak luminance of 400 cd/m², full-screen long-duration luminance of 320 cd/m², and coverage of at least 95% of the BT.709 color space. BT.709 is about as wide as the sRGB gamut familiar to many PC users, albeit with a different transfer function or gamma.

The intermediate DisplayHDR 600 specification comes with a more demanding set of specifications. The peak luminance requirement is ratcheted up to 600 cd/m². Sustained bright scenes must be reproduced with at least 350 cd/m² of brightness. Black-to-white luminance response must be achieved in "eight frames" or less. The DisplayHDR 600 color-reproduction spec is also more exacting than the entry-level certification. Compliant monitors must cover 99% of the BT.709 color space and 90% of the DCI-P3 space at a minimum. To achieve high contrast, the extremely dim corner luminance requirement  for DisplayHDR 600—0.10 cd/m²—will require local dimming with today's LCDs, according to VESA. The standards body expects DisplayHDR 600 screens to show up in professional and enthusiast laptops and high-end monitors.

The highest tier of DisplayHDR, DisplayHDR 1000, requires a peak luminance of 1000 cd/m², sustained luminance of at least 600 cd/m², and a corner luminance requirement of 0.05 cd/m², all steps up over DisplayHDR 600 displays. VESA says DisplayHDR 1000 was created with professional and enthusiast content creators in mind. The color space requirement is the same as that of the DisplayHDR 600 standard.

Unfortunately, VESA's DisplayHDR system of standards does not address the issue of multiple HDR content formats, but it at least lays out a simple "good, better, best" system for monitors with HDR capabilities. VESA says it will have a DisplayHDR test tool available for download before the end of the first quarter of 2018. The body says end users will be able to perform tests "without investing in costly lab hardware." A full list of performance criteria is available here.

Comments closed
    • DataMeister
    • 2 years ago

    Wouldn’t the issue of multiple HDR content formats just be handled in software by the video card drivers, as long as the monitor was physically capable?

    I mean this isn’t quite the same as it is over in TV land where the display has it’s own processing system.

      • mtcn77
      • 2 years ago

      The manufacturers are left in the dark on what to do. This designation corrects that since HDR is a different scenario entirely.
      I once watched a video presentation on HDR mobile screens telling the constant variable should not be brightness, but saturation instead for energy efficiency(backlight costs too much power).
      Desktops aren’t subject to the same power constraints, but media won’t follow the same linear “SDR” scheme any more, so the same ‘saturation for brightness’ calibration will still be needed anyway.

    • strangerguy
    • 2 years ago

    A thousand bucks says cheap TVs and phones get actual HDR hardware and support long before PCs even get it.

      • DancinJack
      • 2 years ago

      For sure. Though I doubt too many TVs are gonna be HDR1000 unless they’re crazy expensive (though i’m sure PC monitors bearing the cert would too) and they may not make them at all.

      • EndlessWaves
      • 2 years ago

      AUO has a 27″ 384 dimming zone panel coming and monitors using it are supposed to release in the new year.

      I’d expect great HDR to be primarily focused on devices with a power cable until the technology matures. Judging by the current high end TV implementations it’s often fairly power hungry.

        • brucethemoose
        • 2 years ago

        Local dimming should theoretically reduce power consumption.

    • Chrispy_
    • 2 years ago

    I really likethe attempts to improve black levels!

    0.10cd/m² actually needs a decent VA panel at a minimum. They typically operate with a black level of about 0.15cd/m² on full-brightness, out-of-the-box factory settings and depending on the backlight, some may not necessarily reach 0.10cd/m² whilst also meeting the 350cd/m² required for DisplayHDR 600.

    It’s also going to prove problematic for IPS panels without extremely complex local dimming, too. A typical IPS panel runs at 0.35 – 0.50 cd/m² unflitered, which allows brightness up to around 400cd/m². In order to get rid of corner glow and improve the poor black levels of IPS technology, more expensive panels come with tinted and polarising filters. These have the adverse affect of reducing peak luminance to only 200cd/m² and the black levels are still worse than VA. (Although I can believe that the best, filtered IPS panels can match or even outperform the cheapest VA panels in terms of black level).

    I’d also hope that this HDR standard is the final nail in the coffin for limited-range defaults in some displays. Nvidia drivers are far too eager to switch to the dreaded 16-235 limited range whenever something is connected by an HDMI cable or identifies as an HDTV or HDCP-protected device. There’s no point to limited range anymore. It’s an unwanted relic from the analogue airwave broadcast era, and everything is digital these days – it has been here for 20 years already.

      • exilon
      • 2 years ago

      VA panels have pretty bad vertical black level shift.

      [url<]https://www.rtings.com/monitor/reviews/samsung/chg70-curved-gaming-monitor#comparison_1440[/url<] The haloing is very visible in person. Even VA panels will need local dimming for HDR 600, IMO.

      • brucethemoose
      • 2 years ago

      Phillips figured out a clever alternative to complex local dimming: stick a cheap, unfiltered TN panel between the main IPS one and the backlight.

      You would need a massively bright backlight to compensate, of course, but that should still be cheaper and better looking than local dimming array.

      Unfortunately, that tech will mostly be ignored because it adds a few mm of thickness and increases power consumption. But I hope that nifty little experiment makes its way into a few monitors and TVs, at least.

        • Chrispy_
        • 2 years ago

        Oh, I’d not remembered that, but yeah – that seems like a great idea.

        Also, people who fixate on thinness are idiots. A TV wallmount adds 10x more thickness than a beefy backlight and extra TN layer. For monitors, sacrificing picture quality for aesthetics of the non-viewed side is beyond asinine. Anyway, it’s still possible to make a monitor design look really really sexy without focusing on how thin it is. Plus, thin designs and edgeless designs just end up having an awkward bulge where the ports, speakers, inputs, circuitry have to go, so the effect is ruined anyway, in my opinion.

          • smilingcrow
          • 2 years ago

          Or they make them with slim cases meaning that the USB ports are around the rear which is usually dramatically less easy to access. Who designs this crap!

            • Chrispy_
            • 2 years ago

            The same idiots that make laptops and phones so thin that they don’t have any ports, can’t be upgraded, and are so fragile you’ll break them unless you carry them around in a heavy armoured bag or shell.

        • EndlessWaves
        • 2 years ago

        I bet it kills viewing angles as well.

    • Usacomp2k3
    • 2 years ago

    <Insert xkcd about creating a new standard that is better than all other standards>
    [url<]https://xkcd.com/927/[/url<]

    • EndlessWaves
    • 2 years ago

    For a specification that’s the press release says is to be ‘shared transparently and publicly’ I’m having trouble finding a copy. Anyone know where to find the details?

    My first thought is that this suffers from the same issue as UHD Premium, there’s nothing to encourage good control of brightness. From the overview it seems like it could met by really crude local dimming systems with half a dozen zones that won’t produce anything like the claimed 6000:1 or 20000:1 contrast when displaying actual scenes.

    Plus the HDR400 level is a waste of time, they should either have made it into a mark of a top quality SDR display or dropped it entirely.

      • DancinJack
      • 2 years ago

      First release in the Press Release section of the VESA website. I know it’s an odd place.

      [url<]https://www.vesa.org/featured-articles/vesa-defines-new-standard-to-help-speed-pc-industry-adoption-of%E2%80%A8high-dynamic-range-technology-in-laptop-and-desktop-monitor-displays/[/url<]

      • walken1
      • 2 years ago

      The download link to the full DisplayHDR spec is currently on the main VESA website in the Free Standards section (new item) at [url<]https://www.vesa.org/vesa-standards/[/url<] It should be posted on the DisplayHDR website shortly.

        • EndlessWaves
        • 2 years ago

        Ack, I read the first line of it ‘monitor and display compliance’ and dismissed it. I had to actually search the page for HDR before I realised.

        Thanks for pointing out the obvious 🙂

      • NoOne ButMe
      • 2 years ago

      I remember reading somewhere HDR400 may be meant for laptops, mostly.

      • EndlessWaves
      • 2 years ago

      Having checked the spec, not only is the test pattern easily accomplished by even the most limited of local dimming systems but they don’t even require that the input white values to be correctly reproduced!

      So like several TVs aleady do, we’ll see screens meeting this spec by dimming the highlights instead of actually having HDR contrast.

      This seems like a real missed opportunity.

    • EndlessWaves
    • 2 years ago

    HDR400 seems to require 10-bit processing and an 8-bit LCD panel judging by the table on the performance criteria page of their site.

    • mtcn77
    • 2 years ago

    Too complex; blurring the lines…
    – How about 400(TN), 600(VA), 1000(OLED)?

      • deruberhanyok
      • 2 years ago

      really missing the point of the standards they’re trying to apply. Not all VA panels are created equal, for instance.

      The idea here is that you have a set level of color capabilities you can expect with whatever type of panel is in use, making it somewhat less relevant – who cares if it is VA or IPS if it has the local dimming, etc, required to be “HDR600” compliant?

      (And anyone who DOES care wouldn’t likely be paying attention to the spec anyways).

        • mtcn77
        • 2 years ago

        Attribute specifics would still hold, as in ‘600(VA)’ > just generic ‘VA’. Otherwise, just how do you standardise the new standards?
        [quote<]- making it somewhat [i<]less[/i<] relevant[/quote<] Circumventing the decisions. Just... more... bloatware!

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