VESA have today announced some improvements to their DisplayHDR standards, tightening up some of the criteria for their certification scheme as well as introducing a new HDR 1400 tier. The new HDR 1400 tier also provides further enhancements to the scheme at the top end including enhanced peak brightness capability to account for modern backlight options.
Article updated 10/9/19 with some corrections and clarification around the new certification criteria
Tightening up of HDR certifications
VESA say in their press release that this has been done to “address recent advances in HDR technology”, but despite how the press release is worded, the changes are not as significant as we first thought unfortunately.
“Since we launched the DisplayHDR compliance test specification nearly two years ago, display manufacturers have made excellent progress in refining the performance and capabilities of their HDR displays beyond what was originally defined in the standard. To represent the gains that the display ecosystem has made in that time, VESA has updated the DisplayHDR standard with substantially tighter performance metrics,” stated Roland Wooster, chairman of the VESA task group responsible for DisplayHDR, and the association’s representative from Intel Corporation for HDR display technology. “While systems that already received DisplayHDR certification under the existing 1.0 spec are not required to re-certify their products under DisplayHDR version 1.1, we believe that many of the systems that passed the original spec will also pass the new 1.1 spec. Going forward, we expect that the majority of new devices will be certified to DisplayHDR 1.1, resulting in an even greater and more consistent HDR experience for consumers.”
What are the new v1.1 Requirements?
The DisplayHDR 1.1 specification includes a number of performance criteria updates:
- Active dimming – DisplayHDR now mandates active dimming performance levels, a feature that when adopted in displays can reduce power consumption and yield significantly darker black levels.
When we originally picked up this news piece we believed this to mean that each certification tier would require some form of local dimming technology, although the use of the phrase “active dimming” was a bit of a worry. Until now the HDR500 and above levels have all mandated the need for some form of local dimming, the technology that actually improves the dynamic range and contrast on the screen for HDR content. In our opinion this is a vital component of creating an HDR output, and without it, the lowest level HDR400 spec was largely meaningless where it was not required. The VESA press release is a little misleading we feel in how it is worded for the v1.1 updates, so we reached out to VESA for clarification.
VESA confirmed that “active dimming” should not be confused with global or local dimming, and that this update does NOT mean that HDR400 displays now need some form of local dimming technology to actually improve the dynamic range of the screen. If they operated with global dimming under the v1.0 spec, the same can apply for v1.1.
They clarified for us that “With 1.1 we use a checkerboard test, rather than a tunnel test image, to ensure that dimming is being applied in an active manner based on the image signal data rather than the image meta data being sent with the test images.” They now “check that the internal algorithms in the display are actively analyzing the image pixel data / the signal data to determine their backlight dimming level.”
This is a real shame in our opinion, and we were pleased with the original expectation that the new v1.1 scheme would mandate local dimming for all tiers – sadly it doesn’t and HDR400 still remains a problem and open to widespread abuse.
Looking at the updated v1.1 criteria, the HDR 400 v1.1 scheme also still does not require anything beyond standard sRGB gamut (95% sRGB spec), and so there is still no requirement to offer an improved colour space to support this HDR spec. Nor does it dictate the need for 10-bit colour (only 8-bit is required).
We would love to see future updates of this tier to mandate some form of local dimming support, and an enhanced DCI-P3 gamut, as providing more vivid colours is a big part of the HDR experience as well.
- DisplayID accuracy – ensures that accurate luminance and color gamut data is populated in the DisplayID or legacy Extended Display Identification Data (EDID), which enables the GPU to optimize the video signal for that display to ensure the highest display performance
- On-screen display (OSD) mode indication – any DisplayHDR-certified monitor with an on-screen menu function must now clearly indicate which modes support DisplayHDR, making it easier for users to optimize their display settings
- DisplayPort certification specification – any DisplayHDR-certified monitor that has a DisplayPort interface must also undergo DisplayPort certification, ensuring that the display performs optimally with VESA DisplayPort-certified cables and other peripherals
VESA have also introduced a range of new updates to their HDR test tool – they have also added a range of new tests and features to their test tool including tests for black-level, colour gamut, colour volume and white point.
When does the new spec come in to play?
Companies can begin certifying their display products under the new DisplayHDR 1.1 spec today. In addition, VESA will continue to allow products to be certified under the previous DisplayHDR 1.0 spec through the end of May 2020 in order to allow for products already in development that have been designed to meet the original spec, which was published in November 2017.
The new HDR 1400 certification level
In addition to updating the DisplayHDR compliance test specification (CTS), VESA has also introduced a new 1400 performance tier targeting professional content creators. This higher, premium performance tier provides a 40 percent increase in luminance and a 2.5X reduction in black level compared to the DisplayHDR 1000 tier – increasing the contrast range by 350 percent. Color gamut performance requirements have also been increased for the first time, from 90 percent to 95 percent of DCI-P3-D65 – a visibly noticeable difference compared to the 500/600/1000 tiers. Another key feature of the new DisplayHDR 1400 tier is that it requires 900 nits of brightness for full-screen long-duration (30 minute) testing, which provides for a rock-solid stable luminance-based display for professional and prosumer video editing.
The first display to carry this new badge will be the Asus ProArt PA32UCG, a 32″ display with 4K resolution and 120Hz refresh rate (news piece coming shortly). It’s aimed at professional users and can deliver a peak white brightness of 1600 nits and a sustained full-screen brightness of 1000 nits