Ultra HD Premium: What it Means and Why it Matters

Finally the Worlds of UHD and HDR TV Technology Get Some Clarity

If you’ve got even a passing interest in the fast-moving world of home entertainment technology you’ll know that we’re currently in the midst of a period of profound change thanks to the arrival of not one but two key new video technologies: Ultra HD (also known as 4K) resolution, and high dynamic range (HDR).

Ultra HD screens and content provide four times as much resolution as full HD ones, while HDR content (explained in detail here) offers enhanced brightness, contrast and, in most connotations, color performance.

While this all sounds fairly straightforward in principle, the reality is that particularly where HDR is concerned there’s the potential for all kinds of different approaches to existing, and all kinds of different qualities of HDR experience to find their way into the marketplace.

And until recently consumers had no clear way of distinguishing between the really good and really indifferent HDR experiences available. Thankfully this messy situation has finally been given a degree of clarity with the recent announcement at this year’s Consumer Electronics Show in Las Vegas of an Ultra HD Premium specification.

Wearing the Ultra HD Premium Logo

Developed by the Ultra High Definition Alliance (UHDA) working group of more than 30 key AV industry brands, Ultra HD Premium is designed to provide consumers with an at-a-glance way of knowing which TVs and video content are designed to deliver a really strong HDR and UHD performance.

Only products and content that conform to a carefully defined set of specifications will be able to wear the Ultra HD Premium logo, so if a consumer sees the logo attached to a product they can feel confident that it will be capable of giving them a high level of performance. 

It’s important to stress that the Ultra HD Premium logo is only in truth a recommendation system created by the UHDA; it’s not an actual standard that all products in the AV industry need to conform to.

In other words, it’s possible that there will be products out there capable of wearing the Ultra HD Premium badge that doesn't actually do so because they haven’t been submitted to the UHDA for the necessary certification tests. Still, any sort of guidance to help consumers pick their way through the potential confusions of the UHD/HDR world is better than nothing.

The key elements of the Ultra HD Premium specification are as follows. 

For TVs and Other Video Devices:

  • Image resolution: 3840x2160.
  • Color bit depth: at least 10-bit.

Color gamut reproduction: must be able to handle the BT.2020 color ‘representation’ (a sort of container for wide color range information), and display more than 90% of the Digital Cinema Initiative’s P3 color standard (the standard widely used in commercial cinemas).

For High Dynamic Range playback a device must support the SMPTE ST2084 EOTF (electrical optical transfer function - the way a screen turns digital data into visible light) and achieve either brightness peaks of more than 1000 nits along with black levels of below 0.05 nits, or more than 540 nits peak brightness and less than 0.0005 nits in the blackest picture areas.

If you’re wondering why two different recommendations are provided regarding peak brightness and black reproduction, it’s essential to accommodate both LCD and OLED screen technologies, since both are capable of producing excellent but differently ‘weighted’ HDR performances.

For Content Distribution and Mastering: 

  • Image Resolution: 3840x2160
  • Color performance: a minimum 10-bit signal.
  • Colour gamut reproduction: BT.2020 color representation 
  • HDR: Must use the SMPTE ST2084 EOTF HDR system. 

In addition, the UHD Alliance recommends the following mastering display specifications when creating HDR content masters: a minimum of 100% of the P3 color standard; a peak brightness of more than 1000 nits; and a black level depth of fewer than 0.03 nits.

One thing that’s not included in the UHDA’s Ultra HD Premium specifications for content distribution (not to be confused with the recommendations for mastering displays) are minimum and maximum luminance values, since it was felt that including these could prevent content creators from being able to get the exact ‘look’ they want for particular TV shows and movies.