Odd Erling Høgberg (NRK)

In December last year, NRK reached a milestone with the enabling of high dynamic range (HDR) in our OTT service NRK TV. The occasion was our new high-profile Christmas show for
children and families called Snøfall 2.

The journey commenced in 2016 when my boss at the time returned from a visit to a camera manufacturer, armed with photos of HDR-filled presentations. He tasked me with unravelling the potential of HDR and its implications for NRK.

The next couple of years were marked by theoretical exploration. We started to educate first ourselves, then our colleagues, on the topics of UHDTV. I searched for HDR know-how through
many channels – my primary source was the EBU’s Beyond HD working group, later the Video Systems group. Meetings and discussions with colleagues in these groups provided us with knowledge and insight, and the EBU HDR workshops in 2019 (Oslo) and 2022 (Baden-Baden) moved us significantly closer to the target.

First efforts

In 2018, we initiated our first HDR production. It demanded several publishing and distribution hacks to get it aired on our OTT platform in January 2020. The need for a systematic approach emerged, leading to the formation of a task force with representatives from the post-production, publishing, and distribution teams. Besides the sheer necessity of it, a bonus that came with this interdisciplinary collaboration was that it bridged some gaps between production and distribution teams. As a result, they now have a better understanding of the various challenges that exist within our workflows.

The establishment of an HDR test lab facilitated comparisons of different technical qualities of video clips, providing insights into how different components of a video signal affect the perceived image quality. The lab also played a pivotal role in distribution tests when we evaluated the quality with which each app and platform was playing back.

At this point, the push for UHDTV mainly came from within the technology department, and this meant we would struggle to get funding for wider adoption. We escalated our efforts towards the programme departments, as they were important for a wider adoption of this HDR initiative across the organization.

To spread awareness and interest, we created a blind-test rig presenting two technical versions of the same clip, with which our colleagues could vote for the clip they subjectively liked the best. We showed comparisons between HD and UHD, SDR and HDR, and combinations of these.

The blind test produced a lot of results that aligned well with our own findings, that contrast is the key component for a higher visual experience. Further studies also showed us that in most cases both dynamic and temporal resolution separately mean more for a perceived sharper image than spatial resolution.

Improved SDR too

In 2022, we started recording the first productions planned for HDR mastering, and a growing curiosity for HDR live emerged, accelerated by the Baden-Baden workshop. An added value
of producing live HDR is that your SDR (standard dynamic range) version also gains higher quality. This should not be underestimated; in my opinion this alone makes it worthwhile to produce live content in HDR. Currently HDR is restricted to our video-on-demand content – we will start HDR live trials this year.

Before our launch on 1 December, we performed distribution trials on several platforms. To assist our viewers with their HDR experience we created a HDR section in our NRK TV help pages, and a 30-second teaser was made available on NRK TV, showing whether the TV system in use is HDR capable or not.

With our newly established publishing and mastering workflows for HDR, we now find ourselves in a favourable position where creativity, not technology, sets the limits.

This article first appeared in issue 59 of EBU tech-i magazine.

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