One book to rule them all – Dolby helps NorDig DVB’s global reach

{{ videoLinkButton.text }} {{ videoLinkButton.text }}

Although the broadcast world is built on highly technical specifications, there’s another layer of information that holds everything together – operations. Equipment and procedures have to be configured and run day to day, with everyone involved speaking the same language and working to the same rules. I was called in to help create the AC-4 section of a practical handbook for one such set of specifications. This was as part of Dolby’s industry support.

NorDig is the specification body responsible for the DVB toolbox in the Nordic region and Republic of Ireland, but it has global influence. NorDig’s open specifications are detailed and comprehensive, providing all the encoding, system multiplexing, and receiver configurations required for linear broadcasting. Broadcasters and device manufacturers agreed on those options from the DVB toolbox that best suit their use cases. While there are local variations, a good 50% of broadcasters, including those in Australia, France, and Germany, base their systems on the NorDig spec. And where broadcasters go, manufacturers follow.

NorDig’s foundational document is the Unified Integrated Receiver Device (IRD) specification, which specifies minimum technical requirements and lists all international standards needed to build a complete DVB consumer TV receiver for both horizontal and vertical markets. It has all the technical requirements for sound, vision, text, and interfaces – such as HDMI, SPDIF, Internet and others – as well as signaling, interactivity, transport, and other standards. Dolby AC-4 was added as the only next-generation audio format in 2018. As a company, Dolby works across the entire chain of broadcast content, from creation to consumption, so when we contribute to a highly technical, focused area such as this sort of specification, we understand the broader context and can make sure that what we bring is as useful as it is accurate.

When my colleagues from Dolby’s Nuremberg office were about to finalise the AC-4 portion in the IRD specification, I was brought in as a specialist to help with integrating the codecs into the transport layer – how the audio is packaged and made available, at the highest possible quality, for all receivers, regardless of how much of the modern specification they follow.

After the NorDig IRD specification and the NorDig Test Plan was published, it was time for NorDig to upgrade its Rules of Operation (RoO). This document is the practical guide to getting a broadcast chain up and keeping it running, choosing the best default settings, and determining which changes had which effects for best compatibility with all deployed receiver devices, minimising the risk for potential disruption and subsequent user complaints. My colleagues decided I was just the man for the job, so I joined the NorDig group preparing the new draft.

When I first looked, in late summer 2019, the existing NorDig RoO showed how quickly technology had been moving. The last revision had been in 2016, but much of it was older than that. Compared to the initial version, advancements had been added piecemeal to try to keep up with technological changes, but it was time for a full revision. The cross-industry team in the NorDig RoO group did a major overhaul, improving consistency, aligning structure with the NorDig IRD specification, and adding the new technologies.

While revising my sections of the NorDig RoO, the audio section, I focused on thinking like an operator and how they’d need to use the document. I reorganised it to match the signal flow, removing obsolete details while standardising the way each component was described, and, finally, adding the new material on AC-4 formatted to match the requirements of the new IRD specification.

The process took several months and, together with associates in the drafting group who’d been working on the rest of the document, we put in what we considered the essential 80% of the material. From a consistency check with deployed and emerging devices, I got excellent feedback from colleagues in Germany, Poland, and the US. The material on AC-4 had been a challenge as there was almost no equipment on the market to refer to at that time, so I couldn’t use actual examples. Instead, I built the instructions from the technical specs.

The NorDig technical committee had initially hoped to approve an intermediate version in spring of 2020 with an update to follow, but instead of the two-step process, we were set the task of merging the audio signalling with the generic portions, producing a full version that was approved and published in late 2020.

It was a very satisfying experience. The work my fellow industry colleagues and I did for NorDig matched with the practical needs of broadcasters, distribution and transmission companies, and equipment makers. They now have a common profile on which to build their own UIs, procedures, and documents. It was a pleasure to work with the people from the drafting group, who have such a good grasp of detail, of nuance, and of goals, backed by strong collaborative skills.

Of course, internet streaming content is very important now, but linear free-to-air broadcasting is still quite healthy, both commercially and socially, as it will be for the next decade. Billions of viewers will spend hours and hours watching television – and enjoying really good quality sound – without any clue that a technical document like the Rules of Operation from NorDig is being used to keep that content coming, and that an engineer from Nuremberg, working together with colleagues from so many places and organisations, put that little piece of the jigsaw into place.

It doesn't matter how good an engineer you are if you don’t make a difference in the world. Working at the heart of the industry, with great people to set standards that benefit so many people, was a dream come true. I want to especially thank Peter Mølstedt and Per Tullstedt for driving the Rules of Operations group and NorDig Technical group forward.

Find out more: