Islands In The Stream: The Art of Constructing an Audio Over IP Network on the Go

Islands in the stream: The art of constructing an audio over IP network on the go By Kevin Emmott

Monday, November 13, 2023 - 15:36

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Arena's OB Z, one of the UK's first ever IP-based outside broadcast trucks designed back in 2016, with the help of broadcast systems engineer, Chris Goddard

In last month's SVG Europe Audio Summit there was a lot of talk about IP which went way beyond what it promises to deliver and how it can enable broadcasters to be more maneuverable and efficient.

We have all moved on; IP is already delivering, and multiple broadcasters took to the stage to illustrate how IP is delivering the goods for them. But the road is not an easy one, and NEP's deputy head of sound, Neville Hooper, was very clear when he said that SMPTE 2110 networks cannot be deployed overnight.

They require time to plan, build and produce before those infrastructures work at all, he said. Network designers need to ensure they are using the right tools for each application. Planning is paramount.

There is no one-size-fits-all approach and every system has to be built around what the client is trying to achieve. Although more vendors are designing equipment that is IP compliant, it still takes time for manufacturers to actually implement them; R&D roadmaps do slip and they all work at a different pace

That comes as no surprise to broadcast systems engineer, Chris Goddard. Goddard has been designing broadcast IP networks since before there was a SMPTE standard to adhere to, including the UK's first ever IP outside broadcast trucks (for Arena) back in 2016. Specialising in audio, he started his career at SSL in the 1990's and has helped build over 40 OB trucks, designed Timeline TV's remote production flypack pods for Formula E, and played a key part in BT Sport's IP transition project in Stratford.

He knows better than most that SMPTE 2110 (ST2110) networks do indeed require time to plan. Lots of time, in fact; the BT project alone, which saw the broadcaster replace 25% of its network with IP, took over two years to complete.

It also means he is very well placed to identify where some of those planning challenges exist for anyone thinking of making the switch.

Islands in the stream

Clients usually know what they want, but there is a huge amount of detail involved to get there, and understanding the system from a technology point of view, documenting everything, and implementing processes are all things that my brain likes to do! says Goddard.

I have been exposed to IP networks from quite early on; I started working on the first IP outside broadcast trucks before ST2110 was even a ratified standard. Arena's OB X, OB Y, and OB Z were designed from the ground up to be IP, but when we started building them, manufacturers weren't necessarily able to supply compliant equipment, and not all equipment was even IP capable.

And herein lies the rub. It is not just that not all equipment is not yet IP compliant, or that different manufacturers are at various stages in their own IP journeys, or even that there are different interpretations of those same IP standards. It is all of the above.

Designing an IP network can be like building islands, says Goddard. For example, an element of the audio might be best served by using Dante, because of available products, but the main transport is via ST2110. At some point these two domains have to come together, usually by bridging them using a non-IP method such as through an audio console.

There is no one-size-fits-all approach and every system has to be built around what the client is trying to achieve. Although more vendors are designing equipment that is IP compliant, it still takes time for manufacturers to actually implement them; R&D roadmaps do slip and they all work at a different pace.

Broadcast systems engineer, Chris Goddard. Goddard has been designing broadcast IP networks since before there was a SMPTE standard to adhere to

Arrested development

It is no wonder manufacturers have a tough time keeping up, as IP standards and recommendations are also developing at pace to provide solutions to new use cases and they too develop at a different rate to how fast manufacturers can implement them.

IP isn't purely about audio; moving media around a broadcast system includes audio, video, metadata, control, etc. Managing this when your system consists of equipment from different manufacturers can be challenging

AMWA's suite of NMOS recommendations are a good example of this. While NMOS-04 and NMOS-05 are well established for discovery and management, recommendations like NMOS-08 provides solutions to enable IP networks to match tried and tested SDI workflows like audio channel mapping. Without it, we are back to using bridges to external devices like Grass Valley's Audio Live to link those islands.

Because recommendations like NMOS-08 have not hit a point where many manufacturers are designing it in, Goddard says the knock on can be significant.

Over the two years it took to plan, design and implement the BT Sport transition project, equipment specifications were constantly changing because different manufacturers were at different stages of development, and all that has a big effect on interoperability.

Not only that, but manufacturers also interpret standards differently, again impacting interoperability. Some audio equipment might only be capable of 16 channel packet encapsulation, others 64. They're both correct and conformant, but one can't interpret the packets from the other. Some interesting discussions were had to convince implementation details to be changed. All this takes time.

Moving targets and difficult transitions

Collectively, these reasons make everything within the transition to IP a moving target. If certain equipment is not i

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