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14 TVBEurope The Workflow SDI vs. IP: The fight is on

IP is low cost and widely available, but how suitable is it for live video links? Will it usurp SDI, or does coaxial still have a long life ahead of it? David Fox reports

INTERNET protocol-based technology has been the future of broadcasting for years, but there have always been areas, particularly for live production, where specialist technology, such as SDI, has prevailed because nothing else could do the job so well. However, advances in IP- based systems could change that. “SDI has been around a long time and is incredibly reliable, but it suffers with a lot of issues,” says Trevor Francis, Quantel’s director of Broadcast. “It’s very much a point-to-point system, doesn’t have a metadata payload and is half duplex (either one way or the other). It also relies on a lot of legacy hardware, such as routers.” He believes that the move to

SDI over IP is “logical and probably inevitable,” and it will mean that “instead of having to have physical infrastructure for SDI, we can build virtual systems that can link anywhere to anywhere, on demand.” “There is a tendency in the industry to converge all

Open network: Axon’s OB van used its Neuron AVB/Ethernet system

networks into one technology, and the obvious one is IP/Ethernet,” says Lieven Vermaele, CEO of SDNsquare. However the enterprise IP

network, storage network, file- based media production network and SDI network each have different requirements and characteristics. To replace them with an all-encompassing IP/Ethernet network its key

characteristics would have to be predictability and reliability. With these in place, “which is possible, IP is suitable for replacing SDI and for live video links, and this in a format independent way,” he adds. “The real savings for

productions result from harnessing the flexibility and productivity of IP workflows says Mark Scott-South, director business development and

co-founder of L2tek — licensees for the BBC Stagebox IP and responsible for developing the product and the market. Although IP connections are often used for live video links, he admits there is still “a problem with accessing high-speed, well- managed QoS networks at the right price, and we don’t necessarily need to shoehorn IP into every point-to-point link where SDI is still the technology for the job.” While IP wasn’t originally designed to deliver realtime packets, “if you implement the necessary tools such as forward error correction and variable bitrate encoding in the transmission, IP can easily handle live video,” says Paul Shen, CEO of TVU Networks. Its cellular ENG transmitters already deliver broadcast- quality HD video today with sub-second latency — even over unconditioned and less stable 3G and 4G networks. “IP is not only low cost and

widely available, but it has also reduced the cost of technology

development due to the fact that it shields developers from designing for the physical layer. Depending on the application and environment, it is possible to transmit live video over IP in a predictable and reliable environment with low latency,” insists Shen. “It is a myth that IP means higher latency or lower reliability,” agrees Jan Weigner, MD and co-founder of Cinegy. “The major part of live signals on TV today are transmitted via MPLS [Multi Protocol Label Switching] or other IP connections already.” Nevion has supplied IP-based

live video connectivity to many major live events over recent years, and Thomas Heinzer, Strategic Projects, Nevion, says its “IP codec technology allows the realtime transport of huge volumes of video, audio, communications and other data in a 100% secured way over generic IP infrastructure.” “Our experience working with IP-based video and control solutions demonstrates the robust nature of IP on a daily basis,” says Jamie Shepperd, group marketing manager at Adder Technology. “Our technology delivers lossless dual-head or dual-link video across gigabit IP without latency, drop out or stutter.” Adder recently commissioned

a survey to find out how IP might be used in post. Some 38% of respondents currently use standard IP infrastructure to manage workflows, 29% use a combination of IP and proprietary technologies and just 13% use only bespoke. For those who have not made a full or partial move to an IP-based approach, the key concerns identified were the cost of upgrading facilities (38%) and bandwidth limitations (35%).

So predictable “Standard IT networks are not really suitable for transporting broadcast quality realtime video (and audio) as these networks lack mechanisms for synchronisation/timing and offer insufficient quality of service argues Jan Eveleens, CEO, Axon Digital Design. To make IP networks and

data flows fully reliable and predictable requires: end-to-end QoS, guaranteed high bandwidth utilisation, intelligent load balancing over all possible paths, scalability to a high number of flows avoiding any mutual February 2014

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