Applied Technology: IP –The Practical Contribution Network

Contribution networks traditionally involved either leased or occasional use dedicated video circuits. The issue with both is the inherent expense, as the video circuit could only be used by a broadcast production, so for most of the time the investment was lying idle.

When satellite uplinks from remote locations such as sports grounds were introduced, this did little to alleviate the cost challenges. The perceived technological advancement also added significant latency, including the time taken to send the signal 36,000km up into space and back down again.

Today, telcos are moving to make IP circuits ubiquitous for trunk data, and also make them more widely available in urban areas. For productions on location, broadcasters are now likely to have access to high capacity IP circuits. In fact, for almost a decade, companies such as Nevion have been supporting broadcast contribution over IP – uncompressed or lightly compressed with JPEG2000 – since its first introduction in 2006.

The fundamental concerns cited by broadcast engineers focus on both the quality and reliability of the IP circuit. First, does it have the capability of delivering what we think of as broadcast quality: clean HD without freezes or black? Second, can the circuits be set up easily and quickly?

To pass over a telco IP circuit, the video and audio needs to be packetised. There are a number of vendors on today’s market offering this technology, but for the most reliable and robust performance broadcasters are advised to use widely recognised, open standards at each stage.

Nevion TNS4200 Monitoring probe

Nevion TNS4200 Monitoring probe

The harder engineering challenge is to ensure that the packets arrive at the destination unchanged, in sequence, and with the minimum of delay. There are techniques that can be implemented to ensure this happens. For example, RTP – real time protocol – is an open internet standard, developed specifically for audio and video, in which each packet is identified and time-stamped, to ensure seamless reassembly of the stream.

This can also be layered with seamless IP protection switching (SIPS) which allows encoders, circuits and decoders to each be duplicated for redundancy, by comparing packets and switching instantly to the alternative.

For instance, when a leading European broadcaster needed to link its studios across the country, it worked with a national telco, and with Nevion, to build an all-IP solution, based on open standards and using Nevion media gateways, monitoring probes and media network management. The network needed to link 12 main sites and 28 regional sites with bi-directional capacity.

The solution was a software-controlled network, running largely over existing 10 gigabit ethernet circuits. For the smaller, regional sites, 1 gigabit metro ethernet was used. All the connections use two different routes to both the main and backup data centres for maximum resilience. A number of the circuits carry uncompressed HD, while others, particularly the gigabit metro circuits, use light JPEG2000 compression.

One of the most important requirements of the new network was flexibility. It needed to be fast and easy to establish circuits between different points, as and when they were required. In this particular example, it was a telco that was providing the infrastructure. For some broadcasters, though, they prefer to have direct control of the network, including setting up and monitoring circuits.

Tools such as the Nevion VideoIPath media services network management software address this demand. It uses open standards, and supports OpenFlow, one of the most widely used SDN protocols. The idea is that the software hides the network complexity, so the planner simply sets up the source, the destination and the technical parameters and everything else, including route planning and automatic failover to alternates, happens automatically.

Nevion VIdeoIPath media network management

Nevion VIdeoIPath media network management

The logical extension of carrying contribution circuits over IP is a significant emerging trend: remote production. The Pac-12 network in the USA, for instance, covers 850 sports events a year by sending the cameras, microphones and commentators to site but doing all the production work in control rooms at its headquarters. IP networks carry 15 or more live camera signals back to the control centre with virtually no latency. The cost savings are significant. Pac112 estimates it saves $12 – 15k on each event, or somewhere between $10 million and $13 million a year.

Whether for occasional use contribution circuits, networks between studios and permanent venues, or full-scale remote production, IP networks are practical, proven, easily implemented and can deliver substantial cost savings for broadcasters.

Olivier Suard, Marketing Director, Nevion

Olivier Suard, Marketing Director, Nevion

You might also like...

Audio For Broadcast: Cloud Based Audio

With several industry leading audio vendors demonstrating milestone product releases based on new technology at the 2024 NAB Show, the evolution of cloud-based audio took a significant step forward. In light of these developments the article below replaces previously published content…

Future Technologies: New Hardware Paradigms

As we continue our series of articles considering technologies of the near future and how they might transform how we think about broadcast, we consider the potential processing paradigm shift offered by GPU based processing.

Standards: Part 10 - Embedding And Multiplexing Streams

Audio visual content is constructed with several different media types. Simplest of all would be a single video and audio stream synchronized together. Additional complexity is commonplace. This requires careful synchronization with accurate timing control.

Designing IP Broadcast Systems: Why Can’t We Just Plug And Play?

Plug and play would be an ideal solution for IP broadcast workflows, however, this concept is not as straightforward as it may first seem.

Future Technologies: Private 5G Vs Managed RF

We continue our series considering technologies of the near future and how they might transform how we think about broadcast, with whether building your own private 5G network could be an excellent replacement for managed RF.