I have just returned from the annual SMPTE technical conference in Hollywood, a gathering of the broadcast and media technology community where the current and emerging trends in broadcast technology and its application in our industry is discussed, debated and defined. A key topic, alongside advances in motion imaging (such as UHD, VR and AR) was the use and evolution of IP based transport in real-time environments such as studios and broadcast facilities – just as it has been for the past few years at least. This blog reviews where we are with real-time IP broadcasting today, where we are going next and why it matters.
Why we need IP
Let’s quickly reflect on why we are embracing IP in the first place, a technology that was not originally designed for our most demanding use cases and which we have lived without up to now. In a word, IP is a critical enabler. We want to introduce greater flexibility, scale and economics into our broadcast environments through the use of software based systems that run on modern generic virtualised computing fabrics in private facilities and public clouds. Such environments rely on IP as the communications protocol – if we want to use them then we have to use IP. The pros and cons of such environments have been well documented elsewhere so I won’t repeat them now.
IP broadcasting today
Our file based workflows and OTT services are already using IP, at large scale. The last domain to consider the use of IP is the area of real-time, typically uncompressed, workflows that operate in studios and playout systems. These workflows are extremely demanding due to their synchronous timing needs, high sustained bandwidth and very low tolerance of delay and packet loss.
Our first step has been to transition SDI from a physical layer implementation to a logical one – packetizing the entire SDI payload of audio, video and ancillary data into IP via the SMPTE 2022:6 standard. Thus we can deploy software based versions of our real-time broadcast systems on IT infrastructure and start to realise some of the benefits this model offers. Most vendors are beginning to supply their products in this manner and we have been able to evaluate the performance and reliability of IP in this context. But, it has not been without problems.
Hypervisors that abstract virtual machines from the underlying hardware have been used for many years in many industries and are now considered mature technologies. Running 1.5Gbps HD-SDI payloads (or higher) over these hypervisors on a sustained basis with little or no tolerance for delay or packet loss has proven challenging and troubleshooting requires close collaboration between the hardware, hypervisor, OS and application vendors. We are only now reaching a point where such deployments are viable production systems and there is still work to be done.
IP broadcasting tomorrow
Unfortunately, simple wire for wire replacement of SDI with Ethernet/IP is not going to transform our broadcast environments into the flexible, future-proofed platforms we need going forward. The industry recognised this early on and the Joint Taskforce on Networked Media (JT-NM) produced a reference architecture of a more modern IP implementation that the Video Services Forum (VSF) codified into TR-03. This technical recommendation defines a more granular, elemental approach to networked media – separating out audio, video and ancillary data while identifying the supporting functions required for distributed time synchronisation, registration and discovery and more. Multiple organisations have now stepped forward to help realise this vision practically, including AMWA, AIMS, SMPTE and others. It builds on existing standards from the IETF, IEEE and AES but requires extensions to ensure our demanding use cases are fully served. SMPTE is developing the ST 2110 series of standards to help achieve this, with much work planned throughout 2017.
We are getting much closer to a true IP and software foundation for our next generation of broadcast systems. Beyond the technologies, standards and protocols, we now need to design new ways of working that will take advantage of them and we have work to do on the associated commercial models that will enable them to bring clear business benefits that will justify the costs of transition.
We are some way down the path to the most radical change in our broadcast technology stack in many years, and we still have a distance to travel, but over the next 18 months we will see the emergence of our next generation systems that will serve our industry well for many years to come. It’s going to be an exciting and hopefully rewarding experience.
Steve Plunkett, Chief Technology Officer, Broadcast and Media Services