The interesting part about the SDI-versus-IP debate is that those who haven’t migrated to IP yet are wary of fixing something that isn’t broke as far as they are concerned. This will eventually lead to a dead end, as those who have made the transition and never want to go back will confirm.

True, from a broadcaster’s point of view, IP requires a different mindset and other skills for everything happening under the hood. But the whole idea of going IP is that there should be no noticeable difference for operators, even though they can achieve a lot more than would be possible in the baseband domain. Imagine being able to connect any studio or any outside location to any control room, not just on-campus, but anywhere in the world, all at the press of a single button on a touchscreen or tablet, or on a hardware panel.

Two examples of the benefits of this fast way of switching among countless input signals spring to mind. The first is a typical election night with cameras, reporters and guests in different parts of the country. Switching from one location to the next used to involve patching a lot of SDI cables. When performed under pressure, because nobody wants to leave the viewers at home waiting, chances are that the odd jack ends up in the wrong socket, causing issues that tend to make a lot of people nervous. By comparison, hardly anything can go wrong as long as you press the right button. Clearly labeled buttons should make this foolproof.

The second example involves sports tournaments, such as world, European, Asian, Latin-American, etc., championships and Tier-1 athletics jamborees. Today’s pace of compelling storytelling means that host broadcasters need to move from one location to next in a split second, complete with all the signal patching this may involve. One might argue that this was perfectly possible with satellite uplinks and enough incoming lines at the international broadcast center (IBC). But it requires

a lot more equipment and adaptation technology, on-site, which tends to be frowned upon these days because of the much heftier carbon footprint. Besides, it is a far cry from a single button press.

It’s Not Either–Or

A common misunderstanding is that broadcasters and content producers need to either work in the baseband SDI or in the IP domain. As explained elsewhere, backwards-compatibility is taken for granted in the broadcast and AV sectors. In fact, most operations use a hybrid infrastructure, for obvious reasons: their SDI equipment still produces sterling results, and so replacing it would be a pity. Secondly, some tools commonly found in almost any control room do not yet speak IP natively.

Neither means that an IP backbone would be overkill. Quite the contrary: operations that keep growing are very likely to quickly hit a glass ceiling with respect to the number of inputs and outputs on their SDI routers. An IP backbone has an almost unlimited capability to accommodate more ins and outs as they become necessary. Let us therefore agree that next to no hardware purchased earlier needs to be replaced quite as radically as an SDI router with no room for expansion.

The trick is to use gateways, i.e. devices that translate incoming and outgoing SDI signals into SMPTE ST2110 essences, and back. They allow users to leverage their existing pool of SDI cameras, video switchers, and so on, for as long as this makes sense to them. Flexible gateways, like Lawo’s .edge, don’t stop at accurate translations either. They also offer processing functionality for those who wish. One such function is automatic reshuffling of the four legs of quad-link 3G SDI data in a UHD context: if the cables are connected in the wrong order, “UHD Link Rotate” will automatically sort them before the 12G IP streams are generated.

A second handy functionality allows users to activate JPEG XS encoders for the required video feeds, to transmit large amounts of data with lossless compression. This reduces the bandwidth requirements for high-resolution video feeds. And the list goes on: an optional proxy generator license is able to transmit incoming video feeds both at the original resolution and in several downscaled versions, making down-conversions for multiviewers, streaming applications, etc., by a dedicated video processor elsewhere obsolete.

Once all data are on the IP plane, they can be processed, shuffled and used in real time by operators in vastly different locations. It would therefore appear that SDI and IP have the potential to live happily ever after and shine for years to come.

Common Denominator

IP often means different things to different people, and Dante is far from the only transport format associated with IP. Other common formats include NDI and SRT, both of which used to be frowned upon by broadcasters, because the quality of the end result was deemed substandard. This has changed: during the pandemic, quite a few broadcasters realized that it wasn’t the picture quality that “sold”, but rather the ability to tell compelling stories right from where the action is. All this requires is tools that allow the provision of decent video and audio quality. Just think of the benefits of being able to talk to someone at the scene during a breaking news flash. In all fairness, the quality of devices that support SRT and/or NDI is becoming so remarkable that public broadcasters, who wouldn’t have touched SRT or NDI with a barge pole only a few years ago, now investigate the possibilities.

Besides, SRT is downright handy for sending productions over the public internet when no fiber-optic WAN connection is available.

Operators sold to the broadcast IP idea think of the SMPTE ST2110 suite of open standards as the one-and-only IP. The standards of this suite are a safe bet, because they are open, i.e. not proprietary, and so using them requires no license fees. The standards are administered by SMPTE and therefore unbiased, describing only what a solution must provide, and how, to function flawlessly in an open environment where everything hinges on interoperability.

The teams that have delivered some of the biggest IP projects to date remain convinced that ST2110 has the power to remain the common denominator of choice. They are adamant that having all their video, audio, control, and metadata essences in ST2110 for the best part of their processing stack provides them with the flexibility to experiment with different compression formats and increasingly sophisticated workflows, including those based on SDN for more security and flexibility regarding device pooling. Just think of the savings this strategy enables. On the input and output sides, however, current and future IP solutions will need to support any format that operators require, whether JPEG XS, H.26x, NDI, SRT or newly added formats.

Mix & Match Software & Hardware

Just in case you thought that ST2110 IP is becoming obsolete as users migrate to the public cloud, think again. First, the rumors of everything moving to the cloud are slightly exaggerated, not least because of a lack of transparency regarding the bottom line: there have been quite a few nasty surprises with respect to egress costs, i.e. the fees charged for backhauling content from the cloud. Plus, some broadcasters and content producers still feel a bit uneasy about the safety of their content.

This was one of the reasons why Lawo released its HOME Apps platform last year. Firmly rooted in SMPTE ST2110, they represent the abstraction of processing functionality from the hardware that does the number crunching. And by “hardware”, we mean standard servers on premise, in a private datacenter or in the public cloud. So, it’s up to each outfit to decide where they will be run. A mix of all three is also possible.

In the broadcast industry, most vendors’ money is on “software-defined” tools, whether on FPGA-based hardware or generic servers. Given the demand for utmost agility, a platform that allows users to shift processing capability to where it can be run most effectively, on demand, leaves all options open, especially if the required functionality can be leveraged indiscriminately on an FPGA-based hardware device or by spinning up an app. Such an approach needs to be so transparent that users are unable to tell where the processing capability is provided—on a processing device or a standard server, with switches between the two happening in a split second.

A Solid State Of Managed Flux

From the above, it should be clear that the best has yet to come for ST2110 IP. It works in both directions: SDI devices you want to keep using, for whatever reason, can easily be added to the IP backbone and infrastructure, and processing functionality can very well be supplied by microservices that are both easy and highly flexible to spec out and fire up—just for the project at hand or long-term.

In such a scenario, audio or video received from an SDI device can be processed on a standard server, if that is more convenient, or on an FPGA-based, bespoke device that still has some capacity to spare. In either case, the processing capability can sit anywhere in the world. The only precondition is that any workflow you envision has ST2110 IP at its core.