The Serial digital interface (SDI) was first standardized by SMPTE in 1989 for SD resolutions and now includes support for 12G (and higher).
With the emergence of Internet Protocol (IP) topologies onto the production and distribution scene over the past few years, many have predicted the looming demise of traditional serial digital interface (SDI) infrastructures, saying they are too limited and regressive to satisfy today’s IT-centric operational requirements.
However, while the adoption of IP is clearly beginning to take off in many parts of the world, SDI is still heavily relied upon in thousands of existing broadcast products infrastructures—largely for the simplicity, security, reliability and familiarity the proven technology provides.
Indeed, SDI has gained a reputation as a reliable solution for many years, and since several facilities have already invested in the technology they understandably want to get the most out of their purchases before completely moving into new territory. That’s why companies supporting the broadcast industry continue to develop a myriad of new and improved SDI technology. And customers are looking to buy!
Here’s what some broadcast equipment vendors are saying about SDI’s longevity and why it’s still relevant in an industry gradually migrating to packet-based data processing and delivery.
“SDI continues to survive because it evolves alongside technology and workflows,” said Bryce Button, Director of Product Marketing, AJA Video Systems. To ease the transition, AJA has developed a number of edge devices that support SDI to IP conversion and back. “And we see a number of our customers embracing a hybrid approach.”
The AJA Video OG-12GDA-2x4 openGear 12G-SDI distribution amplifier features support for HDR video and Ross DashBoard software for remote monitoring.
For example, 12G-SDI provides more bandwidth to support higher raster, higher frame rate and deeper color workflows, including HDR. It’s also advantageous for point-to-point connectivity in critical video transmission environments, ensuring security across all aspects of production—from acquisition to recording, routing and more. And as any seasoned engineer will tell you, SDI is also simple for broadcasters to understand and implement because of its inherently intuitive video transmission methodology and metadata capabilities.
To this end, Button said that while the APAC market in particular (with the upcoming Summer Olympics in Tokyo among other global broadcast events) has shown a continued appetite for higher raster productions, which naturally demand the bandwidth that 12G-SDI accommodates, technology companies like AJA have seen a spike in the demand for 12G-SDI across a range of markets and regions.
“While the migration to IP remains unabated, it’s introducing a need for greater education and, in turn, will take more time to progress,” Button said. “By nature, IP enables more complex signal routing with greater density, but to fully reap the benefits of IP, users must get up to speed on network implementation and management methodologies. IP can simplify discovery and control while also meeting the security needs of content producers, but it also requires new methods of facility management and control.”
IP Still Evolving
Mo Goyal, Senior Director, International Business Development – Live Media Solutions, at Evertz Microsystems, said that even as the industry continues to see growth with transition to IP, the reality is that only a small percentage of the industry has deployed IP-based systems using ST 2110.
“The majority of the market is still learning about IP, and the various standards (ST 2110) and open specifications (AMWA/NMOS IS-04, IS-05, etc.),” he said. “For some markets and facilities, the cost of transitioning to IP is still high. That cost is not just the cost of equipment (still need SDI-IP gateways for legacy edge devices), but in training and support for IP. In other cases, some customers simply have no plans to go to UHD or beyond. So, for these facilities (for example: smaller stadiums), SDI remains the best choice.
The Evertz Scorpion Media Processing Platform is a signal conversion, routing, aggregation and transport platform capable of simultaneously transporting video, audio, Ethernet and data over traditional dark fiber and/or 10/25/40/100GbE networks.
That’s why, while Evertz has been at the forefront of the transition to IP for several years, it still sees a thriving market demand for 12G-SDI products.
“The initial demand for 12G-SDI started with the 2018 Winter Games in Korea as customers looked to build OB trucks for UHD,” Goyal said. “At the time, IP was still considered to be in its infancy as the ST 2110 standard was still developing and availability was limited, so customers wanted to stay with something they were familiar with. Recently, the same logic has carried over to local stations, stadiums, and esports as they are updating their technology.”
He added that many customers feel more comfortable with simplicity and the ease of use of that SDI delivers. For example, the availability of a 180x180 12G-SDI router (like Evertz’s EQX-UHD) is more than enough capacity for most common applications. The EQX-UHD also offers IP gateway line cards to enable customers to still move to IP when they want.
SDI Technology Costs Less
Mario Rodriguez, head of sales at FOR-A Latin America, said his company has invested heavily in 12G-SDI products (servers, switchers, signal processing and multiviewers) to accommodate 4K production. Among a plethora of IP technology , the company has most recently introduced a compact 12G-SDI system that’s comprised of the HVS-1200 video switcher and MFR-1000 routing switcher and MV-4300 multiviewer. FOR-A has close ties to many Asian broadcasters that still prefer the familiarity and reliability of SDI infrastructures.
“[Compared to IP] SDI is still lower in cost, easy to trouble shoot, ties in to existing infrastructure, migrates easily to 4K and can carry uncompressed signals without latency,” he said. “We see potential for SDI for 4K production not for infrastructure, as today IP for 4K is cost prohibitive.”
“Although the trend in broadcast is certainly moving towards IP, depending on the workflow, SDI is still a very popular and common choice,” said Francesco Scartozzi, vice president of sales and business development, Matrox Broadcast and Media Group. “In some 4K environments, like OB vans, for example, using 12G-SDI makes more sense than using IP.”
He added that they have seen specific applications, such as in U.S. call letter stations, where 3G-SDI equipment is being purchased as stations upgrade their current solutions because it is a familiar investment that simply gets the job done. The company is now offering the X.mio5 12G multi-channel SDI I/O card with onboard video processing and the DSX LE5 12G multi-channel SDI I/O card.
“Even though Asia is the leading market for 12G-SDI, there are parts of the Americas and Europe that are also showing increasing demand for it,” Scartozzi said. “The demand for 3G-SDI will not be going away anytime soon. Today, the key advantages are cost savings, simple interconnectivity, and lastly, familiarity and ease of use. It is easy to diagnose issues within an SDI setup, allowing for efficient on-air operations.”
What’s Your Business model?
At Ross Video, they like to pose this question to our clients who are considering IP solutions: “How does IP help your creative or business output?”.
“When they’re unable to clearly answer this question, an IP solution may not be best for them,” said Alun Fryer, Solution Architect of Infrastructure at Ross Video. “IP offers compelling solutions to the problems of large scale and distributed systems. However, this comes at a much higher capital cost (in most cases), and much greater complexity than traditional SDI solutions.”
Fryer said that Ross Video sees both SDI and IP as important to its customers and it is investing heavily in both. However, the majority of its clients continue to choose SDI as their connectivity technology of choice. For them, Ross offers its Ultrix platform that allows local SDI interconnect, routing and signal processing while offering options to include IP connectivity to address the needs of larger-scale growth or distributed systems.
The Ross Video Ultrix signal processing platform can perform fast and accurate video routing, clean/quiet switching of audio along with 12G-SDI video signals.
Comparing The Benefits
When asked about the advantages of an SDI systems design versus IP, most said it depends upon the application.
“For systems which are not huge scale or distributed, SDI solutions come at lower costs and are much simpler to design and implement,” Fryer said. “Even for UHD facilities, 12G-SDI allows well-understood system design practices to be used. There are generally fewer issues with deployment, project timelines are shorter and projects are more predictable. A large number of broadcasters don’t yet have the in-house expertise to design or maintain an IP infrastructure, leaving them less agile to deal with day-to-day system changes or technical issues.”
“Every new installation will host a different set of project requirements, and in some instances, SDI may be the preferred choice,” said Scartozzi, from Matrox. “This doesn’t mean broadcasters shouldn’t future-proof their installation, however. Best practice would be to seek out solutions that enable seamless SDI-to-IP migration. The knowledge gap and the complexity of getting a whole IP infrastructure up and running can be daunting.
“Solutions that allow an easy swap of SDI to IP and vice versa can be of great benefit,” he added. “For PC-based solutions, software vendors can leverage technologies such as Matrox’s SDI I/O cards and ST 2110 NICs, which use the same SDK, to offer both SDI and IP solutions with no additional effort. Even though the end technology goal may be IP, SDI may be a route to get the systems on air quickly and transition at a suitable pace.”
Goyal at Evertz said that the major advantages for SDI have always been its simplicity, familiarity by the engineering teams, established tools, and decade’s worth of knowledge/experience.
“We have seen that IP provides a great deal of advantages to customers (flexibility and scalability) which can lead to more efficient workflows and agility to quickly react to the changing media landscape,” he said. “However, with IP there is a big learning curve and increase in complexity. Both of those concerns will get resolved as more deployments occur, tools mature, and knowledge expands. It’s only a matter of time.”
AJA’s Button agrees that security, reliability and backwards compatibility are key drivers in the continued use of SDI in a range of broadcast workflows. AJA Video offers copper- and fiber-based 12G-SDI across its product families to address customers' SDI needs, from its openGear solutions to mini-converters, HDR tools, routers and desktop video I/O tools—with the latest solution being the HDR Image Analyzer 12G.
The latest generation 12G-SDI cable supports extended HD/4K signal transmission distance on a single coax while minimizing weight and space compared to dual or quad-link configurations.
“SDI-based fiber solutions have evolved to enable distance extensions where required,” Button said. “Routing density is a key consideration and an advantage of IP workflows and will continue to offer the most flexibility moving forward for many areas of production and distribution. IP further promises greater capacity as well as easy device discovery on a facility network. All that said, the reality is that we will likely be living in a hybrid world for the foreseeable future.”
While IP Is The Clear Path, SDI Will Remain A Viable Option
All of the companies surveyed for this article said that SDI— which was first standardized by SMPTE in 1989—will remain a major part of video production infrastructures for several years to come. But how about a decade from now?
“I would say ‘yes,’ given the expectations that broadcast equipment have life spans of 7 to 10 years,” Goyal said. “However, it will likely be in small pockets of legacy edge equipment. The move to IP is still the right path for the industry as a whole. With more IP-based products coming to market, you will see the legacy equipment slowly being displaced.”
“Regardless of each new technological evolution to hit the market, SDI has been and continues to grow into an incredibly resilient form of video transmission for the professional video environment,” said Button. “It would be foolhardy to make any predictions in an industry where technology is evolving so rapidly, but we can certainly expect SDI to continue as a mainstay in many video environments for quite some time while IP vigorously forges forward.”
“There is no doubt that IP will be much more ubiquitous in ten years, however there will still be a significant amount of SDI still in service,” Ross Video’s Fryer said. “IP solutions will become less expensive over time, be easier to implement and be better understood by broadcast professionals. However, it will be much longer than 10 years before anyone can really declare ‘SDI is dead.’”