Taking a Hybrid Approach to the SDI/IP Transition

There is a lot of discussion about implementing facility-wide all IP infrastructures. Even so, there are good reasons why selecting hybrid SDI/IP video/audio over IP gear offers a smoother and more cost-effective transition to the all-IP future.

Broadcasters are not newcomers to technological transitions. As an industry, we’ve survived analogue to digital, baseband to file-based workflows, SDTV to HDTV and now 4K UHD resolution, not to mention weathering a barrage of new compression formats.

Today, we’re facing one of the most dramatic transformations we’ve ever undergone, SDI to IP. Unlike many market sectors, the broadcast industry has been slow to jump on the IP bandwagon because it’s completely different from the SDI infrastructure on which we universally depend.

SDI is a mature, standardized technology that provides frame-accurate switching, fixed low latency, and synchronized video and audio, among other capabilities that are critical to making, moving, and monitoring video and audio signals in live, real-time applications.

Broadcasters have millions of dollars worth of SDI gear in their facilities and they still hope to realize a return on that investment.

Shifting to IP is inevitable

The move to IP is becoming more attainable as the cost of off-the-shelf commodity IP switches and other IP networking gear falls and with 40-Gig-E and 100-Gig-E infrastructures becoming more prevalent, offering greater bandwidth, which is necessary to carry that UHD load.

A single, standard Gig-E cable can replace multiple, and costly, SDI cables and the ubiquitous Internet or corporate LAN can replace a complex SDI infrastructure. And instead of having to hire specialized broadcast engineers—a skillset that’s becoming scarce—facilities can employ those with expertise in the growing IP/IT engineering field. It also becomes easier to employ virtualized server-based operations and cloud processing and distribution.

While all of these trends are pushing us towards an all-IP future, this industry finds itself in a hybrid SDI/IP state, with each facility transitioning at its own pace from the dependable proven SDI technology we’ve known to the promising new IP domain.

Standardization is key

A successful move to IP hinges on standards. Standards are critical to interoperability, encapsulation, frame-accurate switching, signal timing, synchronization, and other capabilities that the video industry depends upon.

While the industry is definitely moving towards the adoption of a particular family of standards for IP-based operations, the inability to agree on a complete set of standards is delaying the migration to IP.

Attempts to build an all-IP-based broadcast infrastructure right now are not without challenges, risks and compromises. Pioneering broadcast facilities may need to make fundamental infrastructure decisions with no guarantee that their chosen standard will be universally adopted. Or, they may find they’re locked into a particular end-to-end IP solution from a single major manufacturer, and possibly living with some gaps or compromises in that workflow.

Hybrid solutions for the transition

As broadcasters seek answers about IP-ready and IP-capable equipment options, while waiting for more clarity about new video/audio-over-IP standards, it is important to know where your vendors stand with respect to this transition.

Because one needs a crystal ball to know for sure which of the new IP standards and migration paths will ultimately win the format wars, some vendors have chosen to remain agnostic, and to support the leading standards.

With this design approach—including support for both SDI and Video/Audio IP standards within the same platform or solution—broadcasters won’t need to worry about making forklift upgrades to replace all the gear they have today. They can also rest assured that when they pull their video truck up to a venue for remote production they’ll be prepared to connect with whatever standards and formats they find there. They can capitalize on IP’s advantages today, and then gradually migrate to an all-IP infrastructure when the timing is right for them.

Expanding with IP

This transition to the all-IP domain is gaining momentum and cannot be stopped. IP has been firmly established at the distribution end of broadcast workflows for a while—for example, enabling OTT and VOD delivery of content for consumers—so it makes sense for the rest of the broadcast/production workflows to migrate to the IP realm.

But many broadcasters will hesitate to undertake an all-IP-based facility upgrade until they are certain that it will not jeopardize their on-air products and branded services. And they want to be sure that their IP infrastructure is ready for a future that will likely include the delivery of real-time 4K UHD premium services.

Where the Industry Stands on Standards

The video industry has been hard at work developing, defining and adopting new standards that bridge SDI broadcasting—with its frame-accurate, seamless switching—and IP networking. Here is a snapshot of today’s top IP standards and protocols for real-time video broadcasting and production:

The SMPTE 2022 family of IP standards

SMPTE is playing a key role in standards development to ensure reliable operations and interoperability of both compressed and uncompressed signals.

  • ST 2022-1 Deals with Forward Error Correction (FEC) related to real-time video over IP networks
  • ST 2022-2 through 2022-4 Deal with unidirectional transport of compressed video for MPEG transport streams over IP networks
  • ST 2022-5 FEC for high-bitrate media transport (HBRMT) over IP networks
  • ST 2022-6 transport of HBRMT over IP
  • ST 2022-7 Seamless protection switching of SMPTE ST 2022 IP datagrams

Video Services Forum (VSF)

The VSF Studio Video over IP (SVIP) Activity Group developed technical recommendations for Video over IP without SDI encapsulation.

  • TR-03 Relates to the transport of uncompressed elementary stream media over IP, including individual streams of video, (AES67) audio and data.
  • TR-04 Relates to utilization of ST-2022-6 media flows within a VSF TR-03 environment. This recommendation builds upon the system defined in VSF TR-03, and defines SMPTE ST 2022-6 as a video payload within those structures. The resulting method allows for the SDI multiplex, as well as the individual audio and metadata streams, to be individually forwarded through a network.


An audio-over-IP standard developed by the Audio Engineering Society (AES) that allows interoperability between various IP-based audio-networking systems, such as:

  • Dante
  • Livewire+


The Alliance for IP Media Solutions (AIMS) is an industry consortium led by broadcast engineers, technologists and visionaries. AIMS has a vendor-neutral, open-standards approach and currently offers a technology roadmap based upon SMPTE 2022-6, VSF TR-03 and VSF TR-04 to solve the basic challenges inherent in choosing the most effective way to use IP technology for broadcast operations and transition smoothly from an SDI to IP infrastructure.

Advanced Media Workflow Association (AMWA)

AMWA is an open, community-driven forum focused on the creation of timely, innovative, business-driven specifications and technologies for networked media workflows.


The ASPEN (Adaptive Sample Picture ENcapsulation) Group is a community of leading equipment manufacturers and broadcasters, including Evertz, Ross, Hitachi and ChyronHego, who developed the ASPEN format for encapsulating uncompressed UHD/3G/HD/SD over MPEG-2 transport streams. When combined with existing SMPTE standards, such as the SMPTE 2022 standards, ASPEN provides broadcasters with a flexible method of transporting video, audio, and data over scalable IP networks. ASPEN features ultra low latency with independent video, audio and ancillary data flows.

Sony NMI

Sony’s Networked Media Interface (NMI) combines SMPTE 2022 video transport standards with SMPTE timing synchronization protocols to support live video production using IP networks.


The TICO alliance is a coalition of 34 companies setting the bar for next-generation UHDTV 4K & 8K infrastructure by promoting TICO compression and video over IP standards for the new IP-based live ecosystem. The group says that with this approach, the industry can seamlessly update its existing SDI-based workflows to IP and UHDTV 4K without the cost of a complete renewal.

While the list above provides some of the Video/Audio over IP standards and recommendations currently available, their technical descriptions defy brief explanations. It is still too early to know if any one standard or protocol will prevail, but these efforts go a long way towards fostering a smooth transition to IP-based operations. 

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