As the industry moves toward all-IP infrastructures, broadcasters, service providers and content originators are seeing some very compelling technical and financial factors that are fueling this migration. However, many operators are not ready or in a position to make a complete shift to all-IP playout solutions or infrastructure. Rather, they are faced with a more gradual transition that demands they work both with existing SDI systems and an increasing amount of IP-based systems. As operators seek out the benefits of IP, they also must deal with new challenges presented by hybrid SDI/IP media environments.

The Promise of IP

In transitioning to IP, operators stand to gain much greater agility in transforming their technology infrastructure to accommodate future services. Broadcast, cable, satellite and IPTV services must co-exist with video on demand (VOD) and over-the-top (OTT) services that allow customers to watch content on any device at any time. Consequently, flexible, scalable workflows have become essential to programmers and content providers’ ability to remain competitive. By making the shift to an all-IP world, these operators become better prepared to adapt to rapidly changing market dynamics.

Moving away from SDI to IP infrastructure allows operators to build functional systems using commercial-off-the-shelf (COTS) hardware, virtualization and software-defined networking. Already proven in the enterprise realm, these approaches afford media facilities critical gains with respect to processing and scalability.As a result, playout servers and services need to adapt to the IP world. This opens the door to all-IP delivery chains.

The ever-increasing pressures to reduce total cost of ownership (TCO) of broadcast infrastructure also makes IP infrastructure appealing. Leveraging IP infrastructure to run software-based media processing applications on COTS servers, operators can improve their efficiency while reducing the amount and cost of equipment deployed, as well as associated cabling, space and power. Using software-based media processors, operators also can take much greater advantage of the ever increasing levels of function integration as they become available. This leverages what has already been accomplished by channel-in-a-box and integrated-channel-playout solutions – by collapsing previously discrete functions on a single platform, operators realize further capex and opex savings that contribute to lower overall business costs.

Together, these factors make the shift to IP-based playout an attractive proposition as part of establishing a versatile and economically sustainable video ecosystem.

The Challenges of SDI-to-IP Migration

Given the substantial payoff promised by IP infrastructure and workflow, a great deal of pioneering work is being undertaken to demonstrate the viability of an all-IP world. A variety of interoperability and proof of concept systems of varying types have been tried and tested.Already, many fundamental questions regarding the feasibility of IP network-based solutions in broadcast applications have been addressed.

Thanks to advances in network technology, packet switching, error protection, as well as in the codecs and standards supporting the use of IP infrastructure for media, compressed video signals transported via IP are now an essential element of broadcast infrastructure. The transport of compressed video-over-IP networks began in distribution applications and now is actively employed throughout ingest, content creation and playout workflows. Nevertheless, as they take on the move to an all-IP infrastructure, broadcasters, service providers and content originators face nontrivial challenges.

For one, SDI is heavily embedded — especially for production and playout applications — and is a barrier to many operators to make a complete switch from traditional coax-based SDI infrastructure to IP. Even with the construction of IP islands, traditional SDI-oriented users need to expand their technical expertise to address new IP-related concerns.

The topology of a media infrastructure is complex. When considering migration to IP networks, operators accustomed to SDI with genlock-based sync and frame-based timing can fail to understand some of the key architectural differences. For instance, while the bidirectional nature of IP may be obvious, the need to segregate traffic may not be. Measuring and maintaining quality of service (QoS) also becomes a priority as it becomes essential to guarantee IP network performance. Security of the IP network also warrants consideration, particularly when that network extends beyond the studio or broadcast facility environment.

Efficient use of resources is a primary issue in the hybrid or transitioning SDI/IP environment. Once the operator brings content into the IP domain, many of the techniques associated with SDI workflows change or become redundant. Timing and control approaches, for example, must be re-evaluated to facilitate the separation of these functions as layers, apart from the signal flow.Video and audio switching, routing and distribution are other areas in need of attention.

Use of broadcast-specific, SDI-based solutions alongside IP-based systems also contribute to inefficiency by introducing greater complexity to the workflow. Fortunately, an appropriate SDI-to-IP bridge — and standards such as SMPTE ST 2022-6 — can help operators to avoid the expense and complexity of encoding and decoding multiple times to accommodate existing SDI equipment. As time passes and technical innovation continues and interoperability become ubiquitous, it will become easier for operators to establish a streamlined broadcast infrastructure that combines light and heavy compression techniques with uncompressed signal flows over IP.

While ongoing refinement of media technology will address many of these issues, operators currently face challenges stemming from a lack of needed standards or, more accurately, lack of interoperability of encapsulation technologies, timing, and network infrastructure. Although proprietary technologies can work on a limited basis, they ultimately fail to offer the flexibility and security to video playout and distribution applications.This makes interoperability a key need for IP-based solutions.

The Hybrid Facility of the Near Future

All-IP infrastructure and workflows promise more efficient, less-expensive media processing for everything from OTT to UHD content. To exploit the benefits of IP fully, however, operators in transition will often need to accommodate both SDI and IP in a simplified hybrid environment.

In order to realize a strategic shift that is in line with both their technical and financial requirements for playout workflows, many operators can use integrated architectures to bridge the gap between baseband and compressed workflows with simultaneous SDI and IP functionality.While this can be as simple as conversion equipment that converts IP to SDI and vice versa, a more sophisticated and agile approach allows simultaneously support SDI and IP I/O and processing with full playout, channel-in-a-box and switcher capabilities.

Ongoing development across standards and solutions will be essential for those needing a hybrid SDI and IP solution. This provides the underpinnings for practical IP workflows and enables SDI and IP I/O capable products to step in and out of the IP domain.

There are many IP workflows already in place today, even in the area of playout where SDI is still firmly rooted. These tend to be around file interchange, transcoding, editing and file-based QC processes that feed the playout part of the workflow with viable assets.Evolution of compression techniques along with IP infrastructure and standardization will also support the use of IP playout over a wider footprint.The new breed of software playout solutions will be able to adapt more quickly to increasingly changing demands of broadcasters, service providers and content originators.

While the rapid developments in IP will help to define the hybrid facility of the future and shape the transition to an all-IP infrastructure, operators must also consider how far they can or want to change their established practices and infrastructure.In some cases the march to an all IP workflow may result in a change of workflow as well as infrastructure to take advantage of new efficiencies that are enabled by IP.Whether working with trusted integrators and vendors or internally developed approaches, operators can identify the solutions, workflow and IP migration path that best suit their playout objectives in both the near and long term. The move to IP will ultimately lead to greater benefits in flexibility, scalability and efficiency that allow broadcasters, service providers and content originators to adapt to accelerating change in content delivery and consumption.