SDI OR IP for Broadcasting

Traditional broadcasting is facing difficult times around the world. Spectrum is getting costlier and scarce and competition is growing from alternate delivery platforms. Multicast does not work well over the internet, although it works well within managed networks. Unicast delivery over IP is excellent for taking different content to different people, so it is suitable for VOD or Netflix type streaming. But unicast delivery of the same content to numerous viewers can have significant scaling issues, especially with regard to cost of delivery.

IP connectivity is nothing new in broadcast. It has been used for years to move content between servers and shipping contents from producers to editors and broadcasters. The objective behind migrating to IP should be to save cost, enhance reach, and generate new revenue streams.

IP-based systems are becoming the norm when designing large green field new projects or for major system upgrades. However for smaller scale systems, IP infrastructure may not offer any operational edge or cost saving over a traditional SDI-based architecture. It is a matter of choosing the right solution for the situation. The IP facility is inherently flexible and scalable. Adding new channels or a different OTT service or introducing 4k or HDR ultra HD is relatively easier.

However, there is still work to be done on discovery and registration. A traditional broadcast infrastructure is inherently plug and play. We need to be able to plug a device onto a network and have it recognized, authorized, and made available. Unlike IP, SDI is quite secure from hacking.

Advantages of an IP-based broadcast facility:

Easier for multi-platform. The ability to include IP services into the broadcast multiplex along with the large coverage area and the high bit rate capabilities, allow broadcasting systems to constitute flexible broadband IP networking infrastructures complementing existing and emerging wireless access networks such as 3G, WiMAX, and LTE.

Future proof platform. Broadcast stations are now building out a high-performance computing infrastructure and laying over software-based solutions to implement the workflows that fit their needs. The dramatic increase in signal count and the inherent scalability of ethernet provide a possible future proof solution to the growing port count and higher resolution requirement of the core video routing system.

Borderless broadcasting. Broadcasters are moving to compete with the global scale, local reach, and rapid response of Amazon Prime and Netflix. Provision of broadcast TV services over the networks and over the internet is further fading the borders between the IP/networking and broadcasting worlds.

Generic IP equipment is cheaper than a dedicated broadcast kit. IP uses more commodity IT equipment that brings down cost and gives editorial more options.

File-based workflows. However, this can be achieved without going to IP also.

Easier to adopt cloud, SaaS, and virtualization. The transition to IP and software-defined video (SDV) infrastructure will eventually see them move from bricks and mortar to cloud-based content suppliers. A software as a service (SaaS) model delivers economies of scale and replaces manual workflow with automation. Virtualization removes the geographic dependencies that have previously limited video playout. Broadcasters can achieve regionalization, localization, and even hyperlocalization of channel content. A software-defined network located in the cloud unites these processes and links ad sales, scheduling, traffic management, and video servers into a single workflow accessed from desktop browsers.

Simplified switching, with redundancy. One of the greatest enabler of change to IP had been the availability of 10 GbE IP network hardware. Broadcasters can now fit four to six channels in a single 10GbE cable. Because ethernet is bidirectional unlike SDI, that means more signals in both directions.

IP will enable UHD. Today it takes four HD SDI cables to carry a single 4k signal. A 10 GbE cable can take that signal with a light compression. 25 GbE will provide UHD 60 uncompressed. (Soma) Scalability of ethernet will provide broadcasters a platform that will grow more easily and change with their needs.

New efficiencies and opportunities. Outsourcing operational processes to private data centers offers broadcasters not just CapEx and real estate cost savings, but the strategic ability to flex up or down to launch new ventures, respond to short-term demand spikes with pop-up channels, and change aspects of channels in real time.

Direct access to customers. IP allows going straight to the customer.

Alternative to ATSC 3.0. With the technology now accessible to broadcasters as well, they will not have to pin their future solely on ATSC 3.0. Broadcasters now envision becoming a datacaster, not a broadcaster.

Issues in Dealing with IP
There are several issues to be tackled when dealing with IP in a broadcast environment. Some of them are:

• The first of these is that broadcast digital video is high bandwidth. 1.5Gb/s SDI (SMPTE 292M) and 3Gb/s SDI (SMPTE 424M) for uncompressed HD signals, 6Gb/s SDI (SMPTE 2081) and 12GB/s SDI (SMPTE 2082) for UHD-1 (2160×3840, 10-bit, 4:2:2 at 60 fps)
• Broadcasters need 10Gb connections for HD and 40 or 100Gb connections to support UHD
• Running multiple 12Gb/s high frame rate signals through a network router will require massive backplane bandwidth. For example, a modest sized HD video router of, say, 40 × 40, provides a potential switching bandwidth of almost 120Gb/s. At 4k, this increases to almost 500Gb/s
• Some of these issues can be tackled by compressing the video signal. JPEG2000 and TICO offer visually lossless light 4:1 compression, but then one needs encoders and decoders
• Broadcast and production organizations do not change technology on whims and fancies. It is either driven by program requirements or as the current technology fails or reaches the end of its lifecycle
• We need to put more effort into training, education, and sharing knowledge between the broadcast side and IT side of the house of a broadcast facility
• A set of standards are needed that are as ubiquitous in broadcast as SDI, with standardized connections on each bit of kit
• SDI is so embedded within broadcast facilities and workflows that it cannot be swept away overnight by IP. For the majority broadcasters, the transition to IP will be gradual, starting with IP islands floating in a sea of SDI. Over time, we can expect this position to reverse to the point where the sea is IP and the islands are SDI
• The adoption of a file-based workflow, multiple platforms, and formats has come faster and is more disruptive than any other changes
• Quality control and monitoring requires sophisticated new tools in IP workflow. The test and measurement component will move from the waveform scope to IP packet analyzers
• The brittle, time-sensitive nature of video does not play well with the proven but lossy nature of IP – even less so on shared and unmanaged networks like the internet

The key is to migrate to IP at a broadcaster’s own pace and ensure they have the ability to evolve in a hybrid SDI–IP infrastructure.

It is predicted that the SDV market will top USD 10 billion by end 2018. The benefits of software that have pervaded the IT industry are about to have the same impact on the video industry as well.

BBC CTO Mathew Postgate says. “I think we will have a large amount of IP activity in 5 years, but in reality the transition from SDI will take a number of years.”