US Open Golf Puts Spotlight On Latency And Scale For Live Streaming

Every big global sporting event exerts stress on streaming infrastructures and challenges providers to deliver further improvements in the viewing experience as demand and traffic levels go on increasing. The 2022 US Open Golf Championship in Brookline, Massachusetts, is particularly under the spotlight as the world’s third golf major of the year, brooking comparisons with coverage of the first two already completed.

Those two events showed that progress is not always linear as they went backwards in failing to provide 4K feeds for example, denying streaming services the opportunity to deliver at the higher format, even though FOX Sports had first done so for the US Open four years ago in 2018.

The official broadcaster NBC Sports did not confirm whether there will be a 4K feed this year, although that is quite likely given that it provided live transmissions of the Winter Olympics in 4K HDR and Dolby Atmos in the US earlier this year, available to Comcast, Verizon, YouTube TV and all those carrying the signals.

In other respects, the US Open 2022 could also lag behind what is possible but at least be at the forefront of what is realistically achievable for streaming large events at big scale, as the industry matures and coalesces around common principles. One example of this is over ultra-low latency with the realization that it is not worth the cost of squeezing as much latency as possible out of the stream, as is necessary for video conferencing with its requirement for almost instantaneous two-way communication. Such stringent requirements are met by the WebRTC streaming protocol.

WebRTC is one of three principal protocols designed for low latency streaming, the other two being SRT (Secure Reliable Transport, and RIST (Reliable Internet Stream Protocol). SRT and RIST are quite similar technically and both aimed at live streamed video where the primary goal is to reduce latency to levels comparable with or even slightly below traditional broadcast, in the region of 6 seconds. WebRTC offers lower latency still by cutting error correction to the bone, having evolved for interactive applications including video conferencing where even a few seconds end to end delay renders a service virtually unusable.

There was at one time some traction behind WebRTC, perhaps in a modified form, for streamed video, given that support for interactivity is also required there. But when viewing video, rather than communicating via that medium, the latency budget is a little more relaxed because applications like action replays do not require absolutely instantaneous response, just near real time. Therefore, as in the case of US Open Golf streaming, WebRTC has been avoided, most likely in favour of SRT.

NBC Sports has previously deployed SRT for streaming of other events, such as football World Cup qualifiers and the 2020 Olympics. More significantly, NBC Sports’ VP of Transmission Operations and Engineering Chris Connolly has confirmed that its use of SRT was not confined to specific high-profile events, but to improve quality of ongoing sports broadcasting generally, so it seems inconceivable it would not be employed for the US Open Golf.

Connolly views SRT as a pragmatic response to the low latency challenge, balancing cost of implementation against gain in QoS or user experience. For a large broadcaster of popular events such as the US Open, NBC Sports has calculated that the impact of a slight deficit in latency compared with WebRTC will have only a small impact on numbers of viewers on the day and therefore subscription or ad revenues.

While SRT enables streaming at low latencies comparable to traditional broadcast, it does not on its own guarantee that video will be delivered consistently at high quality free from artefacts, as well as variations in delay. This is in the domain of OTT monitoring, for which NBC Sports selected technology from TAG Video Systems for previous events, such as the Olympic Winter Games in Beijing, China, during February 2022. NBC Sports uses TAG Video Systems’ MCM Multichannel software-based monitoring and multiviewing system end-to-end monitoring across the whole video network, including at the production level for delivery of uncompressed ST 2110 and JPEG-XS signals, as well as for delivery over its Peacock OTT platform and for the CDNs involved in transport. One advantage of SRT is that it can be used across the whole cycle, including video contribution, and so dovetails with the monitoring.

This trend towards use of SRT across the whole video chain has also led to traction for vendors less directly involved in coverage of the US Open. One is LTN Global, a provider of video ecosystem technology based in Maryland, USA, which in January 2021 announced integration of SRT into its Live Video Cloud (LVC), a high-capacity live video management system. As LTN Global put it, this now enables complex and rich live video workflows for both transmission and distribution. “SRT is applied to contribution and distribution endpoints as part of a video stream workflow to optimize streaming performance and deliver the best quality and lowest latency video at all times,” said the company.

This SRT upgrade enables video service providers to exploit the MPEG Transport Stream (MPEG-TS) as the internal protocol for rich metadata, as well as low latency, aimed particularly at live sports broadcasters, as well as news organizations. “The SRT support simplifies the distribution of complex workflows and allows customers to leverage this capability for multiple use cases,” said LTN Global in its release. It also allows localization of content within tight latency budgets, which is valuable for large scale events of global interest such as the US Open.

Although less relevant for a large broadcaster such as NBC Sports, or Sky in the UK, there are some service providers, as well as individual events, that deliver content more intermittently and cannot justify the expense of maintaining permanent infrastructure. This can be catered for in public cloud networks, which avoid individual service providers having to overprovision their capabilities to cater for peaks in demand and traffic that only occur during major live events. This has spawned products that support such variable demand cost effectively in conjunction with the cloud, such as Qligent, based in Florida, US. The company’ s Dynamic OTT Monitoring system was developed to avoid the cost of maintaining a permanent monitoring infrastructure by combining the QoS, QoE and Compliance Monitoring of its flagship Vision system into a single package for temporary services in the cloud, allowing providers to turn on and off as needed and only pay for what they use.

Another aspect of sports streaming is the scope for innovative applications that cannot be so readily enabled by legacy platforms, which can embrace participants as well as spectators, involving live data and also various forms of Extended Reality (XR). This can involve implanting intelligence into the ball itself, which potentially includes football, rugby, cricket, and tennis, as well as golf.

Riedel Communications early 2022 became one of the first in the broadcasting technology sphere to engage with smart balls in a partnership announced with its fellow German IoT sports start-up iotis, based in Hanover. Iotis had just launched a smart soccer ball that generates live data from integrated sensors, with the aim of providing digital coaching when paired with the firm’s training app.

Users can view real-time data to assess their performance as an aid to coaching, with iotis arguing this will add a new dimension to ball sports. Riedel aims to be involved with plans to extend to other ball sports, starting perhaps with table tennis.

For now though, scale and latency remain the fundamentals of sports streaming, beyond consistent quality, according to Chris Wilson, Director of Market Development, Sports at MediaKind, based in Texas, USA. “Addressing the issue of scale and latency is an absolute priority if we are to realize a streaming world of live without limits,” wrote Wilson in a recent blog. “Audiences are increasingly less forgiving, and the top-tier sporting rights owners are no longer tolerant of streaming services that are less performant and potentially impacted by broadcast services.”

Wilson believes that 2022 is the year that sports streaming finally catches up with broadcast feeds in terms of latency. But he noted that this is just one latency hurdle, another being equivalence to social media content, and a third the ability to incorporate data feeds in near real time. As noted earlier, more stringent latency targets can be met with WebRTC in principle, but in practice sports streamers will instead tweak and optimize SRT or RIST further.

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