Two sets of fans remember England’s clash with Sweden in the 2018 World Cup with particular venom. Swedish fans, who lost, and England fans watching on BBC iPlayer, where the stream went down with three minutes to go.
These fans, who took to Twitter to demand financial compensation, weren’t the only victims of technical mishaps at the last World Cup. Latency – the amount of time between a video frame being recorded and it being shown on TV – was another bugbear. The latency of an online stream can be much bigger than that of traditional broadcast TV. We all feared an errant WhatsApp message or telling cheer ruining the surprise of a goal.
A large portion of the UK will be concerned about a repeat of this outage when England take on Scotland on Friday. But fear not! ITV and the BBC have been hard at work these last three years, preparing for this moment: you may not notice it, but we are watching a far more stable stream than three years ago. “Certainly that’s been our main focus,” says Henry Webster, head of media services for BBC digital distribution. “What we did see at that time were some particular challenges that we weren’t very well set up to face. And we have done a significant amount of work between now and then to get us into a much better place.”
It’s not surprising that streams aren’t yet up to scratch with live broadcast: from a broadcast technology perspective, they’re competing with more than 60 years of development. “Broadly, the challenge is that you are making a kind of one to one connection with all of the audience, and you need to scale appropriately to manage that,” Webster says. “So broadcasting, traditionally, has been either sticks on hills or satellites in the sky, which cast a single signal to a large number of people, and is a very efficient mechanism for sending information out to lots of people at the same time.”
Streams, on the other hand, reach you in a different way, and there’s a lot more things that can go wrong. “A lot of it has to do with the way that video was packaged up and sent down the internet: it's sent in chunks of six and 12 seconds,” says Steve Forde, ITV’s director of digital products. “And the higher the quality of that video, the more the latency really, because obviously, you’ve got bigger packages of data to send down down the internet.”
In order to reach that holy grail of parity with traditional broadcast TV, companies are shooting for what Forde calls “ideal streams”, a series of factors that make up a quality viewing experience. For instance, start time – how long does it take somebody to get from pressing play to the first video frame? How much buffering is there? How long does it take to transition between the ads and the show?
Finally, and most importantly, they must eliminate dreaded “fatal errors”: people dropping out, as happened on the BBC stream of Sweden versus England. Factors like these are analysed in the months and years between tournaments and big events and tweaked live in the moment. “When the stream is on, we make changes on the fly,” says Forde. “There are so many eyes on the screen it’s a bit like Star Trek Enterprise.”
The scale of streaming is also skyrocketing: audiences are getting bigger and bigger, while expecting streams to get more and more reliable. About 3.9 million people streamed the very first England group game against Croatia on Sunday live on BBC, a new record. If England get further in the tournament, this record is likely to be broken again and again. “What we know is that every year is bigger than the last in terms of the number of people coming to watch,” Webster says. “And so our primary focus is very much on making sure that we can support that new audience scale at any given time.”
Sport tends to have massive numbers of viewers concurrently, but they tune in slowly to the stream, while something of equivalent popularity such as Love Island (and the recent Harry and Meghan interview) has everyone tuning in at once to watch from the very beginning, a massive surge of pressure. Nevertheless, despite this slow build-up, sport can experience huge bursts in activity at any random moment. For instance, in the Ukraine versus Holland game, the ITV stream experienced a huge burst in activity from Android and iOS users, which Forde attributes to viral discussions on social media.
Working from home complicates the issue further. The matches going out at 2pm and 5pm have to contend with a huge swathe of Britain using the internet to work. “It adds to the complexity, because we have to scale up our services and our content distribution network to make sure we’ve got the network capacity we need around it,” says Forde.
All these concurrent viewers pose unique engineering challenges: retaining stability is all about scaling up network capacity, and being ready for more streams taking place than anticipated. Forde explains that moving from hardware to the cloud has helped them, too: it’s easier to quickly adjust for scale to deal with surprises like the Holland Ukraine game. “Our ability to auto-scale within the cloud is [better]: if an audience, for instance, takes us by surprise, in the past, when we were on hardware that would have been a big engineering challenge we would have had to predict upfront,” he says.
One thing ITV has to consider, which the BBC doesn’t, is advertising. Here there have been big changes. It now uses something called dynamic ad insertion for itv.com and mobile, its two biggest live streaming platforms. Basically, it has replaced standard TV ads with far more valuable targeted ads: where the ads on telly are monolithic, the ads you see on the stream will be personalised to you. “This is no insignificant feat,” says Forde. “We’re the biggest commercial streamer in the UK.”
Most of the improvements to streaming have gone on behind the scenes. “We have a number of caching layers and rely on several third party ‘content delivery networks’ to ensure our media packets reach the audience,” Webster explains. This helps us manage the load of the millions of connections, and means that HD audio and visual quality has improved, for instance. “It’s difficult to see unless you’ve got a really good set of eyes or really good screens,” says Webster.
Eliminating lag has been a slower process. “The challenge there is that it really is a trade-off between quality of service and how quickly we can deliver it or how close to real-time you can deliver it: it’s a very direct trade-off,” says Webster.
When it comes to lowering latency, it’s important to move cautiously, Webster explains. “We don’t end up in a world where we get lots of buffering or we get big failures,” he says. “What’s much more important to our audience is having a consistent, reliable experience, then whether it’s a minute behind, or 30 seconds behind, or five seconds behind.”
For now, then, you can mostly be confident you’ll catch the whole game, but you may want to stay out of earshot of your local pub.
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This article was originally published by WIRED UK
