BBC iPlayer has hailed its summer of streaming the World Cup and Wimbledon in 4K for the first time a success.
Ultra High Definition video (also known as UHD and 4K) is slowly becoming the future of home video, as improved TV sets become more affordable and internet speeds get fast enough to support the higher picture resolution. This summer marked a major milestone in the journey towards 4K as a widely adopted standard: not only streaming UHD video on BBC iPlayer (the UK’s most popular streaming service) but also streaming it live. From two events. What could possibly go wrong?
A new blog from the BBC’s technology team gives us an idea of just how many things can and did go wrong, as iPlayer experimented with live UHD streaming – something it opened up to the public with the explicit label of being a test.
The first hurdle was not having any UHD capable OB vans in the UK – they are often busy providing sports coverage for BT Sport and Sky, so there were only a few events the BBC could test 4K streams for before the World Cup and Wimbledon, without publicising them. At the time, they had a couple of thousand viewers.
“We covered the FA Cup game between Southampton and West Brom (which I’ve now seen about fifty times), the Rugby League and some of the FA Cup final. By the end of this testing, we had a good feel for the workflow but we hadn’t put any significant load through the systems,” explains Senior Product Manager Jim Simmons.
That determined the bit rate for UHD averaged out at around 25Mb/s per viewer, allowing the BBC to calculate that its servers could handle a maximum number of around 60,000 concurrent UHD viewers – but with 2 million devices that might be capable of playing the UHD streams in the UK, the Beeb decided to make the streams available on a first come, first served basis.
All BBC One matches were made available in 4K for compatible TV sets with BBC iPlayer, kicking off with Urugay vs Egypt. (Trivia fans note: The first ever UHD World Cup goal on the BBC was scored by Gimenez for Uruguay in the 89th minute against Egypt on Friday 15th June.)
“There were some comments about stuttering and juddering and speech getting out of sync despite viewers having high speed internet,” admits Simmons, with further audio/video syncing issues plaguing the France v Australia game the next day.
Viewers took to Twitter to voice their complaints over the experience, while BBC engineers tweaked and tested behind the scenes to rebelance traffic, identify network errors and iron out any potential obstacles preventing the smooth service required for the high-demand UHD quality.
By the time the BBC One presenters told audience there was UHD available online later in the tournament, viewer numbers spiked 10,000 in a few seconds, notes Simmons highlighting just how much potential demand for 4K BBC TV there is.
After Wimbledon arrived to double the potential workload, the final weekend built up to both tennis and football finals on Sunday 15th July. These “ran smoothly” says Simmons.
A peak of 44,300 viewers saw Novak Djokovic and France win their respective tournaments, including the first penalty awarded with the help of VAR in a World Cup final.
“We don’t know if the VAR was in UHD or not,” he jokes.
The peak occured with England vs. Sweden on Saturday 7th June, with a 3pm kick off, which saw the BBC hits its cap of just over 60,000 concurrent 4K viewers halfway through the first half – a level that stayed constant until the final whistle.
“The UHD trial was a brilliant learning experience for us so we definitely consider it a success,” he concludes. “It’s clear there’s lots more to learn, work on and improve, and massive events like the World Cup and Wimbledon really put our systems through their paces. We hope those that watched it had a good experience, and sincerest apologies for when it didn’t go so well.”
The final result was a genuinely game-changing experience for viewers with 4K. Football in UHD is broadcast with such clarity that even zoomed out aerial shots capture each player crisply as they move around the pitch. Tennis is also quietly jaw-dropping in 4K, with the crowd in the background rendered in clean details. Both, particularly when combined with the HDR offered by BBC iPlayer, create a sense of depth to the images, with the players so clearly distinguished against their surroundings that it’s almost like watching in 3D.
Crucially, though, 4K has a lifespan beyond that briefly indulged novelty. Indeed, BBC iPlayer’s 4K test was set up in a way so that the improved system is still in place to be trialled again at the next available event.
“Live streaming Ultra HD over the internet is at a very early stage, but we’ve taken an important step with this trial,” adds Simmons. “We will continue to build our capability and make sure future audiences have a free-to-air option for live Ultra HD and HDR.”