Broadcast
BT is taking a huge step forward with the launch of Europe’s first dedicated UHD sport channel, but its aim of delivering it live over IP remains some way off.
BT’s Infinity fibre-optic broadband provides the bandwidth necessary to distribute 4K to the home, but for a couple of years at least, live production for BT’s new Sport Ultra HD channel will be in 3G-SDI, which splits the 4K stream into four circuits of HD over conventional copper wire.
“IP (internet protocol) live infrastructure is not yet ready,” says BT Sport chief operating officer Jamie Hindhaugh. “We are looking at IP and attributes like high dynamic range and frame rates, and how that integrates into 4K. Our focus is on being trailblazers and staying out in front. For years the talk about 4K was stilted; now we are doing it and I think technology will follow our lead.”
The broadcaster has trialled 4K production over the past 18 months. In turning R&D into a live deliverable, the critical factor was commissioning and building a scanner, in partnership with Timeline.
“To build a 4K truck ready for 2 August [in time for the channel’s debut FA Community Shield broadcast], IP was never going to be viable for this project. But the next 4K truck we build for BT will almost certainly be IP-based,” says Timeline managing director Daniel McDonnell.
Key parts of the kit are able to be tuned to IP, including a Snell Kahuna vision mixer and Sony 4300 2/3-inch systems cameras. “We’re fairly confident we’ll be able to upgrade to IP,” says McDonnell. “The Snell Sirius router enables us to process all the audio and shuffle it around in the way we’d want to in IP, but IP video switching is still developing.”
Moto GP app
BT needed a mobile facility that could work in native 4K and HD. “That gives us lots of opportunities around cross-capture,” says Hindhaugh. “Instead of bolting on a 4K production, we can shoot in 4K and down-res to HD. This is crucial to our long-term success. You don’t want a similar model to 3D, which required dual live event workflows.”
However, there will be a period of adjustment as production teams work out the best editorial and technical approach. For 4K, this broadly means using more wide shots and fewer cuts between cameras. “You can show the natural flow of the game as if you were in the stadium,” says Hindhaugh.
Such a change is too big a risk for BT’s weekly HD English Premier League action, so for this season at least, its EPL coverage will be largely separate HD and 4K productions. Hindhaugh calls it “a hybrid 1.5 truck model”. Some 4K cameras will be down-res-ed to HD, while some HD positions, such as specialised overhead, wireless touchline cameras and Imovix superslo-motion, are boosted to 4K.
“I don’t want to cheat the system or the viewer,” Hindhaugh says. “Where we show HD, we will make it clear on screen or in commentary.”
However, two rights holders have already given BT Sport permission to capture and transmit in 4K and downres to HD for the world feed.
Game-changing tech
In its first six months, BT Sport UHD will also cover Aviva Premiership rugby, PSA squash, the NBA Global Games from the O2 and the MotoGP from Silverstone. Action will be shot at 50 frames a second, with the ambition to achieve 100fps within two to three years. “50fps is already a gamechanger,” Hindhaugh says.
The live 4K signals will be sent to BT’s Stratford headquarters over BT fibre. Signal test is made on Tektronix waveform units, with footage viewable on Sony PVM-X300 4K monitors and passed to Ericsson Broadcast & Media Services for transmission.
“The increased bandwidth requirements of 4K mean choosing between the relatively clunky use of 3G-SDI bundles, looking towards higher bandwidth SDI [12G-SDI or above] or moving to high bandwidth ethernet technologies,” says Steve Plunkett, chief technology officer at Ericsson subsidiary Red Bee Media.
Post-production for 4K programming will work from material recorded to EVS XT3 4K servers. “The amount of media is huge and we need to view it in 4K,” says McDonnell. “That’s complicated because there isn’t a 4K viewer available for edit suites at the moment.”
Consequently, Timeline and BT are developing a bespoke asset management system to work in 4K: “EVS IP Director will be able to handle 4K but we’re not there yet and we need a solution quickly to allow us to manage the huge amount of assets.”
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