LONDON, UK—BT Sport in the UK has delivered a couple of broadcast world’s firsts this year, beginning with the first live broadcast of Premier League football with 4K Ultra HD resolution video and Dolby Atmos audio at the end of January. At the beginning of June, BT Sport broadcast the UEFA Champions League Final live using High Dynamic Range (HDR), UHD and Dolby Atmos at a private screening in London.
The live broadcast of Dolby Atmos audio was far from being a one-off. Starting with that top-of-the-table match between Liverpool and Chelsea in January, the broadcaster has delivered an average of two soccer matches each week throughout this season in Dolby Atmos on its premium 4K UHD channel.
To those selected matches from the English Premier League, Champions League and FA Cup, BT Sport added another world’s first in April—live boxing coverage in UHD with Dolby Atmos. Fight Night Live, a partnership with dedicated channel BoxNation, plans to present 20 premium fights a year. And with the recent news that Sky Sports will be covering 124 matches from the English Premier League in Dolby Atmos this season, UK fans will have access to a large number of sports events produced in the immersive audio format.
Dolby Labs has taken a two-phase approach to next-gen audio, according to Rob France, the company’s senior product marketing manager. First, he says, “What can we do and make it available quickly and really easily in a backwards-compatible way? We came up with what we’ve done with Dolby Atmos, using Dolby Digital Plus.” Phase two will implement enhancements such as enhanced loudness control and accessibility options, via Dolby’s next-gen audio system, AC-4.
Ian Rosam, managing director and co-founder of the UK’s Video Sound Services, has taken broadcast audio production of the Premier League from mono in 1992 to Dolby Atmos today. “It’s interesting how little it has impacted the workflow,” he says.
“The key when we started was that we wanted a workflow where the supervisor or A1 didn’t need to do anything different on the console if they were mixing 5.1 or Dolby Atmos,” adds Richard Williams, audio guarantee for Telegenic, the outside broadcast production services provider who delivered many of the Dolby Atmos productions for BT Sport, including the Champions League final and the Fight Night Live boxing events.
There are currently three companies in the UK with Dolby Atmos-capable trucks, France reports. “Particularly in the UK, I don’t see another truck being built at the premium end without Dolby Atmos being in there,” he says.
The mixers still deliver separate stereo and 5.1 mixes (to satisfy international obligations) out of the truck over SDI. The Atmos mix is encoded into a Dolby ED2 stream that carries the object metadata along with the audio. That is transcoded to Dolby Digital Plus, then passes through Ericsson’s media and broadcast facility, which manages BT’s playout, and on to BT’s facilities for HEVC 4K encoding. The stream is sent to consumers via BT’s Infinity fiber broadband network.
All elements are treated as fixed objects, so mixing for Dolby Atmos has had little impact on the 10 or so A1s working these events, says Williams. “On the surface, they’re not doing anything different to what they were doing in December.”
Central to the transition has been the SoundField tetrahedral ambisonic microphone, the decoding processor for which has been updated to extract 10 outputs, including height information, from the single point source capsule. “It’s just a matter of using more desk resources, putting up another 4.0 mix and adding that into the data stream,” says Rosam.
SoundField mics, which generally provide the immersive mix bed for soccer and boxing, are permanently installed at many UK and European stadiums or can be rigged quickly on game day. The physical size and architecture of US stadiums may be a barrier to the easy adoption of such a microphone here, however. That said, France observes that events have been successfully produced in Dolby Atmos using existing microphone plans where there has been no possibility of rigging a single point source microphone. Hanging such a mic from the lighting truss above a boxing ring is easy enough, regardless of the venue.
Dolby Atmos, being object-based, offers the promise of alternate commentary tracks that could be selected by consumers. The Dolby Digital Plus delivery mechanism doesn’t support personalization, says France, but by setting up a workflow for BT Sport now and delivering that ability as far as the transmission encoding stage, the path has been laid for the next phase.
Regardless of the technicalities, don’t underestimate the power of immersive audio, says France: “We shouldn’t forget that all the passion of an event is carried in the audio. The greatest 4K HDR pictures will let you see what it looks like, but if you want consumers to experience what it’s like to be a fan of the team, and to be there, the only way you can do that is through the audio.”