Dirac Algorithm Helps BBC Transport HD Olympic Coverage Via SD Circuits

By Kevin Hilton
SVG Europe correspondent

Long before the first starting gun is fired the Beijing Games has stirred up several controversies. While not on the same scale as China’s human rights record the number of people the BBC is taking to the Olympics has caused a considerable furore that just will not go away.

But the BBC prides itself on being at the heart of an event and says the 437 staff are necessary, 33 more than the Athens Games, because it is providing twice as much output as for those last Olympics. In bald figures the BBC will be producing 3,800 hours of footage, provided by 44 feeds supplied by Beijing Olympics Broadcasting (BOB).

Many of the 437 personnel will be working in 18 edit suites that are part of the BBC section of the International Broadcasting Centre (IBC) in Beijing, as well as production and ENG teams around the venues. To deal with the output from China there will be 16 logging stations at Television Centre (TVC) in west London, operated by personnel who must be wondering what they did wrong to not be considered for overseas travel.

Much is made of this being the first high definition and the BBC now has a dedicated outlet for the technology but as its HD Channel was not given the official go-ahead until November last year the broadcaster could not confirm to BOB that it would need suitably equipped connections for a number of its feeds.

This means that although the BBC intends to have a great amount of material in HD only SD circuits have been allocated. To get round this not inconsiderable obstacle the Dirac Pro compression technology will be used to carry HD footage over uncompressed SD connections. BBC Research & Development developed the system, with the codecs for contribution work designed and marketed by Numedia.

The Dirac image compression algorithm encodes footage using a motion compensation method and is implemented using Numedia’s Chameleon platform. Numedia was established in 2004 by former Snell & Wilcox engineer Stuart Sommerville; its range of Dirac products includes units for 1080p to 1080i compression, HD-SDI multiplexing and HD SDI to SD SDI compression.

HD is usually promoted as a pair with 5.1 surround sound and the BBC is certainly doing that for this Olympics. This, however, is perhaps even more of a challenge for the BBC, and other broadcasters, than the high definition video. Andy Quested, the principal technologist in charge of HD for the BBC, says the broadcaster will “try to do 5.1” where it can and has been in discussions with those organising the host feed.

“There may not be 5.1 or what is provided might be unusable,” he explains. “It could be too heavy on the effects or too wide or have too much commentary. We may have to go back to stereo because we have to have a balance between our own added audio and the raw feed.” There is the added complication of the Olympics being a massive event taking place over a relatively short period and comprising hugely complicated events happening at the same time.

BOB is distributing discrete 5.1 surround audio, plus stereo, embedded in the HD SDI signal with no Dolby encoded formats involved. Charlie Cope, a video editor with BBC Post Production, regards this as beneficial because there will be no expenditure on encoding and decoding but says the disadvantage is that much of the equipment being used has only eight audio tracks. If six of those are used for 5.1 then there is not much leeway for accommodating a stereo mix, which is necessary for editing and feeds taken by BBC News.

Like many broadcasters today the BBC now has many outlets within its organisation to consider on an event like the Olympics. As well as 300 hours to be split between BBC1 and BBC2 television there will be 2,450 hours through the interactive BBCi service. BBC Online, Radio, News, Nations and Regions and children’s service CBBC will also be taking footage from the Games.

New technology platforms will play a critical role in dealing with the seven hour time difference between China and the UK. Interactive, streamed video on broadband services and mobile platforms will give on-demand access to the Olympics, supporting the live prime time broadcasts. Footage for all this will be prepared at the IBC on Olympic Green in Beijing using a tapeless production system, mirroring the one that has been implemented within the BBC in recent years.

BBC Sport’s facility at the IBC has been planned with BBC Resources and project managed by the broadcaster’s technology partner Siemens IT Solutions and Services, which contracted Gearhouse Broadcast as systems integrator. The 1500 square metre area houses a control room for HD production and one for interactive internet and mobile phone services. These are supported by 18 edit rooms, production offices and two big servers, all of which are connected to the venues and the BOB EVS server.

This storage system, and accompanying logging software, is linked to the BBC’s EVS network, which in turn feeds an Avid ISIS server. With everything in data form, incoming material can be edited and prepared as it arrives, making for a quick turnaround. BOB will include simple metadata in the video and audio feeds, which BBC staff will be able to expand upon using the EVS IP Director media management program.

This will assist the logging operation, which will be carried out in London in an area at TVC housing 16 workstations. All editing and storage is to happen in Beijing and once feeds have been logged in London information is sent back to Beijing over IPTV circuits to update the local database. The BBCi and BBC Online crews will also be able use this data, with the London logging operation working through the night so there is no lapse caused by the time difference.

The BBC’s IBC facility and its studio in the futuristic glass Ling Long Pagoda will be run by staff from BBC Post Production and BBC Studios, with crew and equipment also provided by SIS Outside Broadcasts (formerly BBC OBs). SIS OBs has sent two HD trucks to China and these are sub-contracted to BOB to provide host facilities for coverage of sailing and rowing. The BBC itself is not using any scanners; instead, flyaway packs are being used at venues for the broadcaster’s unilateral coverage and presentation, supplementing the host feeds.

There is particular focus on events in which British competitors have a strong presence or a good chance of medals, including athletics, swimming, gymnastics, hockey and cycling. The biggest unilateral venue, for most broadcasters, not just the BBC, will be the National Stadium, where the opening and closing ceremonies and track and field events are being held.

This is a full HD outside broadcast installation, running with its own server for post-production. The BBC will also be able to broadcast live from another 13 venues, if the need arises. There will be editing facilities run by BBC Post Production at Qingdao for the sailing, Shunyi, where the rowing is taking place, and in Hong Kong, which is hosting the equestrian competition. These venues will also feature presentation areas and cameras for interviews.

Alongside the athletics tracks and at other sporting areas there are “mix zones”, offering three outputs for roving camera crews to plug into and connect to the main feeds. The intention is that these will be used mostly by teams working for the BBC’s Regions, Nations and News departments. The broadcaster has also worked with Team GB, the umbrella name for British competitors at the Games and the body representing them, to create a remotely controlled broadcast point. This allows athletes to walk into the centre, put on an earpiece and communicate with the IBC, where an operator will run the camera heads and microphones.

Eight ENG crews will be working around Beijing and venues in other cities, using Panasonic P2 camcorders. The BBC tried out the solid state format during 2006 at the Winter Olympics in Torino and the World Cup in Germany and has made it part of an overall move to tapeless production and post-production. For getting signals back to the IBC there will be BBC News SNG vans around the Chinese capital and at Team GB’s camp in Macau.

Satellite also plays a part in sending signals to TVC in London for transmission on BBC1, BBC2 and BBC HD but this is to provide a secure backup to the main digital fibre circuits. The EBU is providing over 200Mb/s of redundant international circuits to the BBC for its transmissions. These are arranged in several routes around the world between Beijing and the UK and will also accommodate voice and data links and the 16 channels of IP streaming for logging purposes.

The BBC is exploiting all the technology available to it and as many of its platforms as possible. As well as BBC1, BBC2, BBC HD, Radio Five Live, interactive channels and the internet the broadcaster is calling on a rather unlikely outlet to provide as much coverage as possible. The BBC Parliament channel on digital terrestrial platform Freeview will be used to “enhance” other transmissions but even the most die-hard government watcher cannot complain as the House of Commons will be in recess while the Games are on. But the politicians will probably be too busy coming up with new policies to be watching the Olympics. Maybe.