Changes in the air

The convergence of computing with communications technology gave us the Internet and shook the movie and music industries to the core. Now the convergence of computing and consumer electronics is about to do the same to broadcasting.

Digital broadcasts, which use less bandwidth than analogue, have already brought many more TV and radio channels, giving more choice but reducing per-programme audiences. Multimedia broadcasts of web-like content are in their infancy but could add a new dimension to the use of portable devices. And personal video recorders (PVRs) and media centre PCs, which facilitate recording and time-shifting, are changing the way we view TV.

Driving many of the changes has been the BBC, thanks partly to freedom from commercial restraints afforded by the licence fee. Notably it has one of the world's best websites. The first was set up experimentally by research leader Brandon Butterworth at the BBC's Research and Development Lab at Kingswood Warren, Surrey, in the face of some scepticism.

The BBC's online presence has since reached the point where it is compounding the challenges to traditional programming. It will be multicasting many events in the Olympics this year, which is expected to lead to more online coverage of events and add to the already bewildering choice of viewing. The BBC site enables time-shifting by providing access to some radio programmes up to a week after they are broadcast. The ultimate would be to offer access to the entire BBC archive - and, amazingly, this (or a near equivalent) is on the cards.

The BBC charter is under review and radical ideas are being thrown about. Michael Grade said shortly after being appointed BBC chairman this year that the public owns BBC content and should have access to it for non-commercial use.

He also pointed out that access would be limited by formidable problems over copyright and repeat fees. But the technical issues are already being assessed, as I found on a visit to the splendid Victorian neo-Gothic mansion that houses the Kingswood R&D labs, where the groundwork was done for many of the developments in UK broadcasting in the past 50 years.

Millions of gigabytes

BBC engineer Michael Sparks reckons the archive could be stored in 14petabytes (14 million gigabytes), which is not too much to stack on hard disks. Sparks estimates that at today's data densities they would occupy five to eight floors of London's Canary Wharf. With densities likely to increase by orders of magnitude, storage should not be a problem.

The existing content could be transferred, and reformatted if necessary, as part of the refresh cycle all such archives need. It would be a costly business, but Sparks pointed out: 'We need the archive anyway. The best way to think of it is not as a back-end store for streaming but as a way of modernising the archive.'

Sparks stresses that just because the labs are looking at the idea does not mean it will happen. He said: 'It's not our role to decide whether these things will happen... we have to be there to help the BBC make an informed decision.'

Storage is, of course, not the only technical issue. You need an infrastructure able to deliver the content. One possibility the labs are exploring as part of an EC-funded project called Share It, is to use rights-managed peer-to-peer networking. Instead of loading a server with a request for a file, you find someone else who has downloaded it and get it from them. Sparks raises another intriguing possibility. The main archive has to use a production-quality format, but with high compression it could be packed small enough to fit on a laptop or home server with the data densities of the near future.

This level of storage would not be needed with P2P, which makes the entire network your archive. It's an eerie prospect: what amounts to a national memory bank, spreading itself resiliently through homes and offices across the country.

A different way of watching
How metadata will transform the way we use TV. Part 2 of our special report on Kingswood Warren.

Open challenge on streaming
Free BBC codec could rival commercial streaming software. Part 3 of our special report.