Almost immediately after BBC One HD was announced back in May, there was speculation on the DS forums about whether more high definition BBC channels would follow. ITV recently confirmed the launch of HD versions of ITV2, ITV3 and ITV4, but the commercial broadcaster used the opportunity to move into pay-TV services by exclusively making the channels available on Sky. Nagler said that the BBC is committed to moving its entire channel portfolio to HD, but the problem remains the available capacity on digital terrestrial television. As the BBC is funded by the licence fee, it must always make any new channels available free-to-air on the Freeview service.
"Capacity on DTT (Freeview) is quite constrained and I don't think the BBC will get another [HD] slot should it become available. So that's an issue around moving the whole channel portfolio into HD," she said. "Over time, HD will become just the way we make programmes and the way people consume television, so at some point in the future, the whole portfolio will move, but I think it will be quite a long transition. Given that the BBC believes HD is the next generation of television, it's important to us that we have HD channels, but those HD channels must be available free-to-air in the same way SD channels are."
A possible solution to the lack of capacity on Freeview HD would be transforming the existing BBC HD channel into a high definition simulcast of BBC Two. Nagler confirmed that the approach is a possibility, but it would come with some difficult tradeoffs. BBC HD currently aggregates HD programmes from all the BBC channels and even with BBC One HD up and running, it would still have to house content from BBC Two, BBC Three and BBC Four. Creating BBC Two HD would therefore leave HD content from the other two channels without a home.
"BBC HD has the benefit of being able to capture programmes from across the portfolio, but it has the disadvantage of having its own independent schedule that some viewers find difficult to navigate," Nagler said. "It will be easier when the BBC One HD content has its own home and there is less jockeying around for particular slots. It's not impossible that there will be a BBC Two HD in future but we would have to have a lot more programming in HD for that to feel like the right tradeoff. If, as expected, we only get two HD channels [on Freeview], we would have to figure what we do with BBC Three, BBC Four and Children's HD content that currently has a home on BBC HD. So it's not now and it's not next year, but it's possible that it will happen. But there are tradeoffs."
An option mooted to solve the problem of limited spectrum capacity on DTT is broadcasting over the internet. Usually referred to as IPTV, the technology enables broadcasters to stream TV channels over broadband, which drastically cuts the costs when compared with DTT carriage. Backed by the BBC, ITV, Channel 4, Channel 5, BT, TalkTalk and UK transmission operator Arqiva, YouView will aim to upgrade the Freeview and Freesat platforms to support video on-demand and internet services when it launches next year. Nagler said that YouView will most likely support some HD content over IP, but the average UK broadband speed of around 4Mbps is simply not good enough for streaming HD channels.
"Someone may solve that problem, new technology is coming along all the time and it may be possible to stream HD over IP, but at the moment it isn't. With YouView we are limited, what we can do you can do, but that constraint may not last forever," she said. "The HD channels have no value unless they are HD. There is no purpose in devaluing HD, it doesn't benefit viewers if they get a cheap and shoddy quality content. In our view, you can't stream HD over IP networks. People will buy connected TVs and they will get the ability to download HD content from things like iPlayer. So there will be other ways, but our priority is to ensure that the programmes we are making in HD can be watched in HD by as many people as possible. That will be a challenge, but we have no plans to put our channels behind a paywall just because they are in HD. They will always be free-to-air."
Last month, the BBC ran a trial of Super Hi-Vision, a technology developed by Japanese public service broadcaster NHK that delivers pictures 16 times sharper than normal HD. NHK worked with the BBC's R&D division to compress the massive video signals for Super Hi-Vision, as at full resolution the service transmits at a colossal 24Gbs, compared to around 16Mbps for normal HD. NHK hopes to start broadcasting in Super Hi-Vision by 2020, but Nagler said that it "doesn't strike me as a cheap technology to deliver", especially as no TV set currently exists that can fully support the 7680x4320 pixel signal.
The BBC also recently trialled 3D production technologies by filming an Argentinean tango for Strictly Come Dancing. The three-minute film will be shown at 3D cinemas and 3D TV retailers in November for the 2010 Children In Need campaign. The trials are also part of BBC plans to capture some of the London 2012 Games in Super Hi-Vision or 3D.
"I believe that when the Olympics was last in the UK [in 1948] the decision was made to do it in black and white when colour was nascent, meaning there was no colour archive. So there is a feeling that it's extra important to capture something in these technologies," said Nagler. "I don't think that a final decision has been made as the BBC does not have the final say on what cameras will be placed at the venues; that is held with the organising committee. It's a complicated organisational set up, but I think it would be worthwhile to do some live 3D, as it's quite possible to do."
Despite the 3D plans, Nagler said that she does not envisage a scenario where the BBC would follow Sky in launching a dedicated 3D channel. While she can "understand why Sky is doing this because of the business that they are", Nagler claimed that it's "not obvious that a 3D channel is the way to go". She believes that most 3D viewing is done by specific choice, such as buying a cinema ticket or renting a 3D movie, which is very different to a TV schedule.
"We are still learning but I think that 3D can enhance certain viewing experiences. I find it hard to imagine that in the next ten years everything will be made in 3D just because it can be," Nagler said. "My view is that it will be more of a VOD experience. I think if 3D and the Olympics happens, we would want to make that available to as many people as possible. Whereas HD will be available in most households by 2012, I don't think a huge number of people will have 3D. But the BBC would want to make sure the content was available for everyone who was interested. HD was about 20 years in development before it really became properly commercialised. So I feel pretty confident that HD is going to be around for quite a long time. But it's important that the BBC engages with these other things, even though we have a degree of scepticism about when they are going to become mainstream."