Points of View and HD Picture Quality: a response
As there is no conspiracy around picture quality, and therefore no great revelation to make, I can only apologise to those of you who found my Points of View appearance a disappointment. But given the blog inches which have been devoted to the subject - and the challenges therefore for new joiners - I thought it might be helpful to set out clearly and at slightly greater length than is possible on air, the issues that are being debated.
The charge made by a number of you is that the substantial drop in bitrate for BBC HD since the channel was launched - and in particular the reduction in bitrate in August when new encoders were introduced - has had a "catastrophic" effect on the picture quality offered by the channel.
For those not in the know, it might help to clarify what bitrate is. Just like MP3 music, pictures can be broken down into digits or bits, and transmitted as a stream of information. The bitrate is the number of bits of information sent every second. This debate is to an extent about the impact that more bits per second has on quality. Those who believe that picture quality has deteriorated because of the drop in bitrate are of the view that picture quality is determined to a significant extent by the "speed" at which bits are transmitted. My view, and the view of the BBC HD team that works with me, is that picture quality is less to do with "speed" and more to do with the way the information is processed.
Now back to what has happened to date.
- When BBC HD launched as a trial service in June 2006 it was one of the first HD channels off the block. It used first generation systems with first version software, and used a bitrate of around 19Mbs. Consistent picture quality was a big issue even with a pretty limited range of content.
- By June 2007, new software delivered improvements to picture quality, and the bitrate reduced to around 16Mbs.
- By August of this year, the old hardware was reaching the end of its life and was no longer supported effectively. We therefore put new encoders into service, supported by new software. These encoders handle pictures differently from the old, and are able therefore to work with a lower bitrate of 9.7Mbs.
- The new encoders were tested in advance of being slotted into the BBC HD broadcasting chain. But that testing did not pick up problems with some very specific mixes and lighting changes. These issues became apparent very quickly during the broadcast of a Championship Football match on the channel. We acknowledged the problems, apologised, have put a temporary solution to the problem, and are testing a permanent one.
- There also appear to be some issues around picture "noise" - basically more fuzziness in what should be solid areas of pictures - which we have been seeing a bit more of since the encoder change. As far as we can tell, these are as a result of the "better" pictures now being transmitted to TV sets by the new encoders. Because the new technology conveys the picture information captured by cameras more comprehensively, for the first time we are seeing information that has been picked up but which was effectively "softened" by the system previously in place. We're obviously working on dealing with that too.
- But, with the exceptions I've outlined, in our view the new encoders are as we hoped delivering the same or better picture quality across the majority of programmes, the majority of the time.
We all need to accept that a great deal of our perception of HD picture quality is driven by our pre-conceptions. Some Dutch research published last month (the report I saw was from Informa, dated 28 Oct 09) highlights the extent to which views on picture quality are driven by expectation and emotion. On an HD TV, without an HD connection or receiver, some people will believe that they are watching HD pictures and believe they look substantially better than SD. I have no doubt that for those who believe the bitrate cut has killed picture quality, none of the changes to the encoders that we will make to address the problems which we know are there will make any difference, unless they go hand in hand with an announcement that we've upped the bitrate.
I hope what I have outlined makes clear there is no grand cover-up - and I know that the Head of Technology for BBC HD, Andy Quested, has plans to write at length on the testing that we have done and the detailed assessment that underpins the view that there is no decisive relationship between bitrate and picture quality. I hope it is also clear to everyone - regardless of where they sit in this debate - that it would be an act of extreme stupidity for the BBC deliberately to create an HD service which set no higher standards, and delivered no better picture quality, than its SD channels.
Picture quality, and beyond that the overall delivery of the channel, is of course of the utmost concern. But so too is ensuring that there are programmes available that people want to watch on BBC HD. At the moment we are airing around 40 hours of new content a week on BBC HD, a reflection of the extent to which the mainstream of BBC programming is moving across to the new technology. Sunday night sees the long-awaited arrival of Top Gear on BBC HD, in conjunction with its return to BBC Two. The coming weeks will also see the first ever Children in Need night in HD, and a broadcast of a special Children in Need concert. There's new contemporary comedy and drama, and we are going of course to be bringing you the last appearances of David Tennant as Doctor Who, and next year will see the arrival of Matt Smith as the new Doctor, and the first full series to be made in HD. Next year will also herald moves into HD for The Apprentice, and a number of other major series are also in discussion, alongside an emphasis through the year on some major science programming. The Christmas schedule will be out in the next couple of weeks - we're in the process of finalising it - but I can promise you that the vast majority of BBC treats will be in HD, and we will be offering extended broadcast hours through the holiday period.
I'm delighted that beyond the commentary here, more and more of you and your friends are finding and enjoying some of the new programmes that we're showing in HD. We will keep on extending the range - and managing the quality of what we do - and trying to organise those programmes as best we can for you while the BBC HD shelf gets progressively fuller.
Danielle Nagler is the Head of BBC HD, BBC Vision.