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The Hitchhiker's Guide to Encoding: The Salmon of Style (Or how programmes styles can change your view)

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Andy Quested Andy Quested | 09:00 UK time, Friday, 11 December 2009

Friday


Programme Styles

The last area to talk about is programme style and the techniques used by producers. The HD Channel is expanding the range of programmes made and transmitted in high definition all the time. As the number of programmes grows we are bound to show some that don't appeal to everyone in the audience, just as any multi-genre channel would. Similarly some of the techniques and styles used will not match some viewers' expectations of what is or is not HD.

Posts have suggested we are changing the bit rate depending on the programme because individuals have seen something they really like the look of while others have suggested programmes are up-converted when they don't like the look. Neither is true. The bit rate has been constant since the change in August and the amount of up-conversion (or non-HD) allowed is still 25%. There is though a correlation between comments posted and some of the production techniques used to make HD programmes.
Techniques that cause the most debate are:

  • Motion portrayal (using 25p or so called "Film Motion")
  • Depth of field or focus
  • Noise & Grain
  • Softness & Smear

Motion Portrayal - Many programmes are shot using a camera's 25p option i.e. film motion. Drama and Natural History moved to HD from film and wanted to keep the same look. Technically there is more detail in a progressive image than the equivalent interlace image. I have mentioned this before in several posts.

Temporal resolution describes the motion of a sequence i.e. the duration of each frame in a moving sequence and therefore how far an object moves between frames.

Spatial resolution describes the detail of the image and is about the content of a frame.
The BBC R&D white paper WHP169: High Frame-Rate Television gives a very interesting insight on the relationship between the two.

At the moment though we leave the decision about motion type to the Producer and Director of Photography of the programme but there are times when we do comment on the inappropriate choice of 25i or 25p.

train_aq.jpgCaption: These two images are from the white paper. They are frame grabs of a moving train shot at 300fps (bottom image) and translated to 50fps (top image).

It is worth reading the paper if you want to know how the detail you can see in an image is very much dependant on the frame rate - unless there is no movement. However we are not talking 25 to 50fps to make the difference in clarity you see here it's more like 25 to 300fps!

Depth of Field - Drama productions often use focus to move the point of interest in a frame. Programmes such as Cranford and Wallander also use feature film style cameras with a very small or shallow depth of field which allows the point of focus to play a major role in the story.

There have been many comments about HD being pin sharp and some people believe an HD image should be in focus from the nose of the person in close up to the trees on the horizon. I think many people would find that incredibly distracting and (as some of the posts lead me to believe) people would just be looking at the image quality not the programme. Focus is a very useful programme-making tool, and when used well it adds to the look and feel of a programme.

Noise & Grain - as the range of programmes on the channel increases, we get programmes that are deliberately made to look "dirty" either by style of shoot or during post production. This technique is often used in the cinema too. However if overdone for television it will stretch the encoder and cause unpredictable quality changes. Programmes that do this will usually fail a technical review.

Softness & Smear - some programme makers do not want extremely sharp images and choose to soften the picture either with lens filters or in post production. Both series of Criminal Justice for example used softening to create a very distinctive look. However if this is overdone it will significantly reduce the image resolution and can increase the amount of noise in the image. We do try to limit the amount of lens filtering programmes use but if extreme image softening is required, we encourage people to it in post production so that if the end result is unsatisfactory at least we can ask for it to be removed.

Motion blur (or smearing) is another matter. It usually occurs when the camera shutter is not set appropriately. A programme shot at 25p should use a shutter speed around 1/50th sec (or 180˚). If the shutter is not turned on or is set too long, the images will smear. This doesn't look very nice and we do try and stop people doing it. If the producer wants to add motion blur, again it is always better to do it in post production. Doing it in camera is usually fatal!

Last thoughts:
It has been a marathon blog and has taken me a long time to write! But there was a lot to go through and a lot to check before I published. Over the last six days I have covered most of the technical issues raised in the four key picture quality blogs. I hope it has answered the questions you've asked and laid to rest some of the rumour.

Running through the sections day by day

I decided audio is always forgotten or left 'till last so I put it right at the front. I covered the recent audio issues we've had and some of the measures put in place to prevent them happening again if at all possible. More programmes are being delivered in surround sound now and I hope some of the recommendations due from the EBU next year will give people more confidence to try it out.

There is one thing that does crop up from time to time that I need you to watch (or should that be, listen) out for. Very occasionally the 5.1/2.0 switching gets stuck. It works very well for months then for no apparent reason sticks in 5.1. This has no effect on the audio but it's annoying for anyone using the switch information go to the Pro Logic option on an AV amplifier. Please keep letting me know if you spot it though and which programme is affected.

On Monday and Tuesday I looked at the history of HD encoding on the channel and the EBU recommendations covering programme making and transmission decision we made when the channel started. We review these decisions regularly and changes are made as and when the technology allows us to so.

Wednesday's and Thursday's posts covered how the tests are set up and the much requested PSNR and expert viewing tests results. It is fairly clear now that the new encoder is a lot more efficient than the old and more importantly, capable of many further upgrades as the technology continues to develop.

There is no doubt this series will cause much comment and raise more questions about image quality and encoding generally. I will try and answer as many as I can but in the end we may have to admit we will never be able to satisfy all of you when it comes to what is or isn't high definition.


Andy Quested is Principal Technologist, HD, BBC Future Media and Technology.

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Comments

Page 1 of 14

  • Comment number 1.

    Thanks for all your efforts Andy, but this is where I expected we'd be at the end of the week.

    BBC HD RIP.

  • Comment number 2.

    Andy first off, can I just say what a fantastic week of blogs it has been. I am sure like many I have followed everyday, and while I may not have understood every detail, i found the whole thing readable and interesting.

    But to be very blunt, I dont care about bitrates, I dont care about CBR Vs. VBR all I do care about at the end of the day is why on my TV at home with the same settings as before BBCHD since August the quality has got poorer.

    I will join IanMac in his RIP BBCHD, it was good while it lasted.

  • Comment number 3.

    "Noise & Grain - However if overdone for television it will stretch the encoder and cause unpredictable quality changes. Programmes that do this will usually fail a technical review."

    Sorry, I had to laugh out loud when I read this. And please don't insult my intelligence by telling me I don't understand depth of field. I don't expect the whole scene to be pin sharp.

  • Comment number 4.

    Andy I have patiently read through all of your explanations regarding the why's and wherefore's of BBC HD picture quality, but most still seem to me like an excuse, sorry! You state here that we viewers expect to see the whole screen from foreground to background absolutely pin sharp, and then say that many would find it distracting. I can assure you that when BBC HD began, the picture quality WAS pin sharp, in focus from foreground to background and there is no way was this distracting.
    Its far more distracting to view now in my opinion. (and other viewers opinions as you are well aware.) Previously the person or focus of a shot 'stood out' almost in a 3D manner from the rest of the picture, so detailed and sharp was the norm.
    Now, most of it looks grainy, soft focused, etc, and I have noticed that when I view something in standard definition that was originally shot on HD cameras, it can now look as good as your HD channel!
    Surely that is all wrong.
    I bought Freesat entirely to watch HD. I love HD. Everything should be filmed, shot done in HD. Now I do not want to watch anything in SD. But....the fantastic pictures that were being produced by yourselves on your HD channel have definately deteriated since August.
    Weren't the directors using all these techniques before then?

    It used to be a joy to watch, now its not much improvement on a good standard definition picture, and as one who 'bought into HD' and absolutely adore it, its a shame.
    TG

  • Comment number 5.

    I just though I'd quote what the BBC HD website has to say.

    "HD gives you exceptionally clear, crisp pictures with vivid colours and up to five times more detail than standard definition."

    In conclusion I have to say

    BBC HD RIP.



  • Comment number 6.

    I'd also like to add

    BBC HD
    (2006-2008)
    R.I.P.

  • Comment number 7.


    Job done! Action point complete. Case closed.

    You can't seriously be proud of running an HD channel like this?

  • Comment number 8.

    Thanks for your efforts this week Andy.

    Picking up on today's blog, would you say that PQ issues on Gavin And Stacey (blurred motion) are purely down to problems with original camerawork, and that a higher bitrate would not eliminate ? If so, shouldn't the BBC have more control over minimum technical standards that programmes it is going to show and if there is an issue with the end quality perhaps elect not to broadcast such a programme on the HD channel.

  • Comment number 9.

    Totally the conclusion I expected, the argument is no further on than a week ago. I have a full HD Sky package, and a large Blu-ray collection, so I think I can judge what makes a good HD picture and I don't rely on the BBC for my HD entertainment. But the facts remain, BBC HD is a very poor relation to most other channels. I witnessed an interesting conversation in a Sony Centre a couple of months ago. The BBC HD preview was on most displays, and a salesman was desperately trying to engage a customer in the benefits of HD. The customer just could not see the benefit, but asked why the Tv at the front of the shop was so much better. Needless to say, this Tv was showing Sony's own HD demo (on Blu-ray I guess).

  • Comment number 10.

    In the light of nearly all the questions that have been asked pointedly not being answered, I feel I must join reluctantly in the general consensus of BBC HD RIP.

    However, given the RIP and the fact that it's still staggering along being transmitted and causing upset, perhaps it should be renamed as BBC HD: The Zombie Channel...

  • Comment number 11.

    Thank you, Andy, for a fascinating and very informative set of posts over the last few days.

    I, too, *think* that I have noticed a reduced overall picture quality on BBC HD in the last few months. I will admit, however, that this has only been since I have become aware of other peoples' criticisms, so I will acknowledge that my impressions may well not be accurate.

    The conclusion which I draw most strongly from your comments is that the technology - both in terms of the EBU standards/recommendations and the physical encoders - is still very much evolving and so I look forward to seeing improvements in the future.

  • Comment number 12.

    What a waste of time - we all knew the outcome of these blogs weeks ago so no disappointment there!

    We still have 8 direct questions that need answers.

    Shame that the BBC is at the bottom of the pile when it comes to HD quality and professionalism.

  • Comment number 13.

    I thought this was an interesting blog Andy, I'd love it you could do more of this more often. I agree though with some of the comments, I'm not entirely convinced.

    Of the HD stuff I've caught over the past week, last week's Gavin and Stacy wasn't that great, some parts were okay but other parts were blurry. I thought last week's Top Gear was better, even the SD clips appeared to be better.

    I see that Gavin and Stacy is now out on Bluray, I'm investing in a PS3 for Christmas so I'll probably get Gavin and Stacy on Bluray. I'd be interested to see how it compares. Okay I know the Bluray bit rate is MUCH higher than BBC HD, but if what the BBC appear to be saying is true about bitrates, I'd have thought it should look nearly identical with the blur that affected Gavin and Stacy on BBC HD.

    Rob

  • Comment number 14.

    Andy,

    I have no problem with "looks" being applied to programs.

    The problem is that these effects are often excessive and unecessary. Often straight 25i will do just fine. When a program is so processed it offers little over the SD version, then the HD channel becomes redundant.

    You also mention

    "Motion blur (or smearing) is another matter. If the shutter is not turned on or is set too long, the images will smear. This doesn't look very nice and we do try and stop people doing it"

    We have discussed this before, yet more programs seem to suffer from it. It is unacceptable and has no place in HD production. To be blunt you need to put something in the commissioning requirements if people are still supplying material like this.

  • Comment number 15.

    One other question Andy in light of the bad press the channel is getting in the media and how many in the industry are sitting back laughing at the joke the channel has become - does your professional pride not occasionally think 'what am i doing with such a lame duck?' - just a thought :)

  • Comment number 16.

    This blog mentions motion portayal and references the BBC white paper. But the BBC white paper says we need higher temporal resolution for the current spatial resolution of HD, not the 25p that is mostly used for BBC HD. The BBC white paper/BBC researches like Richard Salmon says we should have much higher fps not the lowest possible (25p=half the motion that has been used since SD PAL started). Surely there should at least be a balance between high and low temporal resolution if the BBC don't want to believe/act on what their researches are saying?

    "Wednesday's and Thursday's posts covered how the tests are set up and the much requested PSNR and expert viewing tests results. It is fairly clear now that the new encoder is a lot more efficient than the old and more importantly, capable of many further upgrades as the technology continues to develop."

    But where are the full viewer test results? I was expecting test results in a table for each of the different bitrates comparing old and new encoders. I expected the test results to show results (including viewer test results) for each different programme/test clip. And why weren't they done at a screen size to viewing distance that allows the viewers to see the full HD (1920x1080) resolution instead of viewing distances recommended for standard definition TV watching? Shouldn't the BBC be using full HD resolution (full HD cameras are available) as that is what many consumer TVs are? I expected the tests to show results for the different screen types, Plasma, LCD, CRT, though LCD in particular as the others, will hide compression artefacts. Also whether all TVs in the test were full HD. Didn't a recent (2009) EBU document say that it wasn't expected that there would be much further improvement in codecs?

    Basically I don't think the blog went into enough detail on how the viewer tests were done at all, how many independent people participated in the tests, and no table of results was given.

  • Comment number 17.

    OK Andy - you have given a'Summary' - so that's for you efforts here.

    But are there no 'conclusions' that you draw from all of this?

    My first 'conclusion' is that the above is all well and good but if your 'unwritten conclusion' is that this IS the standard we ( BBC HD) are happy to output - then my response is the quality falls short of 'Stunning HD' by some margin.

    I take on board your comments about style etc of 'fictional drama' but when 'non-fictonal' programmes look poor - what's the reason other than the codec can't cope at this fixed level on any 'more complex' part of the show.

    Will post more comments later.

    Cheers, daveac

  • Comment number 18.

    Andy,

    you say

    "Wednesday's and Thursday's posts covered how the tests are set up and the much requested PSNR and expert viewing tests results. It is fairly clear now that the new encoder is a lot more efficient than the old and more importantly, capable of many further upgrades as the technology continues to develop."

    Actually the PSNR results you posted regarding the football match with the gross mix/fade problem only showed that this is either:-

    1. a flawed testing methodolgy
    2. the results are being mis-interpreted
    3. the results are being selectively presented.

    You saying the median result was that the 0.2db better than the old encoder cannot be reconciled with the fact that we ALL saw gross blocking during the camera racking changes.

    Well, perhaps it can. It just says most of the time it's about equal to the old encoder on undemanding material. On demanding material, at the moment it simply isn't.

    Also, as these are just comparisons to the old encoder, who says the old encoder was adequate?

    Now post the PSNR results of the new encoder against the source material on the playout server.

    It would be also interesting to see the notes of the expert viewers when caomparing the source to the encoder output.

    Finally, can you give some comment on what our set top boxes are doing to the pictures. This is very relevant after all.

  • Comment number 19.

    Also by saying:-

    "and more importantly, capable of many further upgrades as the technology continues to develop."

    ...are you saying you intend to improve the PQ when upgrades for the encoder become available?

    If so, is that not saying that currently you think the PQ is currently deficient?

    Why would you need to improve the PQ if it is genuinely considered perfectly acceptable at the momement?

    BTW- having said all this, thanks for the blogs, they interesting and informative.

  • Comment number 20.

    The blog says "If the producer wants to add motion blur, again it is always better to do it in post production."

    To create accurate motion blur later for a 25p programme wouldn't it be better to shoot at a higher frame rate (eg. 50p or higher)?

  • Comment number 21.

    Lastly, I'd like to take you back to something Danielle Nagler herself said on her own blog on 24 September 2008:

    "A number of you have commented on the picture quality on Jonathan Ross. You're right - the show doesn't look as good at the moment in HD as we would like it to.

    There are still elements affecting picture quality along the broadcast chain that we are working on (and some of these don't just relate to Jonathan Ross). I hope that, as we address them, the picture quality will improve across the channel."

    Over a year on now and we're still waiting Danielle....

  • Comment number 22.

    I find it extremely perplexing that in the audio section Andy DID mention specific programmes and instances where blog posters had flagged problems, but other than a passing mention of Criminal Justice none of the extensive list of programming that has been discussed, screen grabbed etc. by concerned licence fee payers has been given the same detailed explanation.

    This may have been a marathon blog for Andy Quested but it so very much less than the combined effort put in by numerous posters within these blogs, let alone the combined expenditure in equipment to which the BBC is sending a signal which is by many perceived to be below the standard which had been sent and below the standard that other broadcasters are still sending.

    Are we to take it from the lack of any meaningful discussion about individual programmes that Andy Quested and the rest of the technical team are telling us that the poor quality of Garrows Law etc. is an example of meeting or surpassing other channels.

    If so I find that utterly unacceptable.

  • Comment number 23.

    Andy,

    Thank you for a very interesting series of 'lectures' on TV program production and delivery. In that respect it was excellent.

    I have just 3 comments to make.

    1) Whereas you confirmed and discussed openly, the audio issues that have been experienced on the BBC HD channel and what was being done to correct them, sadly that wasn't the case with the picture quality issues. Not once was the deterioration in PQ acknowledged. It was neatly sidestepped at every turn and the overwhelming evidence presented that demonstrates that deterioration, was 'rubbished' at every opportunity.

    2) The telling questions (now up to 9 or is it 10) still have not been answered specifically. If that was because they were outside of your remit, then we would have appreciated being told that. We were continually being told to wait until all the 5 blogs had been posted, giving the clear impression that somewhere in the blogs, the questions would be answered.

    3) The BBC in general and the HD team in particular have let the viewing audience down by the continual denials that there hasn't been any deterioration in picture quality. As a result, they have also painfully witnessed, along with us, the press airing these picture quality issues around the world. This could have been contained if managed differently. I wonder whether the BBC, on reflection, are now regretting the way this situation has been (mis-)handled.

    May I also add my last respects to the demise of BBC HD

    "We saw you at your best, we were there to support you through your troubles. We will miss you"

  • Comment number 24.

    Andy Quested is obviously going to completely ignore the reality, which is the real deterioration in the picture quality, which we all can see.
    He also says "it is fairly clear now that the new encoder is a lot more efficient than the old". Very odd then that the PQ is now so much worse.
    So, Ray Mears, Garrows Law and Gavin & Stacey all look fine then? Who are you kidding?

    As others have said, until you sort it out, BBC HD R.I.P.

  • Comment number 25.

    Re my comments re the different way that Audio and Picture issues have been approached here. Maybe I'm being unkind but the audio issues can be attributed to an individual person, system or equipment error, whereas the PQ issues are more departmental, corporate and political in nature. So face saving over-rides meaningful discussion.

  • Comment number 26.

    Firstly, many thanks to AndyQ for taking the time to both produce and respond to this series of blogs which have been interesting and informative.

    Since AndyQ admits the HD Channel has a broad range of programmes, using a variety of 'styles and the techniques', one may wonder why the bitrate remains fixed on satellite, whereas other broadcaters use a variable bitrate upto 18mbps to ensure demanding matierial is handled effectivly. Indeed, even the BBC as part of Freeview HD will use statmux'd, and BBCHD outside the UK use much higher bitrate.

    Nevetheless, in responce to the latest blog from AndyQ, were it simply down to the various styles and techniques adopted by the programme makers I, and I believe, most of the people here would not be complaining about picture quality. As an example, I believe most viewers are used to, and can appreciate, the atistic merits of 'depth of field' where it often adds to the drama and even highlights the visual delight of High Definition.

    I am, however, not aware of any sudden and dramatic adpoption of these new 'styles and the techniques', since August 2009, therefore why would it be people were not arguing against such production techniques, (in large numbers), prior to August 2009, and why are people claiming to see an obviously detrimental quality of broadcast picture on the same programmes shown after August 2009 compared to before then.

    Whilst the series of blogs from AndyQ has been interesting, I have to say it moves the discussion more into the realms as decribed recently by Emma Scott, Managing Director of Freesat, as 'a bit of a geek issue', which for most here it most certainly is not.

    The sheer delight of watching BBC HD, enjoyed by the fortunate few prior to August 2009, has now being seriously dissipated.

    The statements from Danielle Nagler, Head of BBC HD, that there is 'no evidence that reducing the bitrate has an impact on quality', Emma Scott, Managing Director of Freesat, that "I think it's a bit of a geek issue, if I'm honest. I don't think that regular punters really recognise a recognisable dip", and AndyQs "we will never be able to satisfy all of you when it comes to what is or isn't high definition", leave me believing there is very little point in further engaging in these blogs as the mindset appears to be, much like the bitrate, fixed at a lower than required level.

  • Comment number 27.

    It's obvious from the above quotations that the BBC is seeking to marginalise our opinions. We hold the BBC to its mandate of meeting or exceeding the quality of other HD channels and at the moment BBC HD is one of the worst technically.

    This series of blogs while interesting and informative have done nothing to answer the direct questions we have posed. Evidence, as has been mentioned in other comments, has obviously been presented selectively.

    We brought into the World the BBC Zombie Channel.

    RIP Our true public HD service.

  • Comment number 28.

    Just as i expected we no closer to the knowing why BBC have cut the bitrate and how they can really believe the current levels are acceptable. This is another complaint about Gavin & Stacey as well Mitchell & Webb both had lots of motion blur and lack of sharpness.
    I do hope that the BBC trust find that BBC HD is wrong and is not giving the license fee payers good value for money for a HD channel, in case of this I know some viewers are also exploring another area of complaint through Ofcom as they believe that BBC HD is not sticking to the conditions of the licesnse that they were granted as they stated that they would provide an industry leading service

  • Comment number 29.

    Andy - thanks for the very interesting blogs over the past week or so. They have provided, as I've said before, a good insight into the makeup of the HD testing process.

    The problem is, we're no further forward than this time last week - in fact with the national press now highlighting the issue, I would say you've gone several paces backwards.

    PQ has deteriorated in so many people's opinions and in comparison to other HD channels that surely this can not just be ignored or put down to the style of the producer. If that was the case, why are there so many examples being given of the varying quality of the picture but in the same program! Surely that straight away makes your style argument a bit of a non starter.

    Other HD channels show a variety of output which I watch a lot of and I can assure you that the BBC HD channel has the worst overall PQ. Yes, I know things don't need to be pin sharp and the whole shot from foreground to background be in focus. However, I would expect the parts in focus to be pin sharp, vibrant and showing up to 4 to 5 times the increase in quality that HD should give (and let us not forget, exactly what the BBCHD website tells us!). Other channels do this - the difference between Sky1 and Sky1HD is substantial. The difference on Sky Sports and Sky Sports HD is as clear as night and day. BBC SD vs BBCHD - nope, idenitifiable maybe, but that's all.

    I think the BBC is a fantastic institution above all else. You provide high quality output across all forms of media which, for the £12 a month license fee, is something I am very proud of being able to have. However, the reputation of this area is now very tarnished indeed. The press are going to have another BBC bashing on their hands I fear, and yet it could all have been avoided so easily by answering the questions that are being posed directly and people not skirting the issues or trying to make us believe that what we are seeing with our own eyes is a myth.

    I know its Christmas, but the BBCHD management are turning into the equivalent of a baddie in a panto (you can hear the "oh no it isn't" against the "oh yes it is" phrases coming loud and clear). At least I now know why the BBCHD channel is not promoted on other channels - in its present state, I wouldn't want to be shouting from the rooftops about it.

    As others have said, BBCHD RIP - someone needs to resurrect it and quickly.

  • Comment number 30.

    I've deliberately not joined in this prolonged discussion about HD quality reduction, but have been reading most of the comments for the last 2/3 months.

    Whilst all of the posts Mr Quested has written are interesting, they fail to answer what I and almost all of the posters on here over the past months can see with their own eyes (mine included).... the HD quality reduced when the new encoders and bitrates applied. I object to being effectively told that my eyes are somehow defective, and what I see post encoder and bitrate change is no worse, if not better, than prevailed before the change... it is in my view patently not true, and my view seems to be echoed by virtually ALL of the bloggers here.

    As my profile name implies, I am an ex BBC engineer, and like to think that whilst my technical and theoretical days of modern techonology is out of date, I do have an fairly good idea of what is or is not a perceived change in quality visually. The likes of Ms Scott of Freesat who implies that I must be a 'geek' to actually SEE the difference in quality is patronising in the least, and offensive to most. I do hope that you, Mr Quested, if you get the chance (and you say you will if you do) take her and anybody else up on that most ignorant of comments.

    I have had Freesat HD for over 9 months, and KNOW the quality has deteriorated... and it is about time the BBC did not bury its head in the sands about this, and admit to it. The 8 questions asked by others are very pertinent, and it does not take a genius to wonder why they have been patently ignored by Mr Quested.

    Like others, if we are being effectively told that this is the quality that we have to accept now, then have the honesty to say so, and why, and justify that by answering the 8 questions.

  • Comment number 31.

    To think that I waited 4 months for this.

    Strange how the Daily Mail just needs to break wind and the BBC is grovelling in apology for perceived misdeeds when they should actually find a backbone. Yet when a swathe of their loyal users and, if you are like me, staunchest supporters point out an undeniable drop in picture quality then they suddenly find the strength to ignore us. Instead we get a 5 day excercise in semantics whilst avoiding the actual facts. As a photographer I can understand the effects of DoF and lighting but this doesn't explain or justify the large drop in quality.

    When I first bought a large screen LCD my main fear was that I would get blurring in sports like football, luckily my fears were unfounded and everything was perfect especially the stunning quality of BBCHD. Imagine my dissapointment when the first noticeable blurring came a year and a half later when watching Gavin and Stacey in HD. After shelling out £350 on Freesat and installation I feel somewhat cheated that the goalposts have now been moved and you have reduced the quality to a levelI don't find acceptable. I also feel sorry for Humax who have lost 3 guaranteed sales of their HDR Freesat boxes just to members of my family, this Christmas, who after coming and checking out the BBCHD quality last week (Gavin and Stacey again I'm afraid) have decided, after being blown away earlier in the year, that it isn't good enough to justify the outlay. Likewise with Humax new £170 Freeview HD box being announced, I will be giving that a miss as the quality of the HD again will not justify it.

    I can't believe 3 years ago I received relatively pin sharp analogue Tv and excellent FM Radio. Now I have a Freesat set up and 3 DAB radios and I actually feel worse off.

    Please show some dignity and offer your viewers some answers to the questions listed elsewhere in this blog instead of hiding behind science.

  • Comment number 32.

    They're not going to admit anything because too many people would lose too much face and people might start wondering if they're worth their six figure salaries (plus expenses).
    BBC HD RIP

  • Comment number 33.

    I agree with #9 Mark Jones; I also no longer rely on BBC HD for entertainment on television.

    The Bill on ITV1 HD last night was marvellous!

  • Comment number 34.

    Danielle, Andy - here are the 11 questions we want answers to incase they have been forgotten:

    1.Why was the higher bit-rate not sustainable?

    2. Why can't we have a short period back on the higher bit-rate as a simple test?

    3. Why can't the satellite transmissions be statistically multiplexed to make better use of the available bandwidth on the transponder?

    4. Why is BBC HD being transmitted in Scandinavia at a higher resolution and a higher bit-rate than that being transmitted to the licence paying public in the UK?

    5. Will the BBC be increasing the bitrate in the near future? Yes?No

    6. Will the BBC be changing the picture format to 1920x1020? Yes/No

    7. Will the BBC be introducing a variable bitrate? Yes/No

    8. What happened to picture quality when you tested higher bitrates on the new encoder?

    9. Why is the BBC transmitting a identical copy to HD on the same transponder CH 6945 what is the point of that?

    10. Were tests carried out at many different bitrates to determine which would be used?

    11. How did you decide on the new bitrate and why was it chosen?

  • Comment number 35.

    Would somebody please confirm or deny if this supposed quality change has affected Virgin Media's MPEG2 service on cable, or if it's merely limited to the MPEG4 sat version?

  • Comment number 36.

    To my eyes, it's the same degraded service on Virgin Media. I ran a poll on my blog (www.vmhd.blogspot.com) and of the 278 respondents 83% thought the picture on BBC HD had deteriorated recently. We do have the option of watching some HD programming on BBC iPlayer on Virgin - I haven't done any comparisons between the on demand version with the "live" broadcast.

  • Comment number 37.

    Danielle Nagler speaks to What Satellite (wotsat), predictable denies PQ issues:

    http://blog.wotsat.com/page/whatsat?entry=bbc_hd_boss_sticks_up

    Friday December 11, 2009
    BBC HD boss sticks up for picture quality

    The fuss over BBC HD’s picture quality has made it as far as the newspapers now, with the Telegraph and (predictably) the Daily Mail wading in to hammer the BBC over whether the channel’s putting out sub-par “fuzzy” broadcasts.
    The BBC’s Andy Quested, meanwhile, has been defending the channel’s position on the BBC Internet Blog (starting with this post). Wotsat recently spoke to Danielle Nagler, Head of BBC HD, who was keen to defend the channel’s broadcast picture quality: “There is a very vocal group of people who believe that the picture quality on BBC HD has gone down over time,” she said, “and that that is due to the reduction in broadcast bitrate for the channel over time. I think we’ve been very clear that the broadcast bitrate has been reduced; we believe that there is no direct correlation between a drop-off in picture quality and that reduction in bitrate. We’ve been able to reduce the bitrate because of advances in technology.”


    She also points to differences in filming style and cinematography as being a cause of many complaints. “I think when you look in detail – and I have looked in detail – at the complaints that are being made, and the programmes that are being cited, quite a lot of the issues that are being aired around picture quality are about what I would call styles of HD,” she notes. “That’s not by the way to dismiss the complaints, because the people that make the complaints do genuinely believe that the picture quality on our channel is not as good as it was or as they believe it should be.”

    “Film-look” versus “sharp, crisp line”
    Nagler’s suggestion is that viewers are mistaking one kind of HD shooting style – the “clean” HD used for news broadcast – as the ne plus ultra of HD picture quality, and that dramas shouldn’t be judged by that standard, as they’re aiming for a “film-look” shooting style. “When there is a big discussion around a programme like Criminal Justice, and complaints about the picture quality there,” she explains, ”I think it becomes clear that some of those complaints are about the film-look that we quite often use on BBC drama, where you don’t get what some people see as the typical characteristics of HD – that very sharp, very crisp line, which is what to them is HD picture quality.


    "That is part of HD," she continues, "but actually what we do is encourage a whole lot of different looks which producers and directors will use as they see fit. And the look of a programme like Criminal Justice, which uses HD in a much softer way, which quite often shifts focus so that you get a kind of blurred background, is not bad HD and is not bad picture quality on the HD channel. It’s a creative choice to use HD to give a feature-film look to drama. And I think that’s an important distinction.”

    “The other thing I would say is we broadcast a very wide range of material,” she adds, “and that material brings a whole lot of different looks and feels of HD with it, in the same way that our standard definition programmes have a lot of different looks and feels to them. I think it would be absolutely wrong for us to say, “HD picture quality is purely about one thing that you can do with the technology.” What we’re aiming to do is to explore it creatively and to use it to bring better pictures across the board to HD. I appreciate that that is not to everyone’s taste; some people have a very very clear view of what they want HD to be, but I don’t think that’s what we’re trying to achieve.”

    Working with new technology

    Nagler also stresses that the BBC is still experimenting with HD, and that, inevitably, some experiments will be more successful than others. “I have looked at it, and I am continuing to look at it; I am not persuaded that there are issues across the board in relation to our picture quality,” she says. “I would be the first person to say that of course there are some programmes which don’t work as well as we would like them to do; that’s in the nature of moving programmes to HD and getting people used to working with new technology. But we do test – we put every programme that’s delivered in HD through a testing system to look at the HD content of the programme, and to look at the quality. And we will send programmes back – we do have debates about those programmes, and we do occasionally have issues on transmission, whether it’s around sound or picture – which we acknowledge. I don’t think there is a problem across the board in relation to the bitrate at which we broadcast and a drop-off in picture quality across the board. But I recognise that there are people who believe that that is the case.”

  • Comment number 38.

    Re: 37 above - "...But we do test – we put every programme that’s delivered in HD through a testing system to look at the HD content of the programme, and to look at the quality. And we will send programmes back..."

    Danielle/Andy - Why hasn't the current series of 'Gavin and Stacy' been sent back?

    Re: 35 above - "4. Why is BBC HD being transmitted in Scandinavia at a higher resolution and a higher bit-rate than that being transmitted to the licence paying public in the UK?" - EXCELLENT question - can you tune this channel in on a UK Sky HD box?

  • Comment number 39.

    EXCELLENT question - can you tune this channel in on a UK Sky HD box?


    No, not with the standrd equipment and dish.

  • Comment number 40.

    39... Drat! Thanks anyway!

  • Comment number 41.

    Have any tests been done with the new encoder at 720p/50?

    There would be some resolution loss, 12.5% horizontal & 33% vertical I think, but as we seem to get a softer picture now than before using the new encoder this might not make much difference?

    The real improvement would be motion handling provided the program was recorded at 50p.

  • Comment number 42.

    In reply to Midzone1:

    9. Why is the BBC transmitting a identical copy to HD on the same transponder CH 6945 what is the point of that?

    6945 is only another 'pointer' to the same bitstream. No bitrate is being wasted!

    Only 10 questions to answer now ...

  • Comment number 43.

    Well what a pointless exersize todays posting was. We have for months made it clear that the problems we see are NOT related to programme styles. Many of us have Sky and Blu-ray to show us the difference between high quality HD and the trash BBC HD is delivering. Some of us have HD camcorders which turn out better pictures than anything now seen on BBC HD.

    As for the other blogs in this series what a disapointment. The word that sums it up for me is SPIN. Why on earth did it take three months to produce this stuff. It is also clear that the BBC went about testing in a very amaturist way. All the EBU tests of HD picture quality tests I have seen include tests at the 3h viewing distance. The human eye only resolves 859 lines at the 4h distance the BBC used unless they were using binoculars. The BBC will be telling us next that we should be viewing out screens at 20 feet so we can see fantastic pictures. There are lots of other critisisms of the subjective testing. For instance as Dr Hoffmann of the EBU points out it is better mount the dispays virtically so that the viewer is equidistant from each screen.

    As for the PSNR testing we are presented with 2 graphs that don't even have the horizontal scale anotated. It is not realy clear what they were measuring was it was an average for all clips?. In fact I find these graphs realy dubious as they seem to show that both the new and old encoder are very poor. Another point is why include the playout server. HDCAM SR uses MPEG4 Part 2 Simple Studio Profile. So the reference clip is converted from MPEG4 to MPEG2 and then decoded by calcPSNR. The test stream is decoded by a profesional decoder. It would have been much better to convert the reference clip onto an uncompressed file. This uncompressed file could then be fed through the encoder/decoder to produce an uncompressed test file. The two uncompressed files could then be compared with calcPSNR. What I am getting at here is to minimise the number of variables.

    One thing that these blogs have revealed is a rather unproffesional approach to testing which has led to the disaster which we now see. Unlike some I don't think it is too late for the BBC to sort this but they will have to act soon. Dissatisfaction is increasing and the national newspapers are begining to sense blood.

  • Comment number 44.

    Posters and lurkers might like to read another BBC webpage - the the Technology section of the BBC Newsite:-

    'Most of the UK missing out on HD'

    http://news.bbc.co.uk/1/hi/technology/8407690.stm

    Liked this Quote they include:-
    "Unless you're really into your technology, perhaps you don't realise that just because it says HD on the box, the picture quality isn't necessarily HD," said Stuart Miles, editor of technology website Pocket Lint.

    Well BBC HD -does it say 'in stunning HD' on your box?

    Because my box (TV) only shows 'stunning HD when I play a Blu-ray film!

    Cheers, daveac

  • Comment number 45.

    “Theotherthingthing ouldsayie broadcaeryderyd materialsheand tteriarings wholelotifferent looksa"

    This is a red herring, I'm all for different looks but when the encoder makes them so ugly with macroblocking the whole intent is lost - just like the quote above when mangled to illegibility by blocking and bad prediction.

  • Comment number 46.

    Well there we go the last of the smoke and mirrors, what else did we expect. I know I did not expect anything other than this. The "apparant" poor PQ is all down to program styles what a laugh. Now we really do know what it is like to be run over with a massive unthinking bulldozer. No two way dialogue here, thats what you are going to get so you can lump it. I would not mind so much if Andy would just admit they have a problem at least then we could move on.
    Can I add my my RIP BBC HD I guess as I said in previous posts we should resign ouselves to having one less HD channel. At least I am not paying for it.

    It really is criminal and I am completely speechless I just hope the media latch on to the situation in a big way the BBC deserve all the bad publicity they get. I for one will not be recommending anyone to waste their money on Freesat

    Mike

  • Comment number 47.

    It would be very interesting to see if someone could get hold of a copy of the new Gavin & Stacey series on blu-ray and see if it's as bad as the transmission.

  • Comment number 48.

    Then they will blame your HDMI lead, you need one of these bad boys!

    http://www.highdefdigest.com/news/show/Wireworld/Wireworld_Reveals_$1,000_Platinum_Starlight_HDMI_1.4_Cable_/3896

    coming soon to currys for £1999.99

  • Comment number 49.

    @36/Neil

    What's curious about the Virgin situation is that, from what I've been able to gather from various discussions on the web, Virgin do seem to broadcast in full 1920x1080, albeit MPEG2, but there doesn't appear to have been this supposed 40% drop in bitrate, which was why I was curious how Virgin's feed is delivered. Is their MPEG2 version a re-encode of the MPEG4 stream, or is it a dedicated stream, which would not have been affected by the encoder changes for the sat version? If it's the latter, that would possibly discredit most of the complaints coming from the cable side of this discussion. Not that I'd necessarily want to do that, it would just be nice to know the facts. We do seem to have some very knowledgeable people around here. Surely someone must know the answer to this?

  • Comment number 50.

    Story now taken up by Sky News.

    Link to article here

  • Comment number 51.

    Great blog Andy Q thank you.
    I made a point in one of the others that I liked the way you had structured the blogs and replied to the commnets as they were being posted.

    You now have a core of less than a dozen questions repeatedly asked, and outstanding, some of which are only being asked as yes/no questions so I hope this final blog will see at least an attempt to answer these questions before the subject is closed.

  • Comment number 52.

    BBC HD PQ 6Gtn

    Thank you Andy for taking the time to compile the series of posts this week.
    They have been interesting on several levels.
    As a BBC supporter it has been a sad experience to see the obvious discontent of the public and the loss of respect which the BBC HD organisation had enjoyed.
    A situation with no winners and an increasing PR embarassment.
    It takes a brave man to stand up and deliver the bad news - which appears to be-
    the PQ will stay as it is or may improve with maturing encoder development.

    Having said that it is petty not to have the grace to reply to the 8 pertinent
    questions raised or to acknowledge them at all.

    A great deal of work must have gone into setting up the HD channel, I really don't want to come to this blog and complain, I would far rather be enjoying
    The HD as it was before August.

    Thinking about your PSNR charts and how very similar the old and new encoder results are leads me to the conclusion that this is what has happened :

    operate encoder at 16 MB/s then conduct a series of psnr measurements at progressively lower bitrates untill you find a bitrate (9.7MB/S) where the two
    graphs look near identical. 9 would have given a worse picture 12 would have been wasting bitrate.... If thats how you did it then I think you've "thrown the baby out with the bathwater" as they used to say.

    It's an oppertunity missed in my opinion- you could have used your excellent new encoders at 12MB/s and improved our PQ whilst saving Bitrate from 16MB/s. and as the encoders improved reduced the bitrate when appropriate.

    It seems to me that the chasing down of bitrate is an obsession when the real reason for having the HD channel at all is- High Definition- end of.

    I have posted on this blog because that is the one place where I can make my feelings known. Now it appears that as the BBC are unwilling to act on the requests of viewers to restore PQ then other avenues will have to be explored.

    The viewing public has the right to expect what we were promised- 5 times the PQ of SD. other providers manage it, you still have not explained why you cannot.

    My own conclusion is that this is not a technical issue, or a financial one but it is a political issue- with BBC deciding to ease off competing with others on the same platform and risks the BBC becoming a follower and not the leader in television Broadcasting

  • Comment number 53.

    #50: Unfortunately they perpetuate the false claim that blogs have been taken off line. Now the story is that the BBC have backed down and restored them! Journalists, eh? I think Nick Reynolds will be having a busy weekend at this rate.

    Wasn't this all very avoidable?

  • Comment number 54.

    I've just enjoyed River Monsters - Alligator Gar & thought the PQ excellent, vibrant colour & sharp, good field depth, no hideous soft focus.

    Of course that was ITV HD...

  • Comment number 55.

    The way I see it, surely the BBC aren't using encoder technology unavailable to Sky? The two companies must be using roughly the same equipment.

    Assuming that to be roughly correct, surely this tells us everything we need to know :-

    http://linowsat.de/hdtv/hdtv/hdtv.shtml

    There is a shocking disparity between bit rates, very few fixed bit rate channels. BBCHD appears to be only beaten in the budget bandwidth stakes by LuxeHD!

    Most surprising is how they can claim to offer FIVE times the quality on BBC HD to SD? Yes I appreciate there is a difference in encoders and all of the other sorcery we have read about this week . . . but seriously!

    To my, rather naive eyes, if the BBC were using some fantasic, magical, low bit rate, same PQ encoders, surely Sky would be all over them in a heartbeat?

  • Comment number 56.

    Disappointing opportunism for Sky to use this to plug their supposed 15mbit broadcasts and not mention 5 pages worth of very extensive technical explanations by the BBC, where Sky in a similar situation would undoubtedly just have copy/pasted their 15mbit claim as "evidence" and called it a day.

  • Comment number 57.

    As an experiment why don't the BBC just up the bit rate over Christmas - it will either prove us right or shut us up once and for all.

    Are going to take the challenge Ms Nagler?

  • Comment number 58.

    Just an observation.

    Every single day we have had atleast a couple of replys in each blog post.

    Today we have had none what so ever.

    Does this mean that as far as the BBC is concerned this matter is now finished and it wont be discussed anymore?


  • Comment number 59.

    More likely they HD department are creating the next bit of spin now that the press and SKY are on their backs!

    We still have all those questions above :)

  • Comment number 60.

    cletusvandamme#49,

    I am under the impression, I am sure Andy has stated this in a previous blog somewhere, that Virgin is fed seperately with an HDSDI feed. Virgin then perform mpeg2 encoding themselves.

    So AFAIK the new sat encoders are not relevant.

    I haven't seen BBCHD on virgin, but if people are convinced there is a drop in PQ, then it could be down to something else, be it imagination ;-) or misinterperating poor production with a PQ issue or something else in the broadcast chain.

  • Comment number 61.

    Andy may like to confirm/clarufy the above, but I suspect ge has put his tin hat on and headed for cover! :-)

  • Comment number 62.

    May I draw your attention to a BBC Story.

    Most of the UK missing out on HD (link here)

    Sarcasm mode:- I know exactly how they feel.

  • Comment number 63.

    AndyQ: Thanks for the series of blogs. I think I understand what you have presented.

    Please answer the following questions for me:

    1. Why was the previous bit-rate unsustainable?
    2. Given the extensive trials BBC did before launching, why was there no trial of the new encoders and the reduced bit-rates?
    3. My eyes have not changed nor my HD equipment, so why have you and DN persisted with the view that the reduction in HD PQ we noticed and reported via Blogs, Technical Fault Feedback and Formal complaints procedures; is not backed up with BBC HD technical measurements or your and your team not seeing any degradation.
    4. Why are some programmes producing good PQ, especially live state occasion broadcasts?
    5. Why can you not do a trial at a higher bit-rate so that we can see the impact of lower bit-rates on what we the viewers perceive HD should offer?

  • Comment number 64.

    New blog here

  • Comment number 65.

    @tagmclaren/tagmclaren

    Thanks for that info. If it is indeed correct, then it might mean we can either more or less ignore complaints from the cable side of the discussion, which would also seem to add credibility to the BBC's suggestions that people are just imagining things, or it might indicate a production issue prior to encoding, which would again validate the BBC's claims about the new encoders doing as good a job as the old ones, even if there's a problem somewhere else along the chain.

    That said, there do seem to be tech savvy and knowledgeable people experiencing issues with the sat version, and I would certainly not dismiss their complaints as irrational or imaginary, but I can't help but wonder if the BBC might not have a little bit of a ManuelGate 2.0 on their hands here with a lot of people's outrage, as well as the media reports of thousands of complaints and a possible corporate cover-up, being somewhat of an exaggeration of the actual problem.

  • Comment number 66.

    vletuscandamme #65

    I am indeed one of the people experiencing problems on sat! Definitely not imaginary! I was just pointing out that if my info is correct, I would like Andy to clarify if it is, that the sat encoder has nothing to do with Virgin.

    From my own point of view there are encoder issues and it could be better, but also we have had quite a number of below par productions which have somewhat confused the issue.

  • Comment number 67.

    Well . . . have we not all waited patiently for five days? Carefully and methodically following Andy's blog?

    Fair opportunity has been given for an explanation.

    Whatever happens next and something clearly will, can you really see Sky, The Mail, The Independent all letting this go?

    The BBC will only have itself to blame.

    All of this could have been contained, surely just clicking the variable bit rate switch would have made all of this go away for very little cost? I would imagine over a month or so, the average bit rate would be equitable to the current constant rate.

    And what would that have cost? Nothing like the price I can imagine the BBC will end up paying for this debacle?

    Not only are there people angry about the PQ issue, there are now a whole bunch of people angry at the 'smoke & mirrors', corporate obfuscation and stonewalling.

    Did someone just say 'The Sun' - that would be unfortunate.

    So, there you go, that's two problems you have now BBC HD. Excellent job!

  • Comment number 68.

    Supposedly the BBC have an obligation to use bandwidth efficiently, obviously interms of cost and due to the lack of space on 2D.

    However in the months since the BBC have reduced the bitrate, what has been done with the spare space on the transponder?

    Absolutely nothing!

    I was under the impression the BBC leased the whole transponder, so how would they be saving money or releasing the bandwidth for others to use?

    Andy, do you have a pay as you go tariff on the sat transponder?

  • Comment number 69.

    Dear Andy,

    Thank you for your blog entries this past week. It's interesting to know what is happening at the bleeding edge.

    I think the work into MPEG4 and DVB-T2 has been a technological marvel to be honest, given the timeframes and expertise involved.

    I do realise that bitrate is not everything. Nevertheless; the EVENT of switching encoders corresponded with a perception of a drop in picture quality. There may well be a correlation rather than a cause to conclude that the bitrate was responsible. It may well be something else, I don't know - less I frames in a GOP? - but change there has been.

    There is also the still unanswered questions regarding any oversight and instructions trumpeted from OFCOM about how it has influence on so-called 'efficiencies' to ensure the shoehorning of 4-5 HD channels within a multiplex. e.g. the use of 1440 rather than 1920 pels/line. That small office of your Andy, must be a squeeze with the elephant given use of the swivel chair.

    There has also been, pertinent to this particular blog, some blatant misreading of blogs from Danielle et. al. regarding the use of 25psf/25p. (Notwithstanding when some people refer to a sharp picture, they probably mean correctly focused for maximum detail rather than edge enhanced).

    The luvvies in Drama and Natural History may well wish to indulge in frenzied self-eroticism over the use of this format. But the use of this format, Purely for vanities sake (IMHO) is spreading to other genres where the shortfalls of the format are magnified. There may well be a marginal increase in spacial resolution, however,TEMPORAL RESOLUTION HAS STILL BEEN HALVED.

    For example: Tonight, Live at the Apollo (11/12/09). The camera will pan from the back towards the front of the stage WITH JUDDER. There will be camera pans sideways as the talent moves about the stage WITH JUDDER or waves their arms. THERE WILL be Judder as the APOLLO sign in the back is swept from side to side. There will be no pans up or down for that will exacerbate even more judder. Furthermore, the positioning of the cameras will ensure poor focusing at a distance of the performers. This programme is a case study into why 25P ought not to be used.

    Panorama is also now consigned to 25P (WHY?) which seems to have been outsourced to student operators that seem intent on 'radical' zooms. {irony} good idea with 25p!{/irony}

    25P is not natural motion. It causes problems on any images which are moving - which is a slight difficulty for Television! It is an obsolescent format which is older than 405 lines. It seems that HD makes 25P look even more problematic.

    I realise that I am in a minority position of having extreme views of wanting to watch 'Television' with realism; the least amount of interference or limitations from the medium upon the message. Radical I know, and I suspect, pessimistically, that NechriColor-JudderVision will win in the end.

  • Comment number 70.

    As a Virgin viewer, I'm not overimpressed with the video quality on BBC HD, but I haven't been able to compare it to the MPEG4 on DSat. It certainly doesn't blow me away, or feel as if I'm looking through a window as it did when I first saw Euro1080 on the first true 1920x1080 45" Sharp LCD TV back in 2005. OK, these days I'm only viewing a 32" LCD, but I've followed Andy's instructions and turned all the TV's processing off, yes I have a HDMI lead, set to 1080 signal and have direct pixel mapping, as it is a true 1920x1080 display. I can't say the picture has got any worse, but for a decent spec Sony TV, it's not spectacular, and there is some horrible noise on random shots in programmes such as Gavin and Stacey" even between similar outdoor shots on a fairly bright day.

    Andy and Danielle don't want to comment, but it is clear the Beeb have brought down the satellite bit rates to match that of Freeview HD to ensure Freeview viewers don't get an inferior service due to the available bandwidth. It is the same with SD channels on Freeview vs satellite, they are encoded the same.
    BBC HD is going exactly the same way as DAB in the UK - using technology to squeeze in as many channels as possible, without a care about the quality. It's a shame. DAB should sound much better than a decent FM signal to take advantage of modern speakers, just as HD should take advantage of modern TVs to offer superior sound and vision. Sadly with BBC HD, I'll happily watch BBC ONE or TWO so I don't have to put up with logos onscreen because the picture quality difference is minimal flicking from the SD channels to BBC HD.
    I'm familiar with the setup on HD digital cameras, and think that the issues over the types of filming are just a smokescreen. Other HD channels don't have an issue with the styles of filming, so why should Auntie? To me it appears that they've invested in new encoding technology which is not mature enough for the job, just to get the bandwidth down. If the old encoders are past their sell by date, how is every other decent HD channel managing?

  • Comment number 71.

    "I will try and answer as many as I can but in the end we may have to admit we will never be able to satisfy all of you when it comes to what is or isn't high definition."

    Andy I think this quote is a cop out and a way for you to bow out of the dispute and at the same time save some face. I am very sorry but why do I get the impression that your (The BBC's) agenda is simply to deny that that the HD PQ has not reduced. It is patently obvious that it has. Why would you make the assumption that most people would find a 100% pin sharp picture "distracting" after all this was how the BBC HD picture used to be in the good old days. I want to watch my TV and have it look like I am looking through my living room window THAT IS HD (as real world as possible) and again that is how I remember the BBC HD 12-18 months ago.Switching to a Sky HD broadcast imediatley proves the point and restores my faith in my very expensive 50" Plasma.
    Some BBC HD programs have better PQ than others and I know a bright sunlit beach will always look better in HD than a dark room scene.But again, I am sorry but the sunlit beach on BBC HD has lost that special wow factor and the dark room scene now looks awfull
    I know that I am generalising but I hope I have made a point.There are so many people now making the same complaints that the PQ issue in my opinion must be irrefutable. If your arguments are correct then UP he bitrate for a while and prove us all wrong. I will then leave it alone. If the PQ is still poor then I am no worse off than I am now. I will simply turn BBC HD off.

    Finally and most impotantly if I can read between he lines a little. I think your argument re "program styles" (and therefore varying picture resolution)actually proves that you know the PQ has reduced since the bitrate cut, why else would you attempt to explain the "fuzziness"

    UP THE BITRATE PLEASE!!!!

    Mike

  • Comment number 72.

    sorry about the spelling mistakes in the my previous post. I did mean importantly not impotantly (excuse the accidental pun but that is how I feel dealing with the BBC)

  • Comment number 73.

    @70
    EXACTLY Well put

    Mike

  • Comment number 74.

    Andy, thanks from me too for your efforts. I think enough has been said by everyone else here about today's Blog content. I don't think I can add anything, just my agreement with them.

    wrt the whole series, you tried, I persevered, but in the end I just didn't get the answers I was hoping for. Perhaps we could meet in the pub for a chat one day, I'd certainly like to buy you a drink and hear what you have to say from a personal, and not BBC spokesman, perspective! My hotmail email traffic (and post 64) is telling me that Danielle's posted another Blog, but I'm already hearing that there are no answers over there either.

    Just to repeat, for clarity, the quote attributed to me in the Telegraph today wasn't actually mine. I'd also like to add that I'm sorry we had to engage with the Press, in the end, and regret some of the misquotes and wrong information appearing there, but I really do think we gave the BBC every opportunity to respond to our feedback (which was meant in a + ve way) before we resorted to the Papers.

    Those on my mailing list will already know that Danielle has responded to me, again, today as she was asked to by the BBC Trust. In the event that I am not satisfied with what she has said I will have another 20 working days to submit another appeal to the Trust. After reading your Blog through to the end, as you asked me to, and in view of the lack of answers or even comment from you to the fundamental questions, I'm drawing the conclusion that I will have to do that.

    I notice in recent days that there are very many new BBC IDs making comment. I'll have to wait until my laptop is fixed to say exactly how many (please leave the Blogs up until then Nick) but it's obviously quite a few and like to push the previous 170ish figure well over 200. If any of you are still reading this and want to join in my appeal to the Trust, which I think will be the final resort for us all now, then please help me. Instead of wasting any more effort posting evidence, informed argument and constructive criticism here, please expend it towards composing a single Word document, each, that I can include with my covering letter to the Trust. Each concentrate on what you think you could do best, from impassioned pleas, through technical detail to reasoned argument. Whatever, it will all help and lend weight to the press claims that thousands of people want to have their say heard by the BBC. My email address and further information is here: http://www.zen97962.zen.co.uk/

    I won't say RIP BBC HD, myself, just yet. I have every confidence that common sense will prevail and the "elephant in the room" referred to by others will see the error of its ways. Otherwise, I think, the future of TV in this country will be in the hands of those subscription services who've proven that they can do HD, with the demise of the BBC Licence Fee following in its wake, and neither is something I want to see.

  • Comment number 75.

    Hi all,
    This isn't the first time in my life this has happened. As a young man I was obsessed with hi-fi, and became aware that I was hearing differences between pieces of equipment that couldn't be measured or quantified by the objective tests then being used. This didn't deter me - rather it thrilled me that I had a 'special gift'.

    At an entrance interview for a place at University, I found myself having to justify my - apparently irrational - stance to a Professor. I got my place, and, subsequently, my degree. After graduating I joined, ironically, the BBC. After I got married, my wife, keen to buy domestic necessities rather than exotic electronics, needed convincing. Eventually she became my trusted ally in the search for 'sonic truth'.

    PSNR tests in my opinion are the modern-day equivalents of those hifi tests of THD or IMD - academic tests that don't correlate to the real-life listening (or viewing) experience.

    Does this make me a freak, unrepresentative of the general viewing public? NO! It makes me their champion, without whom mediocrity will rule unchallenged.

    Andy, don't be hidebound by your statistical analyses. Didn't you have 'golden ears' once too?

  • Comment number 76.

    #75: Thanks well said.

  • Comment number 77.

    Pixeljunkie#75

    The PSNR results are flawed. Why did they show (or were presented as) the new encoder being 0.2db better than the previous one and yet we ALL (including Andy) experience gross macroblocking during the camera racking changes on that football match?

    Andy please explain because I am obviously missing the point.

  • Comment number 78.

    @tagmclaren

    i am sure you are right there is something very wrong with the PSNR results. PSNR does not correlate well with the visual experience but it is not as bad as that. It may have somthing to do with the number of different codecs the video went through.

    I watched a recording of Gavin and Stacy tonight and I must admit that is was so bad it was very uncomfortable to watch.

  • Comment number 79.

    Thanks Andy for your interesting and sometimes amusing blogs this week.

    Sadly there are still some very simple questions on here that have never been answered :(

    I suspect this is purely for "political reasons". The only way we will ever get answers is from the BBC Trust (perhaps). Danielle and Andy are keeping quiet. It is of course possible that they have been told to keep quiet by people above them and they only following orders.

    Like Fox Mulder would say The Truth Is Out There....

  • Comment number 80.

    Andy, as you have said the new encoders, are faulty, and you are waiting for a software update to fix them. This means they are "not fit for purpose" why not revert back to the old encoders until they are a fit state for public broadcast. Or even better send them back, and invest in something that works. BBC HD should not be a beta test!

  • Comment number 81.

    Dear Andy,


    First of all, BBC-HD is (was?) Awesome!
    Second, i am from Amsterdam, so please mind two things:
    (1) Officially i should not be able to watch BBC-HD via satellite :)
    (2) Amsterdam, so i am from Holland, so i could be a little direct.

    Anyways, here goes...

    Why all the fuzz and blogs about encoders?
    If you go to http://forum.doom9.org or http://doom10.org you get all the (H.264) encoding lessons you need. The developers of x264 (http://www.videolan.org/developers/x264.html / http://x264.nl%29 are on those boards. x264 is by far the most developed and if you poll it, the best quality H.264 encoder out in the world. This information is relevant for what I'll say later.

    Now just some simple and direct questions?
    Do you WANT superb HD quality or not?
    If your plans are to run a second HD channel on the transponder, just be honest and say so! Everything costs money and this is a great way to save money, but loose some quality.
    If you have the power to provide the world with quality, that stands unique why not consider this:

    Change resolution from 1440x1080 to 1920x1080, this by itself gives a lot more details, the resizing makes the video more blurry then it should be.

    Here comes a sensitive point, information i should not have, but i have it, so I'll use it. I'll leave names out of this.
    You are currently using an encoder which, as we say in Amsterdam, can suck a lollipop! Trust me if i say: your video now with that bitrate on a 52" HDTV is quite bad compared to what it CAN be.
    There is a solution for this, two even:

    Or you use a more decent bitrate, minimal 15mbit, but why not fill it up to the point where the null packet level should be? Unless you need that second HD channel, ofcourse.

    Or you can switch encoder! There are a few encoders out in the broadcast world, that are much better, and one is even close to x264 quality.
    Ofcourse i understand they need to meet cetain settings like working on a STB, but i know those companies are willing to meet your every demand.

    Using another encoder gives you:
    - Much better quality, even on 10mbit
    - 1920x1080, which your old encoder is unable to do, technically
    - A way more updated encoder, features-wise, it's possibilities are endless.


    What disappoints me most is that with these blog posts you are trying to make up for something, that was great, but is slowing losing it's, as anonther user said, WOW factor.
    Not you alone! Sky Cinema HD Germany (Former Premiere HD) also went down the drain. Premiere-HD started with 18mbit CBR, they aired King Kong on it, full frame 16:9 (AR 1.78:1), the quality was so awesome, it was even better than the VC-1 HDDVD Disc! Now they are on 1-12mbit VBR, which effectivly is 5-7mbit, and it looks horrible!

    So please Andy just be honest, why BBC-HD is getting worst and worst!
    - Are you bound by political rules?
    - Is it a money issue?
    - Or do you just don't like us? :)

    Just be honest, in today's world nothing can supprise us anymore, just don't uhm BULLSEYE around!


    Greetings from Amsterdam,

    Jarod Middelman
    x264.nl

  • Comment number 82.


    Dear all - catching up with the comment and in no particular order

    Deaf Simon #80 - the encoders are not faulty they do their job but they can be improved. The old coders were no different but did not handle audio in the same way and were always a potential for errors. The mix/fade issue was known about as I said very early on but the overall improvement in coding was still worth doing. I was at BBC R&D yesterday and we should be able to start testing the fix very soon (have a look at the first blog re what has to be tested)

    Andy

  • Comment number 83.

    Dear PixelJunkie (and others)

    Thank you for the post. I know several people who can spot things just as you can by the way! PSNR is not perfect and if we had used it alone to asses actual picture quality we would have been seriously at fault. PSNR is one of several methods of measurement and if you work within its limitations it is very useful.. Normally we wouldn’t publish these results as interpreting them can often lead to more questions than the results themselves. But in this case (and because some of the posts had asked for the results) we did because we were making a comparison between two devices using the same codec through the same path. I even used the Wikipedia link that says
    "...it is only conclusively valid when it is used to compare results from the same codec (or codec type) and same content…"
    Using expert viewers is the primary method of assessment as always

    Andyused

  • Comment number 84.

    @ Andy Q

    Andy, firstly, many thanks for your series of very informative articles over the past week, they must have taken some time to put together and for that alone you should be applauded.

    Can I ask - why did the introduction of the new encoder happen at the same time as the drop in bit-rate? Would it not have been better to put the new encoder into service and then reduce the rate once it had been seen to be doing it's job?

  • Comment number 85.

    Dear Squegg
    I don't actually have an office - not sure I would know what to do with one! The only elephant I have seen recently is a rather "fetching" ornament my daughter found at a craft fair or something

    I talked a bit about motion in the blog and at the moment we don't plan to make motion a technical requirement - quite difficult to do with the volume of programmes using it. But we do try and make programmes use it properly

    Andy

  • Comment number 86.

    Andy,

    Why does Scandinavia get a higher bitrate than us please?

  • Comment number 87.

    Some posts will take a while to answer so this is a quick scan through - I will come back to some of the once I step over


    Dear hdblogger Thanks for the post #3. Sorry you feel that way but we have had post suggesting HD should always be sharp
    Dear Technogran Thanks for your post #4 - quite interesting it came after hdblogger's comment. We do have programmes that are pin sharp from foreground to background where appropriate (the CIN concert for example) but surely you wouldn't suggests dramas such as Cranford, Wallander and Silent Witness should do the same
    Dear Balderdash Thanks for post #7 and Midzone1 #15 - yes I am very proud of the work we have done from the beginning of the BBC's involvement HD to date
    Dear Mark Jones thank you for post #9 although I do not comment on other HD channels I do watch then and can say we not only stand up well against them, we exceed the quality many times.
    Dear domsmith Thank you for your post #11. You are spot on when you say the technology is still evolving - and it is very quickly. We are looking at various changes to the encoder with the next software upgrade which I hope will start testing very soon
    Dear HD1080 #16 and daveac #17 thanks for the comments. At the moment the choice of 25i or 25p lies with a producer (fiction or non), it is not a technical issue. If a producer wanted to give a programme a colour wash or use graduated filters or make a scene in monochrome, as long as it meets the technical requirements for delivery it is an editorial decision signed off by who ever commissioned the programme.

    Dear tagmclaren thank you for the comment - re updated can I just refer you to the answer I gave domsmith above?
    Dear Mike Bentley and burnlea thank you for your posts - other than day one, the whole blog has been about the PQ in relation to the new encoder. This is common to all programmes and the question I always ask is - has the new encoder affected a programme more to less than the old. In general the answer has been "less" except the comments I made in yesterday's blog about noise.
    Dear jtemplar thank you for your post #26. As a multi genre channel we do have to deal with a lot of different programme types and styles. The current technology does not allow us to do VBR at the moment but that does not mean it will never happen. VBR would allow bursts of higher bit rate if the encoder believed it needed it but it would also allocate lower bit rates if it thought it didn't. The question here is, how do we make sure it uses the most appropriate for the picture?

    I will come back to the rest later

    Andy

  • Comment number 88.

    @Andy

    Please can you tell us where in your test setup the 1440 subsampling is done. I understood that the Playout Server operated at 1920 and that the down sampling was done in the encoder. Where is the downsampling done for the reference stream?

    It is reported here that the BBC has said

    http://crave.cnet.co.uk/televisions/0,39029474,49304459,00.htm


    "We also asked why the BBC was using 1,440x1,080 pixels instead of 1,920x1,080. The answer was, quite simply, that a good percentage of HD acquisition is done at this resolution. It's the format of choice for both HDCAM and DVCPRO HD. It's also much more efficient, especially if you're using interlacing, where each field doesn't have the full horizontal resolution anyway. Anamorphic compression has been in use on digital TV since it was launched -- it's also the way DVDs store widescreen movies."

    Does this mean the video in upsampled first 1920 and then down sampled to 1440. In other words how do you handle 1440 video?

  • Comment number 89.

    This whole episode is very similar to one with the Panasonic BD60 blu-ray player.
    The model has had a problem with random freezes during blu-ray playback which Panasonic had catagorically denied existed for well over six months, stating that it was a disc problem and then only occured very rarely. This was despite blogs, forums and test reviews the world over reporting and commenting on the problem.
    And now, "voila", to much fanfare Panasonic have issued a firmware update that rectifies the 'problem' that never existed in the first place!

  • Comment number 90.

    "The current technology does not allow us to do VBR at the moment but that does not mean it will never happen. VBR would allow bursts of higher bit rate if the encoder believed it needed it but it would also allocate lower bit rates if it thought it didn't."

    Now we're getting somewhere... is that a limitation of the encoder (shouldn't be) or because the HD service on satellite is currently on a DVB-S transponder shared with SD/MPEG-2 services? I believe VBR would alleviate a lot of the problems we are seeing.

    You had a lot to be proud of before the change in August...

    Believe it or not, I think most of the people complaining here are passionate about the service the BBC provides and want to see that "quality" maintained instead of eroded by some poor management decisions. Don't do a DAB on us...

  • Comment number 91.

    Andy,

    Until I read your comment in post 87 ("although I do not comment on other HD channels I do watch then (sic) and can say we not only stand up well against them, we exceed the quality many times") despite my attempts at humour to lighten the tone of these blogs, I genuinely thought you were sincere with the comments that you have been making. I just put it down to the fact that you are so close to what you are doing, that perhaps you sometimes can't see the wood for the trees.
    I now have to be honest and say that that one comment has changed my view completely, and that I now have to question the integrity of all the responses you have provided. I don't doubt, that if the archives are searched, that there have been transmissions where the BBC HD output has excelled, even after the encoder change/bit-rate reduction, but to use those isolated cases as an argument to suggest BBC HD compares favourably with other HD channels beggars belief.

  • Comment number 92.

    For Andy to say as he does above, that BBC HD picture quality stands up to his rivals and even exceeds them is quite patently in many cases now wrong. Sure, it used to, but not any longer.
    I have just watched Episode 7 of The Thick of It, and again the PQ could in no way be described as HD. And 'The Old Guys' Episode 4, no better than SD dvd. And Gavin & Stacey? Come on Andy, you cannot be serious.

    And as for Danielles myth blog response, words fail me.

  • Comment number 93.

    Andy,

    Thanks for the replies.

    What I find very concerning is the mixed messages coming from the BBC.

    Referring to the link regarding freview HDs launch,
    http://crave.cnet.co.uk/televisions/0,39029474,49304459,00.htm

    we are told that freeview HD will be stat muxed with peak bit rates up to 17 Mbits/s.

    So I take it they will not be using the new super duper encoder that BBCHD on satellite is using to deliver superlative quality at 9.7Mbit/s CBR?

    If so, why on earth not?

    Also, the article talks about when the service moves to 5 channels.

    "We were slightly concerned that the expectation is that multiplex B will eventually contain five HD channels. Four, at around 10Mbps each, is one thing, but adding more will surely reduce the quality to unbearable levels. We were assured that, by the time this happens, it's likely that the encoder efficiency will have been increased again, although

    we were told that another reduction of 40 per cent wouldn't be possible"

    So the talk earlier in the week of encoder manufacturers demonstrating good HD at 4-6 Mbit/s are unrealistic?
    "the 8-10Mbs wasn't viable then but is now and in the future 4-6Mbs will become viable"

    Then there are the comments regarding how the encoder will allow for future upgrades. That implies to me that PQ improvements are required.

    Yet we keep getting told it's as good as it needs to be.

    Which is it?

  • Comment number 94.

    Andy,

    How do you go about technically assessing the quality of the output from other broadcasters?

    Can you perform meaningful technical measurements on their entire transmisssion chain or is it a simple case of subjective expert viewing assessment?

  • Comment number 95.

    This cnet quote baffles me:

    "We also asked why the BBC was using 1,440x1,080 pixels instead of 1,920x1,080. The answer was, quite simply, that a good percentage of HD acquisition is done at this resolution. It's the format of choice for both HDCAM and DVCPRO HD. It's also much more efficient, especially if you're using interlacing, where each field doesn't have the full horizontal resolution anyway. Anamorphic compression has been in use on digital TV since it was launched -- it's also the way DVDs store widescreen movies."

    The horizontal resolution of each interlaced field has the same resolution as a full frame. It's the vertical resolution that's different; i.e every other line.

  • Comment number 96.

    The efficiency comment also baffled me. The EBU tests state 1440 requires 12.1 Mbits/s whilst 1920 requires 12.8 Mbits/s. So hardly a huge difference.

    "A good percentage is 1440", but thats changing with more cameras/material being 1920.

    Plus other broadcasters seem to think it is desirable/necessary to use 1920. Surely they want to save bandwidth and costs too?

  • Comment number 97.

    The BBC argument about 1440 is out of date. It has been mandatory that HD is delivered to the BBC in HDCAM SR format since September 2009. HDCAM SR supports 1920x1080 but is aslo backward compatable with 1440.

  • Comment number 98.

    Interesting to have the Virgin question answered. Since, as expected, the BBC's MPEG4 encoder upgrade didn't affect Virgin's service. So what are the 232 Virgin viewers on this aforementioned blog seeing, when they claim the quality has deteriorated recently? http://vmhd.blogspot.com ?

    Is it pure make-believe, after they heard the stories about the 40% drop in bitrate? I might be inclined to say yes. My personal view of BBC HD on Virgin is that there has been no significant change in quality. Yes, you get material that isn't super-sharp, and yes, you get pixelation from time to time, but that has always been the case. This isn't BluRay, it's broadcast quality HD, worts and all, and it seems like the kind of source material that might deliver a great picture still does.

    Now, it would be extremely interesting to see like-for-like comparisons between Virgin and the sat version. It looks like it's fairly easy for sat viewers to grab screenshots, but I'm guessing not so easy with cable boxes? If anyone has this capability, it would be great if someone could post some problematic frames from the sat version, and someone else could find the corresponding frames in a recording from Virgin to see how they measure up. That might tell us something about whether or not any quality problems might be appearing before the material hits the two different encoders.

  • Comment number 99.

    98, CVD, perhaps I can solve the mystery of those 232 Virgin viewers seeing things. I was on of the 232 people who voted, and I haven't had a Virgin box since I got Freesat, and then it was only SD. No, I voted there because I didn't realise it was exclusively for Virgin viewers. I suspect, if it's true that Virgin hasn't suffered from the new encoders or bit-rate change (and why should we disbelieve Andy?), then 231 of the other voters are also Satellite equipped viewers.

    Andy, thanks for your continued engagement with us. I'm thinking that it's just possible that you genuinely believe that the PQ hasn't changed, if so fair enough and I can see that in that case you are standing by your conviction and doing your best to convince us that you are right. However, I really want to believe that you don't, and perhaps that you've got the best of both world's now, i.e. knowing that you can turn around to Management and say to them "well, I did warn you, but I will now do my best to politely placate everyone and tow the party line". I fully appreciate that sometimes, in any field of employment, one may be asked to undertake projects which go against one's own better judgement. Maybe, one day, we'll find out which scenario is the truth.

  • Comment number 100.

    All,

    Danielle has cut and run from her Blog, probably to deal with the more important issues of running a high definition channel than Picture Quality. In her absence, perhaps I can act as a conduit to pass on her thoughts on the "unanswered" questions, as a matter of record. Here they are:

    Q1. Why was the bit rate that the BBC uses reduced?

    The old encoders - which needed to operate at a higher bit rate - were reaching the end of their life and needed to be replaced. Extensive tests showed that the new encoders were able to produce images that we deemed through our technical testing to be similar or better quality to the old encoder at 9.5Mbs rather than 16Mbs. This is because the new encoder exploits more of the AVC toolset than the old encoder and can therefore work with bitrate more efficiently.

    Q2. Could you provide an explanation as to why the previous bandwidth was unsustainable?

    The BBC has a duty to use its broadcast bandwidth as efficiently as possible on behalf of the public, across everything that we do. We therefore aim to avail ourselves of developments in compression technology as they arise where they can help us to deliver an excellent HD service to audiences while making best possible use of the spectrum available. The new encoders have been tested at a range of bitrates to assess their optimal settings.

    Q3. Is there a European bit rate standard and why would the BBC not meet this?

    There is no Europe- wide or international standard dictating the bit rate for transmission in HD or SD. There are technical recommendations set by the EBU which draw from test work done by the BBC and others at a particular point in time. These provide guidelines, rather than standards. The two relevant documents - EBU Tech 3334 (published in February 2009), and EBU Tech 3328 (published in May 2008) - offer "recommendations" on bit rate based on trials carried out by EBU members earlier. None of these trials included the current BBC encoder and were completed some time before the first version was sent to BBD R&D for testing. EBU Tech 3334 also acknowledges that;
    ...with the expected future developments in video coding, it is assumed that HD fixed bit rate requirements will be reduced to 8-10 Mbit/s per programme. There will also be advances in the transmission system such as DVB-T2...

    Q4. Is the BBC adhering to industry standards?

    The BBC is a founder and very active member of the EBU. We take part in every aspect of the EBU’s technical activities. We not only test using EBU standards, we were part of the groups that compile the standards and recommendations in the first place.
    BBC Research and Development is one of a diminishing number of European laboratories with the expertise and facilities to carry out testing for, and make contributions to the EBU’s technical committee. The BBC also plays a leading role in establishing and developing HD production standards in the UK through the approach we take to technology evaluation on the production side, and our role in HD commissioning and production.
    As part of our evaluation of our new encoders, and the overarching issues that have been raised around picture quality, we look at BBC HD alongside a range of other HD channels delivered in the UK and assess comparative as well as absolute technical quality. On the basis of these assessments we are confident that the service delivered by the BBC meets and generally exceeds the standards of other services and providers.

    Q5. How does the BBC assess whether there is any reduction in picture quality or not?

    Our picture quality assessment is based on a combination of Peak Signal to Noise Ratio (PSNR) measurement and expert viewing. The material used to test the encoders is taken from the EBU test sequences and clips from the BBC HD Channel promotion, selected to provide a representative range of content. Further details about the approach we take and the results of testing carried out have now been published as part of Andy Quested's extended blog post on encoder issues.

    Back to me. If you feel that Danielle's answers are inadequate, or don't stand-up to scrutiny, then please let me know via email with a single Word document attached explaining why. I will pass it on to the BBC Trust for you.

    Many thanks. Paul (email address is at http://www.zen97962.zen.co.uk/%29

 

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