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Picture Quality on BBC HD: a Viewers' Group Visit (part 3)

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Andy Quested Andy Quested | 10:05 UK time, Sunday, 6 June 2010

Ed's note: This is the last part of the guest blog by Paul Eaton and the group that came to meet with the BBC regarding picture quality on BBC HD. Part one and part two are already posted on the Internet blog. (PM)

Blog 3: Conclusions and Recommendations

"Following on from our last two blogs we would now like to finish with a final blog of conclusions, and also some recommendations that we make as a group to the BBC.

Personally, viewing my own HD equipment at home, I have experienced, since August 2009, noticeably worse PQ from the BBC HD channel. Public support, in the form of hundreds of emails during my BBC complaint and subsequent Trust Appeal, together with the signatories of the No. 10 Petition and the continuing comments on these BBC Blogs, suggests that I am not alone. Certainly the rest of the viewers' group agree with me.

There is no doubt that the group's visit has given us a better understanding of all the issues. We can now see that there are, in fact, three important variables that can adversely affect the PQ of the channel, namely production decisions and programme quality assurance, encoder software and finally the bit-rate.

However, we still have to weigh what we were told during the day against the evidence of our own eyes at home since August 2009, and there's no escaping that this negative change coincided with the simultaneous reduction in broadcast bit-rate and change of encoder.

The conclusions that we've come to are based on what the group witnessed during the visit, informed by our subjective experiences as viewers of the broadcast HD transmissions.

Our joint conclusions are as follows:
Production decisions and QA - clearly the BBC still has a lot of work to do here. Production and "programme style" definitely can degrade the HD PQ to a very visible degree; that is obvious and apparent on certain programs, as we all know. The BBC does produce some excellent programmes, but their production quality needs to be much more consistent and the average standard must be improved. The failings in PQ that many of us complain about are often attributable directly to programme makers and so, clearly, the BBC has to redouble its efforts to bring them to account.

Encoder software and testing - having seen side-by-side comparisons we can agree with the BBC that, on simple scenes, the new and old encoders (at their respective bit-rates) looked similar. But, as explained in more detail yesterday, when challenged by complex pictures with particular characteristics the deficiencies of the new encoder became apparent. This is where we believe the BBC's emphasis has been misplaced. They seem to have concentrated on a scientific/technical analysis of the picture quality and placed less emphasis on the human, subjective aspect. The test we experienced, although generally conducted in accordance with international standards, is entirely dependent upon the criticality (encoding difficulty) of the material used and whether it "excites" specific problems. It would be all too easy erroneously to conclude from the limited range of materials tested that most material, including material that is 'critical but not unduly so', is similar with the new encoder, and that therefore everything is within the expected performance range. This would explain for instance why the mix/fade issue was identified only after the new encoder was put into service. It also completely underplays how distracting the problems are when they do appear. The artefacts, although transient in nature, are far more pervasive and frequent than the BBC would care to admit. It is on this basis that we feel that Andy's assertion that ''on the majority of material the new encoder is as good as or better than the old" does not represent the overall position adequately. We believe this is another key factor in the perceptions of reduced PQ since August. Ultimately, improvements to, or replacement of, the new encoder may well help to bring about the PQ we all want.

Bit-rate - not being able to see the same encoder run at different bit-rates was a big disappointment to us and we don't understand Andy's reluctance to do a side-by-side comparison of the new encoder with old and new bit-rates. As a consequence, we can only speculate on the effect of bit-rate on the HD channel's PQ and, also, point out the inconsistencies in the BBC's position with regard to its impact. Since we weren't convinced that it has no impact at all it still remains an issue of contention. Whilst we did conclude that the new encoder can deliver the same PQ at a lower bit-rate for undemanding material, the evidence we saw still pointed to the fact that the reduction in the bit-rate has been a major contributory factor in a reduction in the PQ of some material.

We believe that, together, these three issues have all had an adverse affect on PQ but nothing we saw during the visit swayed us from our view that it is the combination of the reduction in bit-rate and the new encoder's problems that has led to the viewers' perception of an overall reduction in PQ since Aug 09. We still believe that an increase in bit-rate would almost certainly provide a considerable degree of improvement in PQ. This belief is supported by the fact that the majority of the group identified the old and new set-ups in the comparison of clips during the R&D visit.

Resolution - Furthermore, we have also yet to be convinced that moving to the higher 1920 resolution will not be beneficial, despite Andy's confident assertions during the day that it wouldn't. If a higher resolution is not beneficial, then why do other broadcasters commit bandwidth and money by using the highest resolution? And since this is the resolution used by the majority of HD channels in the UK, then what have the BBC got against conforming with them? This is even more puzzling when you consider that BBC HD is available in other countries in 1920 resolution.

We note that Andy's assertions also contradict the information provided by the BBC to OFCOM regarding picture resolution on the Freeview HD platform, which recommends a transmission mode that is capable of supporting a 1920 resolution that "maximises the delivery of HD benefits on viewers' increasingly large and high-quality displays".

Recommendations

After an informative, educational, entertaining and enjoyable visit we came away with lots of thoughts. In the last three weeks we've worked hard to pull these together into a list of recommendations that we feel that the BBC should consider adopting. We aren't so naive as to believe that the BBC hasn't already considered them and we are also quite aware that there are commercial and political factors that may constrain them. Nonetheless we believe that by following all of our suggestions the BBC will satisfy most of its discerning HD viewers and reposition itself at the cutting edge of HD delivery in this country.

So, in the group's considered opinion, the BBC should:

  • be even more pro-active in its in-house quality control with programme producers, rejecting programmes where they fail to meet the standards set by BBC HD and improving directives to producers, including those on appropriate cameras, to ensure that only the highest quality HD material is made available to, and broadcast by, the Corporation.
  • investigate ways in which domestic HD productions can be funded so that they can be made using higher quality cameras (be they video or 35mm film) in order to achieve superior PQ, e.g. through partnerships and/or reinvestment of (BBC Worldwide) export profits.
  • continue to work with its encoder manufacturer to improve its current deficiencies and to maximise the viewing pleasure afforded by the BBC HD channel's pictures (i.e. bring back the "wow" factor), whilst also exploring the options for use of other encoders to deliver a more consistent PQ at the available bit-rate.
  • increase the bit-rate on satellite platforms temporarily, since cost is not a significant factor, to compensate for the disadvantage of having to broadcast at a constant bit-rate. The higher bit-rate to be maintained until encoder technology improvements solve PQ issues or a variable bit-rate is introduced on satellite.
  • move from a picture resolution of 1440x1080 to 1920x1080 in order to maximise the delivery of HD benefits on large, high-quality displays.
  • not reduce its purchasing of American-made superior source material programming, in particular drama series such as Mad Men, despite the BBC Director General's recent announcements.
  • speed up the process of introduction of new HD channels so that the next BBC HD channel, the HD simulcast of BBC1, will be introduced before the stated latest date of 2012 with BBC2/3/4 HD following soon after. Otherwise, the Corporation is going to be left far behind in HD broadcasting by its commercial competitors.

Do all these things please, BBC, and nobody will have justification for complaint. Do none of them and, despite the fantastic hospitality you showed us during our visit, we are all still entirely convinced that there will be a case for the BBC to answer, be it to the BBC Trust following the appeal, or to any subsequent "licence fee payers' trust".

To the BBC viewers reading these Blogs, whether you are a seasoned HD PQ campaigner or just a potential HD viewer arriving here for the first time, we recommend that whenever you next view the BBC HD channel you do so with a critical eye. Bear in mind the issues we've raised here and if you think that there is good cause for complaint then make sure you lodge one here. On the other hand, if you are convinced that the PQ is entirely acceptable, or have some constructive criticism, then please do comment about it on these blogs; I'm sure that Andy and Danielle will be pleased to hear and receive both.

And on a final note, the whole group has nothing but praise for both Andy and Danielle for the efforts that they have gone to in engaging with us and also for offering us the opportunity to write this Blog. For that, I thank them once again. They both came across as very dedicated, as did the entire team, and we strongly recommend that those who comment here on their judgements, decisions and actions do so only from a constructive standpoint.

To conclude, we wish good luck to the BBC HD team for a bright, and hopefully complaint-free, future as we hand over to you blog readers and HD channel viewers for your comments about the visit, our Blog and our recommendations.

Postscript

Since the visit there have been two important developments. First, the BBC Trust has approved BBC1 HD. Second, the results of our ITU test have arrived. Since our group size was too small to support meaningful conclusions, our results were supplemented by further tests with other audiences viewing the same material, although our group's results were visible separately and were generally in agreement with the larger audience's results. In brief, our viewers' group (and the wider audience group) thought the new encoder performed better with the EBU material but the old encoder performed better with the BBC material (Lady GaGa). We think the due significance of this result is reflected in the Blog."

Read part one and part two of this guest blog: Picture Quality on BBC HD: a Viewers' Group Visit.

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Comments

Page 1 of 9

  • Comment number 1.

    I would still like to know Andy's views on the equipment/broadcast chain at TVC in relation to the HD PQ.

    Over The Rainbow from Fountain at Wembley had a significantly 'cleaner' picture than similar shows from TC1.

    Graham Norton, from The London Studios, much better PQ than its TC4 counterpart, Jonathan Ross.

  • Comment number 2.

    Ok the $64,000 question to Andy ... ever since the debate about picture quality was raised on these forums the one factor at the heart of the problem we believe is the reduction in bit rate. This being the case can you tell us why the team were not being able to see the same encoder run at different bit-rates? This would surely have shut us all up for good - however what is has done has made us all think you have something to hide?!?!

    Please don't skirt around this lets have a straight answer once and for all.

  • Comment number 3.

    I've got to agree with Midzone1 - this looks like a great deal of effort was put into this visit by all concerned, but the one critical experiment that would have answered the question of whether a bitrate increase would help or not, was avoided. That doesn't look good.

  • Comment number 4.

    "In brief, our viewers' group (and the wider audience group) thought the new encoder performed better with the EBU material but the old encoder performed better with the BBC material (Lady GaGa)."

    That's quite an important point - is the consistent use of the EBU reference material in encoder testing a bad idea? Is it now an unrealistic test, not at all like the real-world source material that has to be handled on a daily basis?

  • Comment number 5.

    Dear Midzone1 - thanks for the post. I think the answers are in the results of the ITU tests.

    Dear James R Ginter - thanks for the post. I am sure the group will post re the BBC and EBU material. The EBU test material was made to test encoders to allow results of different types and settings to be accurately and repeatably measured. The BBC material was deliberately chosen (by me) as a piece that demonstrated our encoders poor handling of mix/fade - in this case changing light levels - it should have been worse than the old. The interesting fact is the actual scores of new vs original and old vs original.

    Dear Derek500 - I will look into the differences you pointed out. The studios on Television Center are owned and operated by Studios and Post Production Ltd. The lines from our central switching area to the Red Bee playout area are the same no matter where the (live) programme comes from - so would have been the same for Wembley/London Studios/Television Centre Studios.

    Only two things spring to mind - light levels in the studio and gain in the cameras. It may take a bit of time but I will check

    Andy

  • Comment number 6.

    #4 James R Grinter

    Clearly using the EBU clips for comparison purposes has enabled Andy and his team to truthfully claim that the new encoder/bitrate combination is as good as or better than the old encoder/higher bitrate for most material.

    There are 2 points to be made here.

    1) The one clip we, and the wider test group viewed (Lady Gaga on the Jonathan Ross show) that was better on the older encoder/higher bitrate was the only clip of the set recorded with artificial lighting conditions. The other 3 clips were all outdoors in less demanding, very good natural lighting conditions. This is significant and bears out what we have been saying for a long time now and that is that for most undemanding material the picture quality has not deteriorated since August 2009. However, in the real world, a lot of the programs transmitted by the BBC contain demanding material, and that is why we started seeing problems from August 2009 that we didn't see before.

    2) Testing the new encoder/lower bitrate against the pre August 2009 encoder/higher bitrate as a basis for determining acceptability of HD picture quality is flawed. This pre-supposes that picture quality was OK on the old encoder/higher bitrate. Clearly a look through the BBC blog archives shows that this was not the case. A better comparison would be to compare the new encoder at 9.7 Mbps against the configuration (19 Mbps) used in the early days of the BBC HD trial, when the picture was unquestionably HD.

  • Comment number 7.

    Dear burnlea - Thanks for the post - the EBU clips are designed to test and push encoders as you pointed out in part 2 - good light or not. You even comment on the EBU's description of difficulty - two of the clips described as "difficult". Through many of the posts we have been accused on not following EBU guidelines - I think there can be no doubt now that you know we do and we take the testing process very seriously.

    I really must disagree with you second comment - surely the only valid test is to show the original against the coded - after all the aim of all the work we are doing is to make the encoded picture indistinguishable from the original is it not? If we achieve this, any comment on the quality is about the programme itself.

    Andy

  • Comment number 8.

    As I commented in part 2:
    Gents, thanks to all that have spent a great deal of their time in (a) visiting the BBC and (b) doing the write up afterwards.

    However, I am sad to say that because of this HUGE omission "Failure to Demonstrate the New Encoder at the Old Bit-rate", I conclude that all your efforts were entirely wasted. This surly must have been the cornerstone of the whole debate.
    AQ – this smacks of a deliberate mis-direction on the part of the BBC team – shame.

    Yes SHAME on the BBC. This single issue needs a PUBLIC ENQUIRY!

  • Comment number 9.

    > "To the BBC viewers reading these Blogs, whether you are a seasoned HD PQ campaigner or just a potential HD viewer arriving here for the first time, we recommend that whenever you next view the BBC HD channel you do so with a critical eye."

    I'd cautiously ask if this is necessarily the right way to go about it. Specifically looking for flaws is the best way to find them.
    Surely the best way is to just watch a program and see if anything takes you out of the program?

    If a flaw jumps out at you, then yes it obviously needs addressing. But as soon as you sart looking for discrepancies, you find that you can't help but notice every bad edit, dodgy composit or evidence of a previous take.
    (Like tyre tracks on a carpet before someone rides a bike inside a hotel.... see True Lies)

    If bad encoding is really noticably awful (and I've seen some like that both on live TV and on internet video), it can pull you right out of the story or program and you will notice it without even trying. If it doesn't show up without trying to see it, is it really a problem?

    Heck, I've seen bad encoding (or bad production values) that take me out of the moment less than a continuity announcer over the credits or an on-screen "now/next" trail.

  • Comment number 10.

    #7 Andy Quested

    "surely the only valid test is to show the original against the coded - after all the aim of all the work we are doing is to make the encoded picture indistinguishable from the original is it not?"

    Agreed, but none of the tests we participated in concluded that the coded output was indistinguishable from the original. The fact that during the original/old encoder/new encoder viewings, the original was immediately identifiable means that the BBC is still some way from making the coded picture indistinguishable from the original. Perhaps comparing the HD trial coded output against the original would have demonstrated better convergence. :-)

  • Comment number 11.

    Andy, re. your second paragraph in #7, isn't there a logical slippage here? burnlea is clearly not making a methodological point, saying that that we should be directly comparing encoder output A against encoder output B. Rather, while the introduction of the new encoder did indeed trigger this latest round of complaints, the previous one at 16Mbps in turn should not be the benchmark for PQ, a point we made in part 2 of the blog. The new encoder could score better than the old yet still not be as good as the setup prior to both.

    Here I'm just trying to clarify the logic of your response.

    At some stage I hope people will consider the points we've made about the range of the two ('old' and 'new') encoders' performance, and the discussion of the nature of the objectionable artefacts we identified as characteristic of the new encoder (mix/fade aside). Factors such as these move us on from simple blanket 'better/worse' judgments to perhaps more meaningful analysis of how we arrive at such judgments, and thus more precise descriptions of what picture quality means. That was one of the aims at least.

    (Just checking before posting, I see burnlea's already responded but this still seems worth adding.)

  • Comment number 12.

    I am slightly confused now, will the two BBC HD Channels have VBR on Freesat? Or is that being worked on?

    Kyle

  • Comment number 13.

    To the visitors group-
    Turning the argument on it's head for a while..
    Instead of examining the defects or how similar were the different versions of what you were shown, did any of you see any
    HD that was pure unmistakable 'WOW' as it was in the early days..
    If not something's amiss. if you did see it -what was the setup.

    To Andy The VBR or stat Mux for BBC1HD and BBCHD will have what baseline bitrate? eg-will you run at 6 for undemanding/slow mo shots and jump to 9.7 for action/ crowds etc or will you have a low baseline of 9.7 and say jump to 12 for the difficult/demanding shots.

    Thanks go to both sides for the civilised manner in which they have conducted the discussions despite the continued fundamental disagreement over what constitutes acceptable HD as delivered to consumers as opposed to what ticks boxes in the lab.

  • Comment number 14.

    #13 John 1961

    "did any of you see any HD that was pure unmistakable 'WOW' as it was in the early days"

    I recall commenting to one of the other vistors on the day that nothing stood out as good HD, so the answer is categorically no!

  • Comment number 15.

    It would appear now the blogs have all been posted - & a big thank you to our visiting team, & to the BBC for providing the opportunity - that we are no further forward, quelle surprise! The BBC remains entrenched in its position & intransigent on all major issues raised on these blogs, & we now have confirmation that platform neutrality is the arbiter of PQ. What a sorry state of affairs, BBC hang your heads in shame.

    Andy, can you confirm that upon the launch of BBC1 HD & the promised stat-mux with the existing BBC HD, the transponder for DSat Astra 2D @ 28.2 degrees East will migrate to DVB-S2 & the two SD channels BBC1 East & BBC1 CI shunted to another transponder?

  • Comment number 16.

    Thank you burnlea
    Clearly something is very much amiss here.
    With the object of this campaign being to restore PQ back to the level it once was or to exceed it, then comparing one set of good HD with another set of good HD and seeing differences in how they handle challenging conditions somehow misses the mark.
    I have not seen any Stunning HD for a while , however well the old and new systems compare..
    Perhaps the stat mux will help, but at any rate Knockout HD is like sneezing- you know it when it happens. If you're not sure if you've sneezed- then you haven't.

  • Comment number 17.

    #17 John1961

    I love the sneezing analogy. Maybe we should organise a co-ordinated 'sneeze in' and see whether that will get us a PQ improvement ;-)

    As you correctly concluded, this campaign is not about returning the PQ to how it was at the beginning of August 2009 before the encoder change/bitrate reduction, as that was not acceptable either.

    There is hope on the horizon however, as Andy has now introduced the first stage of the software update to address the mix/fade issue, is talking of further software updates ("some of the other work to improve picture quality over and above the old encoder is nearly ready to be uploaded") and the biggest benefit could be from statistical multiplexing provided that isn't crippled from the start by setting the top limit to the current 9.7 Mbps.

  • Comment number 18.

    First of all thankyou to all the people who put such alot of effort into this visit.

    Unfortunately I agree with nur0

    "The BBC remains entrenched in its position & intransigent on all major issues raised on these blogs"

    This is confirmed by lack of response by the BBC Trust to Paul's appeal.

    It does seem that our only hope is in the Government's intention to change way the BBC is run.

    The one thing that has amazed me is the amount of technically incorrect information the BBC has put out in their defence. The latest example being the 1920 vs 1440 argument. The BBC use to be the bastion of technical excellence and it it very sad to the the BBC stoop to such tatics. Unfortunatly this has been happening in other areas of the BBC such as DAB radio.

    There are 41 HD channels available in the UK and so the BBC is a very small player in the HD market. So is it worth trying to get the BBC to change its position. As far as I can see there are 2 reasons for continuing.

    1) We all are forced to pay the TV licence so why should we put up with the worst picture quality.

    2) The BBC has protected rights on some events and so we don't have any choice and have to watch certain events on BBC. This includes the World Cup. If Sky also had rights to the world cup we would not only have a much better HD picture some matches would be available in 3D.

    The BBC use to be a leader in technology but now it is actually hindering the case for HD by producing such a poor quality output. Anyone looking at BBC HD now is likely to conclude that there is not much difference from SD.

  • Comment number 19.

    Dear Nick Mason & John1961 thanks for the posts. As I said earlier and burnlea acknowledged, we should be trying to make the images as close as close as possible to the original (if not striving to make then indistinguishable). That's why standard testing is always against the original - testing one process against another proves nothing unless you can see every possible scenario.

    Dear HD_fan428 and burlea - thanks for the post. We always aim to improve quality and we are now better than pre August quality and still getting better :)

    Dear Kyle Rickards - thanks for the post. At the moment Freeview is a statistical multiplex therefor VBR but with other channels influencing the bit rate available. Sat is CBR at the moment, I hope we can move to VBR soon but with the launch of BBC One HD, sat will be a stat mux too.

    Dear nur0 - thanks for the post. I assume yes but, I am not sure what the timescales for S2 and moving the two regions to another transponder.

  • Comment number 20.

    Andy, you have still failed to adequatly answer why BBC HD is broadcast 1920x1080 and we are lumbered with 1440x1080. As your test showed, if it made no difference, then why are all the other HD broadcasters and equipment manufacturers wasting their time with full HD.

  • Comment number 21.

    I meant 1920x1080 BBC HD to the rest of europe

  • Comment number 22.

    @13 John1961 wrote:

    did any of you see any HD that was pure unmistakable 'WOW' as it was in the early days.. If not something's amiss. if you did see it -what was the setup.

    Yes. The source material :-) e.g. the source material from the Children in Need concert at the Royal Albert Hall as mentioned in part 2, was Jaw droppingly good.

    The fact that it wasn't so good when we viewed it through the encoders makes highlights the issues surrounding the claims that broadcasting at 1920 resolution nor higher bitrates make any difference to the PQ, as that is exactly why such source material does look so good compared to what we see broadcast.

    Of course, we aren't going to see 35mbs+ bitrates any day soon... but even so, it still makes the point that bitrates do matter. (however, marginal an improvement from 9.7mbs to 12mbs may be, it's still an improvement)

  • Comment number 23.

    #19 @ Andy Q, thank you for the reply re. S2, that at least is very encouraging news. We will then have the existing transponder dedicated to HD, & with only the 2 BBC HD channels stat-muxed on there the PQ should improve! Removal of the 2 SD channels is great news.

    LinowSat shows that tx as having 33.79Mbps capacity. Can you please confirm that the entire tx will be used for the 2 HD channels, & we will not be subject to a re-run of the current situation whereby there is massive wastage due to nullbytes? Can you please advise as to what is meant by Audio/Data @ 21.33% of the tx capacity on that LinowSat piechart:


    http://www.linowsat.de/cgi-bin/suggest/forward.cgi?txtSearch=BBC+HD+28.2%C2%B0East+%2810847+V%29&cmdSearch=Go

    One assumes the move to S2 will be in place BEFORE the launch of BBC1 HD?

  • Comment number 24.

    Dear citizenloz - thanks for the post -actually the CIN concert you saw was around 130Mbs i-frame and because the master was HDCam, it was 1440x1080 native, HDCam is one of the formats we hope to phase out soon though as it does cause us multi-generation problems.

    Dear zubeirp - if I really wanted to be facetious, I could say most of Europe is 1280x720 :). We did show that even fed directly from an uncompressed 1920 master the 30MHz grating did not resolve. The 25MHz grating was visible and around full level. At 1440 the 25MHz grating was visible but at a reduced level.

    Andy

  • Comment number 25.

    I decided to wait until after the last blog post was published before commenting... so here we are! Feels like so long ago since we were at the BBC.

    I would like to express my personal gratitude to Andy and the team at the BBC for their hospitality during the visit. Regardless of the state of the debate, I have a new-found appreciation of the BBC 'back room' boys and their obvious dedication. I mentioned on a social networking site not longer after the visit: "I thought I was a geek until I met the BBC R&D team"!

    I would also like to reiterate a point made in this blog regarding keeping the debate constructive. While the vast majority of posters on these blogs (particularly the 'Salmon of Style' post) have managed to keep the discussion respectful, cordial and factual, there have been some exceptions. Calling for people's sacking is completely unacceptable in my opinion and such statements totally devalue this debate and reduce any incentive that Andy, Danielle, etc. have to continue to engage via this medium. They're under no obligation to do so... as they were under no obligation to invite a group of us for the day. I hope we can continue to maintain mutual levels of respect.

    Cheers,
    DE

  • Comment number 26.

    Dear digital_elysium - thanks very much for the post. I hope you've had a chance to look at the new settings over the weekend. We also hope to have the next update ready very soon (in time for the WC) and I will keep you all up to date

    Andy

  • Comment number 27.

    @24 Andy Quested wrote:

    if I really wanted to be facetious, I could say most of Europe is 1280x720

    There you go, obfuscating again... and never answering the question.

    Who cares what the rest of Europe do? We are discussing a UK broadcaster in comparison to other UK broadcasters are we not?

    Beside which, please provide evidence to back up your claim that "most" of Europe is 1280x720. I would be most interested to see that list!

  • Comment number 28.

    Andy Q, please can you respond to the points I raised in #23?

    I would add that it is very encouraging to see you replying to many of the points raised & in a speedy timeframe.

  • Comment number 29.

    I have been quite 'active' on these blogs since the publication of our visit report and its recommendations. I would like to share my reasons why.

    Prior to the visit, I was of the view that transmission parameters (bitrate, compression etc.) were the cause of the majority of the picture 'distractions' I starting seeing since August 2009. However, I went to the BBC with an open mind, as I believe all the visiting group did. That open mindedness enabled me to see, when presented with information and reasoned arguments, that other factors, such as poor source quality, inferior cameras, poor lighting decisions etc. also contribute to the perceived picture quality. That was quite a shift of my (and I suspect other members of the group) position.

    However, despite similar reasoned arguments and the provision of information to the BBC HD team, we have seen no such shift in position on their part.

    To say I am disappointed is an understatement. Andy's continued defence of the indefensible is frustrating in the extreme. What do I mean by that? The ITU tests clearly showed that the current encoder/bitrate doesn't handle demanding material such as the Lady Gaga performance on the Jonathan Ross show as well as the old encoder and higher bitrate. Andy will argue that this was because it contained mix/fade segments which he has acknowledged was a problem for the new encoder., However, there wasn't 'mixing and fading' occuring all the time in that clip, but the quality was worse all the time on the new encoder/bitrate setup. This is proof positive to me that with certain types of demanding material, the new encoder/lower bitrate does not perform as well as the old setup did.

    Perhaps an acknowledgement from Andy that this scenario is one that falls outside of his oft repeated statement that 'the performance of the new encoder/lower bitrate matches or exceeds that of the previous setup for the majority of material' would make me feel less frustrated.

  • Comment number 30.

    Hello all,
    Firstly may I add myself to the list of people thanking both the BBC and Paul's team for their time and efforts?

    Personally I still remain unconvinced by many of the BBC arguments that have been put forward, but I must say that overall PQ does seem to be improving (slowly) - however there is still no "wow" factor. Hopefully the upgrades planned for the WC will get us a little closer to our objective.

    Now onto a more technical point. The changes made last Friday (noise reduction I believe) seem to have made a difference to the (sat) transport stream.

    I have just run Saturday's Dr Who Confidential through my indexer, which kindly gives a running commentary on bit-rate etc. and noticed some changes. I already posted this on Salmon of Style asking if BBC HD had not already gone VBR (Andy asked me to repeat here) due to the changes that I noticed.

    As far as bitrate goes, it now seems to vary between about 8.6 and 10.5 with an overall average of 9.3 and a max of 14. Previously it varied much less (8.9-9.8) and generally gave a max of 11. It might just be me (I just got new glasses) but it appears that there has been a change there.

    At the same time field structure is now a mix of TFF and MBAFF. Previously it was all MBAFF until the encoder change when it switched to all TFF. Is this something to do with the improvements?

    Finally my take on the 1440/1920 debate. I don't care whether a 25 or 30 MHz signal is resolved or not, at some point the 1440 pixels have to be stretched to 1920 - either in the STB or in the TV - and either of them are likely to make a pig's ear of it at some point. Surely encoding 1920 pixels rather than 1440 gets up to 33% more information through to the decoder?

  • Comment number 31.

    Andy,

    You say you want to move to VBR on sat. What is you expected range of bit rates?

    A slight aside to this question, is freeview HD using the same encoder as sat?

  • Comment number 32.

    #30 CliveLu

    I've just checked Linowsat and there is no apparent change in bitrate for BBC HD over the last 3 days.

    I'm not convinced the latest software changes have been generally beneficial. They may have helped the mix/fade issue, but have they had some other undesirable side effects? Saturday's Doctor Who exhibited much more loss of sharpness during movement than the first episode did (I have it recorded and replayed it as a reference).

    Having just watched Soccer Aid 2010 on ITV1 HD, this was exceptional HD picture quality tonight. If they can do it, why can't the BBC?

  • Comment number 33.

    Andy please could you respond to post 23.

  • Comment number 34.

    Andy

    You keep refering to the nyquist frequency. As I pointed out in a previous post this applies to the sampling of an analogue signal. Please can you get one of your engineers to explain how this is relavent in a digital system with no analogue component.

    You also talk about a grating frequency which again is a term used in the old analogue television system. Please can you explain exactly what your engineers mean by a 30 mhz grating in a digital television system.

  • Comment number 35.

    A big thanks to everyone concerned.

    From what I've read so far, basically, we are back at square one. It's down to poor source material. A higher bit-rate would improve it but that's never going to happen.

    Is the trust appeal still going ahead after this group visit to the BBC?




  • Comment number 36.

    Andy

    Please don't reply to my post #34 as I have found out the cause of the confusion. I will post later.

    Trevor

  • Comment number 37.

    @32 Had a look at Soccer Aid last night, it was also on STV HD (currently testing) and they're using 1920x1080 resolution. No instantly noticeable difference to ITV1 HD's 1440x1080.

  • Comment number 38.

    I cannot comment on the technical issues discussed, but as a "mere" viewer I hope my observations are useful.

    BBC HD picture quality is very good indeed, but compared to some of its rivals it's extremely lacking.

    Two examples: during the recent winter Olympics the moguls were being shown on BBC HD and Eurosport HD so I was able to make a direct comparison. During slow moving or static shots there was no discernable difference, but on high-speed tracking shots over the moguls Eurosport HD won hands down. You could detect every little imperfection on the surface of the snow, whereas on BBC HD the course simply became a white blur. It's a shame Eurosport had to spoil things with a massive and intrusive DOG, but even that couldn't put me off.

    Second example, my better half enjoys watching WWE on Sky One HD. I'm not a fan myself, but couldn't help noticing how well Sky coped with some extremely challenging source material - dark scenes, sudden transition to floodlighting, pyrotechnics, smoke machines, fast-moving camera panning. While the "sport" itself may have been lacking, the picture quality was simply staggering.

    It does strike me that whatever technical arguments may exist, the end result for the average viewer is that BBC HD just doesn't come up to the standards of other broadcasters.

    I happily pay my licence fee because I strongly believe that the BBC should be the best broadcaster in the country (if not the world): not just with the quality and range of its programming, but also with championing technical standards and the best possible user experience. For a corporation with so much to be proud of, the HD channel is a giant zit on an otherwise beautiful face. It needs popping. Fast.

  • Comment number 39.

    @35 I've always maintained the source material is the problem.

    Last night caught up with two BBC HD dramas. 'Worried About the Boy' and 'The Secret Diaries of Miss Anne Lister'. They were both excellent picture quality (shame about the locked 5.1!!).

    Last week I saw a bit of 'Rick Stein's Food of the Italian Opera', unlike previous Rick Stein programmes, the PQ was very disappointing. Lot's of outside, naturally lit shots, but the end result was so soft.

  • Comment number 40.

    Derek500 #35,

    No one is denying that the source material can be and is often a problem.

    However it is not the only problem. The new encoder introduced specific problems which on certain material are plainly visible. Problems which are not seen on the old. These problems are more pervasive than the BBC acknowledge and are only starting to be addressed after 9 months of lots of shouting, with the first of several software updates last Friday. This is disapointing.

    The point is that BBCHD PQ has not been as good as it should or could be. Hopefully the package of software updates will improve matters, which is what I am personally now more interested in focussing on.

    Hopefully Andy can share more details about what these updates addressing and over what timescales they will be introduced.

    Andy says there should be another this week (the fact they are trying to get it in so close to the World Cup is intersting ;-) ) but I presume the system will be locked down for the duration of the tournament.

  • Comment number 41.

    That's quite an important point - EBU reference material in encoder testing

  • Comment number 42.

    @Derek, I think the point is that when the source material is challenging the encoder doesn't cope at the current bit rate.

    There's no deying that some programmes are poorly shot, but that alone doesn't explain the problems that clearly become visible when encoding becomes challenging.

  • Comment number 43.

    Copied over from Part 1 where I think this has no got lost:

    In reference to Andy's comment that the BBC are pursing a policy of platform neutrality (please go to part 1 here http://www.bbc.co.uk/blogs/bbcinternet/2010/06/picture_quality_on_bbc_hd_a_vi.html to pursue the whole thread if this isn't self explanatory)

    "What I'm suggesting Andy is that the bit rate shouldn't be reduced just to accodate Freeview's bandwidth failings but rather if you are pursuing platform neutrality, what should be being done is a bit rate set which maintains high quality HD and then apply this to all available platforms. If that bit rate falls above Freeview's available space then Freeview should be transmitted at the reduced bit rate alone (but at the maximum level available for that platform). That is platform neutrality, not reducing every platform just so as to avoid others looking better than Freeview.

    Astra commented a while ago that below 12mbs they get complaints about HD quality. Therefore this begs the question as to why the BBC haven't set 12 mbs or above as the BBC HD standard? There can only be one answer here from your answer above, because Freeview can't accomodate 12mbs.

    However, the point I've been trying to make is reducing all service below the optimium level just to make Freeview look good isn't platform neutrality but rather bias towards Freeview.

    What the BBC should be doing is applying the optimum bit rate, be that 12mbs or more, then applying it to all platforms and in the case of Freeview where it can't be accomdated, instead applying the highest possible level that can. That is neutrality."

  • Comment number 44.







    Andy
    Again the fact is the PQ on the Jonatham Ross show is still very poor,
    do you think i should be seeing ie,

    bad artefacts and noise that move around all over the place,
    still i am seeing a very soft looking picture,
    i can still see motion blur,
    medium to wide angle camera shots look washed out and lack detail.

    The bottom line is i am watching sub standand HD on BBC HD still
    affer nine months. if i then change channels and look at Sky news HD
    i can see the wow factor again, HD that looks like HD.....

  • Comment number 45.

    It seems that, despite all the hard work from everybody here, we are still in the same position as we were last year. The BBC refuse to acknowledge that there is a problem despite all the complaints and evidence to the contrary.

    I was hoping for a more positive response from the BBC but that now seems unlikely. I realise Paul_G is away for a few weeks but do we have any news on the position of the BBC Trust, which now seems the only course likely to get some results. It seems fairly clear that they are not fully complying to their remit:


    "BBC HD should deliver a very high quality technical service to viewers, by adhering to, or seeking to exceed, industry standards for picture resolution"


  • Comment number 46.

    @44 Jonathan Ross has been poor since it was first broadcast in September 2008. I among others were complaining about the PQ back then.

    I still believe there is a problem with TC4 where it's filmed. Andy (see above) has promised to check it out.

  • Comment number 47.

    #45 orange_and_lemons

    In Paul's absence, the last communication I am aware of from the Trust was 21st May, advising that a committee had not yet met to consider his appeal. The trust have been copied with our complete visit report as published.

  • Comment number 48.

    @45 orange_and_lemons asks "do we have any news on the position of the BBC Trust"?

    Reading through the blogs it seems we didn't make it clear that representatives of the trust were present for part of the day. In particular, they participated in the subjective testing detailed in part 2 and then left shortly after. Perhaps that was their main reason for attending. They would also have been provided like us with the full analysis of those tests.

    Though we have put across several arguements in the blogs as to why the tests were not necessarily conclusive, the fact remains that in the case of the 3 'standard' EBU clips the new set up was judged on average to be marginally better overall than the old encoder/bitrate setup.

    Therefore one assumes the BBC Trust will take those tests into account when making their decision. Hopefully though, they will also take into account the group's comments on the tests as well as the recommendations in this blog.

  • Comment number 49.

    Derek500 blog 46
    I need to make this point to you, i have been watching the bbc HD
    channel for a long time now on Sky HD, i have been watching BBC HD
    for 10 months before the encoder change and the bit Rate Cut, the
    fact is i saw the Picture Quatily Drop, and the Jonathan Ross show
    did not look this bad.
    Believe me i do no what i am talking about, its so easy to spot
    very poor Quality HD on a 52 inch full HD screen.

    And the fact is the lower the Bit Rate gos, the lower the picture
    Quatily is, ie more PICTURE COMPRESSION less DETAIL......

  • Comment number 50.

    Thanks for the blog post.

    I have to conclude that BBC HD can not provide the highest quality HD Picture Quality and 5.1 sound is too expensive to provide normally.

    I had hoped they would change their bit-rate decision. I do not understand why they can not.

  • Comment number 51.

    I read this series of blogs with interest

    I did think from earlier blogs and comments that some questions were not being answered, this invitation to the viewers group has enabled many points to be clarified.

    As mentioned above :
    "We aren't so naive as to believe that the BBC hasn't already considered them and we are also quite aware that there are commercial and political factors that may constrain them"

    Such factors probably explain:

    - "we have also yet to be convinced that moving to the higher 1920 resolution will not be beneficial, despite Andy's confident assertions "

    - "and we don't understand Andy's reluctance to do a side-by-side comparison of the new encoder with old and new bit-rates."

    But it does seem to have been a useful exercise, for which the BBC was thanked
    "And on a final note, the whole group has nothing but praise for both Andy and Danielle for the efforts that they have gone to in engaging with us and also for offering us the opportunity to write this Blog. For that, I thank them once again."

  • Comment number 52.

    And a big thanks too of course to the Viewers group for all their efforts, otherwise the invite would not have been extended by the BBC for the visit or the blog

  • Comment number 53.

    @ 49 'did not look this bad'.


    So you're agreeing that Jonathan Ross looked bad before the bitrate cut/encoder change?



  • Comment number 54.

    It's interesting that you all thought the Angel Falls clip looked as good as the old encoder.

    The bottom line is this new encoder struggles with demanding stuff. You don't need to be a rocket scientist to work that one out.

  • Comment number 55.

    Derek500
    Has i said Jonathan Ross looked alot better to me before the Bit Rate
    cut, I am sure as alot of other progarms looked sharper and cleaner
    looking as well, and not soft looking....

  • Comment number 56.

    128fish - Derek's point is that there were widespread (and acknowledged) complaints about the PQ of Jonathan Ross long before discussions of bit-rates and encoders ever began. This was widely believed to be a problem with the transmission chain from the studio where it is filmed.

    Therefore, referring to Jonathan Ross as an example of the 'drop in PQ' is likely to get you ignored. Derek is trying to do you a favour.

    Similarly, by repetitively harping on about a blanket drop in PQ (and failing to acknowledge when the PQ is OK or good) is also out of step with the majority of posters, and certainly most of us who attended the visit to the BBC. We don't believe, and have never stated, that the drop in PQ is uniformly visible. In fact, as the ITU tests showed, there are some cases where the new encoders actually perform better than the old ones. One particular scene of Survivors jumped out at me. The old encoder completely collapsed when a car pulled into shot, while the new encoder coped much better.

    Indeed, we as a group have made a statement that we believe in many cases, when the encoders are not being challenged, the PQ is at least as good as it was before. The focus of our complaints are the times when the encoder is challenged; the new one, in certain events, copes far less gracefully than the old one did - and we believe bit-rate to be a major variable in this.

    As a regular poster here you have the opportunity to contribute positively. But at the moment, your Haiku-style aimless complaints aren't really helping anyone. If you focused on the programmes and scenes where you notice a specific problem, it would be far more useful to all. Are far less tiresome to read.

  • Comment number 57.

    @ derek500. I think just about everyone on here aggrees that the BBC need to improve its production methods, but I think most people also can see that the bit rate is simply far too low. Anything challenging and the encoder cannott cope.

    Would you say Doctor who is produced well??? It looks like it has great production to me yet the picture clearly struggles when something challenging happens in this.

    In regards to Jonathan Ross, another show that has always looked bad and I dont think anyone disagrees with this. The point is the encoder cannott handle the bright lights and poor lighting.

    As for Andy Quested, without actually saying it, I think he's made it clear that Sky viewers are having to suffer such poor picture thanks to freeview HD.

    For me BBC HD needs cleaning out from top to bottom and some fresh ideas from new people.

  • Comment number 58.

    For the benefit of those who read this Blog yesterday or early today I thought I'd better draw people's attention to a single word error in the original version. The mistake was mine, and the BBC have very kindly amended the published version. In the 'Encoder software and testing' section it originally said:

    "It would be all too easy to conclude from the limited range of materials tested that most material, including material that is 'critical but not unduly so', is similar with the new encoder, and that therefore everything is within the expected performance range."

    It now correctly says

    "It would be all too easy *erroneously* to conclude from the limited range of materials tested that most material, including material that is 'critical but not unduly so', is similar with the new encoder, and that therefore everything is within the expected performance range."

    I hope that our position is now clearer, and that the sentences following this one make more sense!

  • Comment number 59.

    Dear all - two things.

    1. I have just sent a quick 1920 explanation to the EBU display group to check for errors before I post it and

    2. Did anyone watch Spring Watch? The butterflies sequence was "exceedingly" challenging and the new up grades not only coped but showed some camera errors!

    Andy

  • Comment number 60.

    #59, yes just watched Spring Watch on Freesat HD - it looked very good, but then it did last week too. I guess we'll have to wait until tomorrow to find the upper limit for DSat VBR from LinowSat.

    Andy Q, please can you respond to #23?

  • Comment number 61.

    Andy Blog 59

    Spring Watch.
    You are right about the close ups of the butterfies sequence, ok that
    bit was good, But when i was watching the medium to wide angle shots
    of the poeple talking, no its not the best Quality HD, again just
    look at there faces lacking in detail and looking washed out.
    I still think to fix the Picture Quality Problem we need the higher
    resolution on BBC HD and a higher Bit Rate.

  • Comment number 62.

    First LinowSat data now showing for VBR, what a disappoinment :-(

    Max 9738
    Avg 7866
    Min 6059

    So after all these months of campaigning for am improvement in bitrate, it would seem the BBC have responded by cutting the rate!

    And we thought 9.7Mbps CBR was bad. It beggars belief.

  • Comment number 63.

  • Comment number 64.

    Would just like to thank BBC HD in advance for ruining many thousands of viewers pleasure. Are the BBC HD team really going to be showing the world cup at such low bit rates???

    Come on Andy, You and Danielle must showly have got tired of you little joke at the viewers expense, youve had your laughs, now surely its time to up the bit rate for the world cup???

    You channel will be a laughing stock, are you really going to want BBC HD completely laughed at for the entire world cup??

  • Comment number 65.

    I watched part of Nature Watch - the close-ups of the butterflies were good but images of the presenters standing in the field where they were watching them weren't good.

    #Post 62

    That is terrible - if 9.7 is the 'highest' rate - it should be the average - so between 8 and 12 maybe

    I agree with nur0 this is a diappointment

    Cheers, daveac

  • Comment number 66.

    @ 65, Its not just a dissapointment, its a disgrace and BBC HD should not be allowed to get away with it.

    The government should step in fast and remove the world cup from the BBC HD channel and let Sky get the rights.

  • Comment number 67.

    Dear all - thanks for the posts - you have to be careful how you read the results of average bit rates after such a short period . Now the encoder is in VBR is allocate bit rate as it sees fit. Wednesday 83 - I can only assume you didn't watch Spring Watch!

    Dear 128fsh - the grass shots would have stretched the encoder - washed out faces are not something it can do.

    Andy

  • Comment number 68.

    Sorry "...Now the encoder is in VBR is allocate bit rate as it sees fit..." should have read "...Now the encoder is in VBR it allocates bit rate as it sees fit..."

    Andy

  • Comment number 69.

    @ 34

    I agree entirely. I cannot see how a frequency grating intended for use on analogue systems has any real relevance to a digital system.

    What would be more useful is an electronically inserted "resolution" grating aligned with the pixel matrix with black and white vertical lines in alternate pixel positions. The grating could contain various resolutions ranging up to 1440 and 1920. This would be a much better guide as to what the encoder is doing and one's own TV receiver performance.

    Also, apart from basic set-up, a static test card design is naff all use on a digital TV system where motion encoding removes picture detail. A moving element, such as "white noise", is required to get an approximate idea of how well rapid picture changes are being handled.

  • Comment number 70.

    @67
    If the grass shots were stretching the encoder, then the peak allowed bit rate is still 9.7.

    @68
    It would be more accurate to say "the encoder allocates bit rate within the parameters with which it has been programmed.". The peak bit rate looks to have been kept at 9.7.

  • Comment number 71.

    Andy # 67

    OK, so what are the upper and lower limits that you have set the encoder to operate within?

    Thanks

  • Comment number 72.

    I would have thought that the purpose of introducing Stat Mux'ing and VBR was so that BBC HD and the forthcoming BBC 1 HD could share the available bandwith more efficiently.

    Rather than 2x channels operating at a fixed 9.7, that should be the average across them, allowing the channels to peak above that when required.

    Can Andy assure us that this is the case, and as asked in #71, tell us what the upper limits will be?

  • Comment number 73.

    What an unbelievable disappointment! Despite all the campaigning and complaints, the BBC's action is to rub salt into our wounds. And now we know why the 'open BBC' never mentioned how imminent switching to VBR was on our visit.

    Andy, to stop us drawing the wrong conclusions, if they are wrong, and if the encoder really can "allocate bit rate as it sees fit" what maximum bit rate has been set for the HD channel on satellite? Can it use the full 8.7 Mbps that has been usefully employed as null bytes since August 2009? Null bytes that is, that were wasted even more yesterday, peaking at 12.5Mbps.

    I suspect the answer is no, as allowing it to peak at higher than 9.7 Mbps and the viewers seeing a better picture, would show that we were right and the BBC was wrong over the bitrate debate.

    Even if you are reluctant to tell us what maximum bitrate has been set, we will all know over the next few days, so how about treating us with some respect and telling us know.

  • Comment number 74.

    Well we have to wait for Andy to reply, but if as suggested by some VBR has been introduced as a mechanism to 'use spectrum more efficiently', rather than improve PQ, then yes that would be an awful disappointment.

  • Comment number 75.

    Well let's see how it pans out over the week, but day 1 of VBR has been a far from auspicious start. We have gone from the too-low 9.7Mbps CBR to the even-lower VBR with that 9.7Mbps as the TOP end & averaging only 7.8Mbps. The nullbytes now reads as 31.3% of tx, & then we have the mysterious audio/data @ 21.1% of tx.

    Interestingly, the HD channel now occupies LESS THAN TWICE the bitrate of either of the SD BBC 1 channels! SD channel = 720 * 576 = 414,720 pixels, (BBC HD's version of) HD channel = 1440 * 1080 = 1,555,200 pixels: HD channel = 3.75x SD channel pixels.

    The HD channel occupies considerably less bitrate than the nullbytes on the tx.

    This we are told is efficient use of available spectrum.

  • Comment number 76.

    Dear all - sorry had to leave early this morning but thanks for all the posts

    A quick run through

    1. Languid05 #69 Although the system is digital, it is just a carrier - the front end of a camera is "very" analogue. I hope the EBU display group will check my proposed post today and as soon as they get back to me I will put it up.


    2. tagmclaren, citizenloz and burnlea. It is not wise to look at VBR stats after such a short period with such a course scale - all it will show at the moment is a change. The limits are outside the lines shown on LinowSat though. Also I have been saying (for several monthe) that we were working on a move to VBR, we did mentioned it during the visit too. In one of my posts I believe I said that just like financial adverts say - with VBR your bit rate can go down as well as up!

    Dear nur0 - but you forget the SD services are MPEG2 and HD is H.264 - so your comparison is not a valid one - if we were to assume a 2:1 efficiency SD would transmit at around 2.25Mbs

    Andy

  • Comment number 77.

    HD1080 Blog 9 part 2

    Why were the tests done only with Plasma HDTVs, when much more viewers will be watching on LCD HDTVs? Is it because Plasma HDTVs hide artefacts more than LCD HDTVs?

    This as been my point of view for along time now as well, The picture
    Quality on LCD screens has differences,ie the picture is brighter
    looking, also LCD screen look sharper ,and when i see problems with
    poor HD Picture Quality it shows up more so.

    To me the tests do at the BBC, are not the ture picture, the best way
    is to do a side by side comparison of the new encoder at higher and
    lower Bit Rates side by side, and the old encoder at higher and lower
    Bit Rates.

    What i would have like the viewers Group vist to have seem is these
    side by side tests carried out on large LCD screens, This would
    add showed up more Picture Problems, and been a better test.

    Yet again the BBC are Hideing Picture Quality Problems on small
    42 inch screens for the main part of the tests.....

  • Comment number 78.

    Andy @ 76
    Although the very front end of a camera might be analogue, I'm actually concerned with the test card image which is created electronically. Frequency-based gratings only have any point when checking the video response in analogue systems. In a fully digital transmission chain, gratings can only have any value at the receiving end if they exactly match the horizontal pixel pitch and sub-divisions of it. Therefore, the gratings should represent, in my opinion, pixel pitches of 1920, 1440, 960, 720, etc. Only this arrangment would allow the end user to check the performance of their display equipment.

  • Comment number 79.

    @76 Andy Quested wrote:

    tagmclaren, citizenloz and burnlea. It is not wise to look at VBR stats after such a short period with such a course scale - all it will show at the moment is a change. The limits are outside the lines shown on LinowSat though. Also I have been saying (for several monthe) that we were working on a move to VBR, we did mentioned it during the visit too. In one of my posts I believe I said that just like financial adverts say - with VBR your bit rate can go down as well as up!

    Andy, just tell us what parameters you have set for the variable bitrates - upper/lower limits and such.

  • Comment number 80.

    Thanks Andy,

    Yes we are aware of potential limitations of looking at the Linowsat numbers. We have no idea how they are sampled.

    Hence the simple question put to you regarding what limits you have put in place. If I rememmer correctly that during our visit you said VBR testing showed peaks between 12 and 13 Mb/s were beneficial to some material.

    Also, we would fully expect with VBR that the bit rate would dip to low levels on un-demanding content.

  • Comment number 81.

    Re: Plasma vs LCD

    Without starting a pitched battle between the Plasma and LCD supporters here I would like to point out that LCD often looks "sharper" because of all the artificial contrast enhancement that goes on in the background to make up for the inherent slow transition between extreme states of the LCD panel. One of the reasons that people with LCD screens might feel that they are seeing more defects (hence concluding that LCD is more precise) is that the contrast enhancement can exaggerate errors.

    That said, the LCD (lowest common denominator) of viewing systems is a cheap LCD (sic) with a huge artificial contrast enhancement, so the BBC should be looking at results on one of those for their worst-case scenario. AQ time to get yourself down to LIDL!

  • Comment number 82.

    Did a comparison between Eurosport HD and BBC HD yesterday for the live tennis from Queen's.

    Couldn't tell the difference. Wasn't the best HD though. Eurosport was running at 14.5mbs yesterday.

    Must be a production flaw.

  • Comment number 83.

    Just a very briefy I'd like to thank Any Q. for continuing to read and reply to 'our' comments and questions.

    Andy - please keep posting and understand our frustration when may of us press for a little more clarity in your replies.

    Of course we understand that a VBR will include 'undemanding' sections where the rate will drop below 9.7 Mbs but the real benefit lies in VBRs being allowed to reach much higher when required by the material - possibly up to double that rate.

    Again I think I can say that most of us realise that hand in hand with VBR is the application of Sat Multiplexing when a 2nd or 3rd channel is dynamically sharing the digital resource.

    After many, many weeks of my hours watching BBC HD shrinking down to a just a handful of shows a week I really hope there will now be a visable improvement.

    Thank goodness my Blu-ray films still look as good as they did a year ago - proving to me a least - that both my TV and my eyes can deliver a great viewing experience when the source is up to it.

    And no Andy - I don't expect Blu-ray performance (with 1080p and very high bit-rate) from BBC HD - I mention it to show that I am - and my TV is - 'capable' of dealing with an increased picture quality if the BBC should choose to supply it to me and others.

    Cheers, daveac


  • Comment number 84.

    Dear citizenloz and tagmclaren - thanks for the posts. It's more that the LinowSat tables will take some time to give a more accurate overview. I will leave answering the limits question at the moment to asses the results without the preconceptions some "other" posters have suggested

    Dear 128fish - thanks for the post. In theory the tests should be carried out with Grade 1 broadcast monitor to factor out any display processing but there are none that are large enough at the moment. Well set up displays (Plasma or LCD) will display the same image content - there may be some difference in motion portayal however.

    Our displays were set to the ITU test standards.

    Andy

  • Comment number 85.

    I have now put the bbc-hd transponder on my 24h monitoring list. Now the results are more accurate. This was not necessary before at the time of static bitrate multiplexing.

    You see the 24h measurements on a timeline chart on my startpage in a slideshow with other charts. After a sometime (depending from the content) you should see the max/min limits.

    I've just startet this measurement. So don't be confused by the limited data in the chart.

    Regarding the question concerning the huge amount of data bitrate I just can tell you that there are more than 200 PID's in this transportstream. Most of them are carrying data with the 'private data descriptor'. I guess it has something todo with 'Red Button' applications. But I don't know. I don't have a freeview box here in germany.

    Oliver

  • Comment number 86.

    Thanks LinowSat

  • Comment number 87.

    Thanks again LinowSat. I should have checked your site before posting :-)

    You can now see the BBC HD bitrate unfolding over 24hrs, right on the LinowSat home page. http://linowsat.de/

    Well done LinowSat.

  • Comment number 88.

    On the subject of VBR I have seen, when viewing BBC HD over the past 24 hrs, a bitrate as low as 4.4Mbps and as high as 15.3Mbps, via a Hauppauge WinTV-NOVA-HD-S2 internal PC card.

  • Comment number 89.

    Just watched a short part of the Queens Tennis BBC HD (Sat) and not overly impressed.

    The crowd behind the court have a 'painted' quality similar to an 'artistic' effect on a jpeg

    It's better than SD of course but 'good' HD

    Cheers, daveac

  • Comment number 90.

    @89 daveac wrote:

    Just watched a short part of the Queens Tennis BBC HD (Sat) and not overly impressed. The crowd behind the court have a 'painted' quality similar to an 'artistic' effect on a jpeg

    As commented yesterday in 36/37 in part 2 http://www.bbc.co.uk/blogs/bbcinternet/2010/06/picture_quality_on_bbc_hd_a_vi_1.html

    "Is the main camera as well focussed as it could be?"
    "Anything from the net onwards seems distinctly soft."

  • Comment number 91.

    Does anyone else think the tennis is too bright? Could this be affecting the amount of detail we're seeing?

  • Comment number 92.

    With regards to the 1920 versus 1440 debate, we now have the chance to compare the two directly. ITV1 HD is a simulcast of ITV1 London launched some weeks ago, is on the Freesat EPG @ 119 & transmits at 1440. Meanwhile the tx @ 10936 on Astra 2D is in FTA test mode for a new STV HD channel, & an ITV1 HD for Granada - both are currently in the clear & running @ 1920. The channel identified as 4051 is supposedly ITV1 HD Granada, whilst 3855 is STV HD. Developments can be followed on DigitalSpy:

    http://www.digitalspy.co.uk/forums/showthread.php?t=1266597

    Both the test channels have the same bitrate & encoder.

    To tune in on the Humax FoxSat you'll need to go into non-Freesat mode & manually tune on that 10936 tx.

    As its a simulcast a lot of the content on ITV1 HD plus the test channels will be upscaled - true HD content can be identified from the EPG, or the Radio Times.

  • Comment number 93.

    I add the idea that when andy first started talking about VBR, it was
    to improve picture quality, i was hopeing for a min of 12 mbps and
    a max of 16 mbps, The point was 9.7mbps is far to low anyway.

    now i can see yet again the BBC do not care about giveing us the best
    possible HD, it still all about there freeview HD platform.

  • Comment number 94.

    Further to #92, it's easiet to stay in non-Freesat mode to compare. ITV1 HD London is on either 5089 or 5090, & when tuned in 4051 is on 5366 & 3855 is on 5368. On the Humax press Red to get 'My TV', then further red presses will cycle through modes until you get to HD TV.

  • Comment number 95.

    At post 91 HD_fan428 wrote:
    Does anyone else think the tennis is too bright? Could this be affecting the amount of detail we're seeing?
    _____________________________________________

    I was just a couple of streets away from Queen's Club a few hours ago and have to say the light from the sky was very strange - that very intense sort of cloudy light which makes one squint, even with sunglasses.

  • Comment number 96.

    So you will leave the limits question for the time been will you Andy, I wonder why that is... let me think.... is it because the max limit will be a mere 9.7 mbps??? And you dont want to admit this?? Just curious why no one at BBC HD can actually be open and honest when it comes to bit rates and quality.

    BBC HD has the lowest quality of all HD channels available in the UK with the exlusion of Luxe HD. On Friday the World cup starts. Arguable it will be one of the most watched events in the UK and throughout the world this year. Are you seriously going to ruin many thousands (possible a million or so) viewing???

    Trying to get answers which are open and honest from BBC HD regarding quality is like trying to get blood from a stone.

  • Comment number 97.

    Re #92,
    I wonder if that indicates that ITV1 HD will also move to 1920, leaving BBC all on its loansome at 1440?

    Well the BBC and Luxe. I guess that indicates the aspirations of BBC :-)

  • Comment number 98.

    I think I should mention the quality of Queens Tennis. Comparing the Queens tennis to the French open on Euro sport HD last week is like chalk and cheese. The French open looked stunning - the colours were vibrant, the images were sharp and detailed and even on the days when the sky was dull and there was rain, it was excellent.

    The Queens Tennish looks washed out, the cameras do not look focussed and its just poor HD.

    I'm comparing the pictures on BBC HD to Eurosport HD and as youd expect Eurosport has the slight edge. The difference is only slight thanks to the poor production. The net on BBC HD seems more fuzzy than eurosport and the aegon boards look more detailed and sharper on eurosport also.

    Who actually decides who to use for the procution on Sporting events??

    It just beggars belief that a channel that has been running for several years can still get things so wrong.

  • Comment number 99.

    Luxe has gone off air, hasn't it?? :)

  • Comment number 100.

    Andy,
    Thanks for your continued patience with our requests for your information.
    As the fixed bitrate was 9.7 Mb/s earlier and you have now changed to VBR it would be of some use to the viewers to confirm that once the system has been given a chance to settle that the average bit rate will not fall below 9.7
    The viewers will see a benefit from the VBR as the challenging material recieves more bandwidth and you will have kept to the 9.7 average as before so it's winners all round...
    Anything less than 9.7 average and the viewers may feel they've been done up again.
    I'm sure as well as setting upper and lower limits you will be able to configure for average Bit rate so we don't lose out ..
    Please confirm your motive is to improve PQ and not in optimising bandwidth conservation.
    Many would rather have two top quality HD channels than three or four MD
    offerings

    Thanks



 

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