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BBC HD TV: Winding Down from Wimbledon

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Andy Quested Andy Quested | 10:30 UK time, Wednesday, 6 July 2011

Wimbledon was the BBC's first ever 3D TV transmission. Andy Quested writes about the technical details of BBC HD encoders going back to 2D mode.

This morning after a very successful 3D trial the BBC HD Channel encoders reverted back to their “2D” mode.  As a last word on the Wimbledon 3D trials, I am trying to get a series of blogs together from everyone involved, so hopefully more over the coming weeks.

From your comments I know the topic of 1920 transmission is something some of you feel very strongly about. So I thought this would be a good opportunity to do a post about it.  The whole topic is not straightforward or we would have been 1920 from the start of the HD Channel.  Although technology has matured the debate still moves between the science, the technology to produce it, the ability to deliver it and the impact when you see it at home.

As trevorjharris pointed out in the Gearing up to Deliver Wimbledon 3D blog post, the BBC’s HD strategy states we fully support the 1920 x 1080 standard for programme making.  This position has not changed but even though all programmes are delivered this way, not that many are yet made 1920.

In the BBC HD Channel promo for example there are only two programmes acquired and post produced in 1920 and during the time the encoders were set to 1920, the majority of programmes shown were not made in 1920.
One thing to remember is, two of the current primary production formats are not 1920.  Sony’s HDCam tape format is a 1440 3:1:1 format at around 140Mbs and DVCPro100 (DVCPro HD) well – that’s slightly more difficult to define.  It depends on the camera and whether it’s being used as a tape or a file codec.   As a tape codec it is often used in the Panasonic Varicam where it’s used to record 1280 x 720.

The Varicam is one of the very few 720 cameras we allow – its “CV” goes back as far as Planet Earth and Galapagos and it’s still being used for stunning Natural History programmes.  This was one the points I made during the picture quality debates last year.

During the trial we did take the opportunity to look closely at some of the differences on each platform and how some devices handled the change.  I will report back on the findings as we get more information. 
We’re also looking at the impact of the different scaling technologies used.   Good scaling is vitally important, especially when it’s used during programme making. 

If we don’t do it well it can cause aliasing – this was something we had to guard against when we made the Side-by-Side image for 3D.  Similarly up-scaling from 1440 to 1920 in domestic equipment, can also soften the images or a add edge ringing (or both!).  The degree of softening or ringing depends upon the interpolating filters which perform the up-scaling.

We are working on other improvements to the programme and transmission chain including more use of 1920 and hope to have news later in the year.

I will keep you up to date on the work as often as possible.

Andy Quested is the Head of Technology, BBC HD & 3D. He previously wrote to explain 3D TV and the BBC's Wimbledon 3D TV trial

Comments

  • Comment number 1.

    Cheers Andy sounds good to me, great to hear your department will be addressing the resolution increase at some point in the near future, we just got S2 and so will have to wait a little longer for 1920 when all parameters are up to scratch and equal from source to the home and give us once again, one of the best quality HD channels in the U.K

  • Comment number 2.

    CGI based and live programming should of course all be 1920.

    It would be nice to think that in the not too distant future there may be a BBC related item like this:
    http://www.sgo.es/eventsnews/news/item/onsight-is-nominated-for-an-ibc2011-innovation-award-for-stereo-3d-post-production-of-flying-monster/

  • Comment number 3.

    Andy can you explain why most other HD channels that are available are using 1920? Do you believe they are all doing it wrong and the BBC is correct in not adopting it?

  • Comment number 4.

    Dear Gary Sargent - thanks for the post. I'm sorry I can't and don't comment on other channels but as I said the topic is not a straight forward pixel count.

    Dear Kit Green thanks for the post - 100% CG programmes would indeed demonstrate a difference but any live action mix would change that position

    Dear soul4real - many thanks for the comments I am sure there will be much debate here!!

    Andy

  • Comment number 5.

    First of all thankyou to Andy for letting us discus this. You say

    The whole topic is not straightforward or we would have been 1920 from the start of the HD Channel and although technology has matured the debate still moves between the science, the technology to produce it, the ability to deliver it and effect to the viewer.

    Why does the BBC have problems with 1920 when every other HD broadcaster in the UK transmits 1920?

    I cannot see why scalling is an issue as most domestic televisions are native 1920 and have to upscale from 1440 in any case. Surely the BBC can upscale to a higher quality than domestic equipment. There is pleny of high quality scaling equipment on the market.

    During the trial BBC HD certainly looked alot better to me and I can see no reason for not keeping 1920. You increased the average bitrate by about 2Mb/s but even so this is still too low as mosquitoing was clearly evident.

    One of the problems with profesional equipment is that it becomes obsolete before it wears out. I can understand the BBC's reluctance to to ditch all those obsolete cameras but I think this is a price broadcasters have to accept. In any case there are alot of programs not produced by the BBC in 1920.

    What Satellite's July issue has an article on "Hi-def failings exposed" should make an interesting read.

  • Comment number 6.

    Dear trevorjharris - thanks for the post. This seemed a very good time to air the subject without the danger of going off topic.

    Can we agree there is a very big difference between sending a 1920 signal and displaying a 1920 resolution image? To take the most obvious example, we can send an SD image in an HD signal but it contains no more resolution than the original image had. With HD you also have to remember there are filters to prevent ringing and alias that have to sit inside the systems frequency - have a quick look at http://www.bbc.co.uk/blogs/bbcinternet/2009/03/bbc_hd_nyquist_limit.html

    Bottom is - you cannot send a 1920 image through a 1920 chain and display it on a 1920 display if the image moves

    Shame but true - Kit Green was spot on with CGI though, if everything was pixel based there would be a very noticeable difference - assuming a relatively perfect chain from use to you. A risk of being provocative - the DOG did look sharper - or would have at lower transparency!!

    As for cameras, it's not just the camera. Most cameras have 1920x1080 sensors but the codec used for recording. These are going to be with us for some time but as tape dies we will see less and less of them being used.

    The new cameras with sensors above 1920x1080 are far more interesting. I hope the next generation of camera will all have sensors with pixel counts well over the current HD standard that we can record then use to get a higher resolution image through.

  • Comment number 7.

    Dear trevorjharris - sorry typos above - "Bottom is" should be "Bottom line is" and "chain from use to you" should be "chain from us to you" and finally "codec used for recording" should have had "is not always 1920" on the end

  • Comment number 8.

    Just out of interest Andy which programs broadcast during the trial period were made in 1920? I imagine family guy would definitely be one

  • Comment number 9.

    Thanks for the reply. First let me say that the BBC transmitted 1920 for several weeks with an increase in subjective quality . So all the arguments you put forward are rather achademic but they can be easily dealt with.

    First let us deal with the Kell Factor to which you refer. For the sake of argument lets us use a kell factor of 0.8. This means that the effective horizontal resolution of a 1920 picture is 1536 pixels. If we now take this and down sample to 1440 the kell factor now reduces the horizontal resolution of 1152. My point here is that 1920 will result in a higher resolution picture assuming that the source is 1920. If the source is 1440 there would be less advantage.

    There is however another good reason for going with 1920 and that is the use of the HD-SDI interface. HD-SDI is the universal standard for digital transmission of video along coaxial cables. HD-SDI does not support 1440 and so a 1440 signal must be upsampled to 1920 for this interface. For live television this is universily used and so whatever the sensor size it must be upscalled. Actually other formats are supported but not 1440. I have no doubt the BBC HD infrastructure is all 1920. Even if the feed is not live and taken from tape the video playback machine will use an HD-SDI output.

    This 1920 video passes though the system and is evenually fed to the encoders which down sample to 1440. At the recieving end the 1440 is then upsampled to 1920 for display on our tv screens.

    To sum up at a minimum the video is upsampled twice and downsampled once. Hence it is no wonder we get a grotty picture. If the BBC changed to 1920 only a maximum of one upsample would be need.

    As Andy implies sampling degrades the picture and so should be minimised.

    The only reason the BBC may wish to keep 1440 is that masks the fact that BBC uses obsolete tape systems as it would be obvious when this old equipment is being used.

    Actualy higher definition cameras are available like the "Red" cameras which go up to 5K.

  • Comment number 10.

    Can I just say, the tone of this post and the comments is encouraging. i'm sure a lot of the bad feeling often comes from a sense (justified or not) of being ignored or shut down. Feeling that there's ongoing engagement on these matters is much nicer, and I hope you feel it's worth your time to keep the outreach going. :-)

    I'd forgotten about the change *up* to 1920 until I saw Springwatch that night and there was a segment (tellingly perhaps, shot by a third party) that fairly popped out of the screen. The improved picture quality was immediately apparent. A quick check on my pvr software confirmed the 1920 signal was being transmitted.

    As time went on during the trial, I have to admit that for a lot of the material the difference between it and BBC One HD wasn't so apparent, and as you say this is probably a limitation of the capture stage - ie: the cameras and other equipment providing the source material. And so if the decision is largely controlled by the amount of material being broadcast that would benefit from the resolution upgrade, then it should presumably be self-correcting as the higher quality equipment filters down to more production departments and companies. And presumably at some point a threshold will be passed where it becomes worthwhile.

    Anyway, I'm recording a cycle of Preview now to compare with the cycle I recorded during the trial, and will compare. :-)

  • Comment number 11.

    9. At 14:32 6th Jul 2011, trevorjharris wrote:
    Actualy higher definition cameras are available like the "Red" cameras which go up to 5K.

    Red itself does have some strange problems of its own, including their definition of what 5k (or any other options they provide) really means.

    I am sure you would not like to post produce directly from a 5k image stream with even the most up to date professional gear. The main problem being the ever present (since the dawn of TV) problem of data storage and manipulation. The goalposts keep moving.

    Remember that even in "traditional" HD post production (except low budget) the images should be processed at 1920 uncompressed so any image manipulation will create new true 1920 output which when mastered to HDCam-SR (as required by the BBC) will retain its full resolution.

    HDCam-SR cannot yet be described as an obsolete tape system. You must be on about HD-D5!

  • Comment number 12.

    Dear all qucik answers as I am away until tomorrow late pm

    Dear trevorjharris - thanks for the post. Can I just say the BBC like the rest of the industry use the two codecs mentioned for a lot of programmes. We own only a few Varicams for Natural History but the rest comes from the same market as every one else.

    Can I remind you of your conversations with Alan Roberts about Kell and camera resolution starting with his post 352 in the third Paul Eaton blog http://www.bbc.co.uk/blogs/bbcinternet/2010/06/picture_quality_on_bbc_hd_a_vi_2.html

    As for single sensor cameras please remember the Bayer filter and the processing done to produce a video signal - more on these cameras later though when there's more time

    Dear NSM_HD - the live sections of live programmes - odd thing to say but many live programmes include pre recorded or time slipped sections.

    Dear StrangeNoise - thanks for the post. I am a bit confused by "third party" do you mean the OB company or the production company?

    Dear Kit Green - thanks - will catch up with this later

    Andy

  • Comment number 13.

    11. At 14:58 6th Jul 2011, Me.

    I should of course have written that HCCam-SR will record the best you can on tape, there is still a degree of compression.

    The only way to get totally uncompressed 1920 4:2:2 is to run it from high performance disk arrays, but what is the point (except in post) as you cannot do anything with it in the broadcast or web environments.

    Even digital cinemas use compression just to make the data handling possible.

  • Comment number 14.

    This post is very reassuring to me. I do believe 1920 would be better, as long as you can secure the necessary bitrate increase. I noticed during the trial, many scenes looked better (even ones from 1440 sources, as I believe the fact that you were upscaling them rather than my TV helped quite a bit). However, water (the hardest thing for h264 to encode, I do believe) quite often looked slightly worse than it did in 1440, implying not quite enough bitrate.

    And yes, I did actually notice the DOG looked better in 1920!


    So, in conclusion, I'd like to see a change to 1920 if, and only if, you can get enough bitrate to make it worthwhile.





    Oh, and out of interest, if you happen to know - what's with the encrypted ITV1 HD region on your satellite transponder? Have they got a deal with Sky which means they have to have certain regions encrypted or something? It seems rather odd, is all - I mean, they're on Astra 2D, on your transponder - why don't they make it FTA?

  • Comment number 15.

    I would like to make it plane that what I described in post 9 has nothing to do with camera resolution. I am only considering the degradation of picture quality at the SDI interface. I deliberatly did not want to get into discusion about the BBC's antique camera collection.

  • Comment number 16.

    Muzer0, i believe sky's contract probably has something to do with encryption, i believe there is an unencrypted version and an encrypted version which merely points to the unencrypted version in order to not waste twice the bandwidth.

    In regards to picture quality, andy was talking about 1920 not being much better than 1440 especially when the source is 1440, thats true if the bitrate remains the same but if the bitrate is increased then that isn't true. Your cameras likely have 40mbps+ bitrate that they record in so the quality would be increased alot.

    The picture quality increase during the 3d trial was very large, i just wish it was like that all the time.

    I assume by your post a decision has been made to use the additional capacity of DVB-S2 to increase the resolution and bitrates on BBCHD/BBC1HD at some point over the next few months?

    How much extra capacity is there on the Mux now? enough for increased resolution and bitrate for both channels and an extra channel? BBC2HD would be incredible if that could be added. Shows like Mock the week and other in-studio shows would cost peanuts to air in HD. I'd presume you can't launch BBC2HD until there is capacity on Freeview HD for another channel (after the switchover finishes in 2012)?

    Why are the BBC still using 1440 cameras in 2011? Surely the BBC would make more money by making shows in 1920 which can be licensed to foreign countries?

    I can understand if camera for each of the 100's of journalists aren't 1920 as that would cost alot but why aren't all the in-studio cameras 1920?

  • Comment number 17.

    16. At 08:43 7th Jul 2011, hajj_3

    It is more than likely not the cameras that are the limiting factor regarding 1440. It is the recording technology and possibly some older parts of the signal chain.

    Don't forget that there is no uncompressed transmission so there is every justification to effectively limit bandwidth during production as this saves money on kit and time in image rendering.

  • Comment number 18.

    Dear hajj_3 thanks for the post. First, re the DSat multiplex can I ask you to comment on Alix's S2 blog?

    Other than poor scaling there is an advantage to using 1440 (see the Alan Roberts comments I mentioned in #12)

    A quick note - other than the Varicam used for Natural History because of its flexibility for variable frame rate shooting, almost all cameras have 1920x1080 sensors. Not all codecs record 1920 though (again see Alan Roberts' comments).

    The current codec requirement for cameras is a minimum of 50Mbs MPEG2 long GOP or 100Mbs i-Frame. DVCPro100 is 100Mbs but is primarily a 1440 or 1280 codec 4:2:2 in tape cameras and HDCam is around 140Mbs 1440 3:1:1

    We - like the rest of the industry use cameras suitable for the job and although the move away from tape to file is helping us move to 1920 recording format you cannot get 1920s worth of resolution through a 1920 system to a 1920 display.

    Andy

  • Comment number 19.

    @Andy Quested; sorry, by "third party" in respect of Springwatch, I mean it was one of the segments made by independent wildlife filmmakers which Springwatch was featuring in a guest slot on the show.

  • Comment number 20.

    Andy Quested wrote "up-scaling from 1440 to 1920 in domestic equipment, can also soften the images or a add edge ringing (or both!). The degree of softening or ringing depends upon the interpolating filters which perform the up-scaling."

    Yes, this does seem to be true - the difference between STBs is greater with 1440 content than 1920 content, because what you're watching is a result of the STBs scaling algorithm.

    To me, this sounds like an argument for broadcasting 1920 where you have the bandwidth - to remove one unknown in the chain - even if you know the content has already been through one 1440 bottleneck.

    Obviously
    1920 sensor > 1920 capture > 1920 delivery > 1920 broadcast > 1920 display
    is ideal, but currently you usually have this...
    1920 sensor > 1440 capture > 1920 delivery > 1440 broadcast > 1920 display
    ...where that second trip through 1440 is _not_ benign.

    Of course where you have this...
    1920 sensor > 1920 capture > 1920 delivery > 1440 broadcast > 1920 display
    ...the trip through 1440 is damaging, no matter how perfect the scaling is.


    btw, tou keep saying this...
    "you cannot get 1920s worth of resolution through a 1920 system to a 1920 display"
    ...and I understand the technical argument you're making - but by the same argument, you cannot get 1440s worth of resolution through a 1440 system to a 1920 display either - the number of pixels you have never resolves that many lines in motion - but following that argument to its natural conclusion would mean broadcasing SD, or no pixels at all!

    Plus the broadcast chroma resolution is already well below what a broadcast quality camera captures - you are throwing away real genuine chroma detail by downscaling - albeit detail that human eyes are less sensitive (but not entirely insensitive) to.

    I guess 1920 won't have the capacity to be pixel-sharp until cameras are oversampling and filtering electronically. But it would be a real shame to stick at 1440, with all the downsides in consumer scaling, encoding, and lost resolution until that day!

    Cheers,
    David.

  • Comment number 21.

    Andy, As is my understanding, you use 1920 internally at your payout centre why would you want to down sample this to 1440 for it to just be up sampled by our receiving equipment, as per the trial as may other people have said the picture was better at 1920 even with 1440 originated programs, although saying this the picture looks better on my cheap freview hd box compared to my Sky+HD box which seems softer, so maby the freeview equipment can up sample the 1920 image better than on DSat.
    A bit off topic, i found what seems to be BBC HD on a Eurobird transponder [11508 MHz, Hor, QPSK] under service 1 and according to linosat it is still at 1920, i was just wondering what it is?

  • Comment number 22.

    I see Andy is determined to make this a camera issue when I showed in post 9 that it is not only a camera issue.

    First of all I think we all know that you cannot get 1920s worth of resolution through a 1920 system to a 1920 display. In fact that is not true for CGI just look at Sky News HD they get crystal clear graphics at full 1920 resolution. The point is YOU GET A HIGHER RESOLUTION THROUGH A 1920 SYSTEM THAN A 1440 SYSTEM. Sorry to shout but this is point. Even material sourced at 1440 would look better as it would not have to go through the down conversion at the encoder and the up conversion at the receiving end.

    There are advantages of using 1440 and that is a lower bit rate and it might help to reduce noise on a noisy source. But all this is at a cost of lower resolution.

    Some cameras with 1440 recording systems have 1920 sensors. This means that the 1920 SDI output can be fed into a portable recorder to preserve the resolution.

    It was quite clear that the BBC HD output benifited from 1920 during the trial so the argument over cameras is not realy an issue.

  • Comment number 23.

    Dear trevorjharris - thanks for the post and yes you have it! There will be a difference on CG material. Unfortunately the real world isn't pixel based. As I have said before - other than the cameras we use for some natural history programmes, they are all 1920 but the codecs may not be. Re your shouty point I have to send you back the conversations you had with Alan Roberts

  • Comment number 24.

    At the end of the day though, on Freesat at least, 1920 looked better than 1440. The amount of difference depended on the content, the STB, and the display - but it never looked worse!

  • Comment number 25.

    Andy, just noticed now 13:47 the white dot has re appeared have you done an update on the vison mixer again?

  • Comment number 26.

    Thanks for fixing the white dot Andy! have you changed anything else on BBC HD as the PQ looks better since this morning?

  • Comment number 27.

    Dear NSM_HD thanks very much - percussive maintenance undertaken and successful

    Andy

  • Comment number 28.

    Dear Dear NSM_HD bit of delay in the system - no changes (other than the white dot popping up).

    Andy

  • Comment number 29.

    I am a great fan of percussive maintenance.
    It is the local knowledge of precisely where to kick, hit or stroke a specific item of kit that makes it imperative to have employed full time staff rather than freelancers.

  • Comment number 30.

    Andy, Just been comparing the testcard, as i recorded during the 1920 period, your SUT-BBCHD Preview which included the testcard, and found that their was a significant difference in the bottom two squares on the right hand side those squares in particular the second from the bottom was much sharper in the 1920 one and on the 1440 one it is very soft so appears grey and you lose the lines. This is a good example in showing the difference between the two resolutions, i am not sure if it is the way the sky box up scales the 1440 image or not.
    Using this I was able to diagnose that the "1" service on the eurobird transponder must be 1440 as well, even though linosat is reporting it as 1920!

  • Comment number 31.

    Andy, sorry off topic but not sure if you are aware of this, but on BBC One HD when the sound changes from DD 2.0 to DD5.1 there is a loud but short burst of static, this happens when the news changes to its regions and it changes to the caption (which is in DD5.1). I dont have this problem with BBC HD.

  • Comment number 32.


    Dear Kit Green - Ah! I didn't mean the equipment - more the person who didn't check - same outcome though so I suppose it counts

    Dear NSM_HD thanks - the SUT T/C was a copy for audio ID but as a static image would have shown one more block of the gratings but have a look at the nyquist blog http://www.bbc.co.uk/blogs/bbcinternet/2009/03/bbc_hd_nyquist_limit.html just in case what you see is alias

    Re audio, I will listen - how long have you noticed this for

  • Comment number 33.

    Thanks Andy, I have noticed this for a few weeks now and I am listing through a Sony STR-DH810 via Coax digital audio cable connected to a SKY +HD box. It is quite scary and makes us jump as your not expecting it! BBC One HD is the only channel it happens on.

  • Comment number 34.

    Dear NSM_HD - it sounds like raw Dolby E. We have not had any other comments so I will pass the information to R&D

    Andy

  • Comment number 35.

    Isn't it odd that we are being allowed to discuss HD quality when it's been off topic for so long.

  • Comment number 36.

    Dear Gragix - thanks for the post - not odd I said in post #6 "Dear trevorjharris - thanks for the post. This seemed a very good time to air the subject without the danger of going off topic..."

    Andy

  • Comment number 37.

    Oh Andy you keep on about Alan Roberts. His main argument was that camera resolution was so low that there was no benifit in going to 1920. Actually even his own measurements showed that there was benifit in going to 1920 on some cameras. He produced some niffty circular resolution charts.

    His assertions are no longer true. The Panasonic AJ-HPX3000 has a resolution of 1000 lines which means it can resolve 1777 horizontal pixels. Camcorderinfo measured the HDC-TM700 consumer camcorder also to have 1000 line resolution at 1080p60. That was measured with a moving test card! As for film that is often scanned at 4k or 8k so will definitly benifit from 1920.

    Again it was clear from the trial that 1920 gave a significant improvement in resolution. The BBC is the only UK HD broadcaster not using 1920.

  • Comment number 38.

    Andy, just been experimenting with two Severn second clips of Luther, one from BBC One HD(1440) and the other from BBC HD(1920), I used my vision mixing software at both the start frames fading between the two to compare and there is a noticeable loss of detail on the 1440 one and the 1920 defiantly looks better.
    I am not sure if Luther was made in 1920 or not but either way there is a difference.
    So I defiantly think there are advantages in transmitting in 1920.
    Also, could you shed any light on the "1" channel I found on the eurobird transponder which is currently showing BBC HD, albeit out of sync and if this is to test a new encoder?

  • Comment number 39.

    Ok take a look at this test of the Panasonic HPX317 done by Alan Roberts:

    http://www.trickboxtv.com/wp-content/uploads/2011/04/BBC-Panasonic-HPX371-Test.pdf

    In section 2.4 he says:

    With factory settings, the result for progressive 1080 is
    good, there is no aliasing, and resolution nicely
    reaches the Nyquist limits at a low level, indicating
    either that there is proper optical filtering in the
    camera, or that the lens is providing the limit. The
    lens aperture was F/2.8, usually optimum for an
    HDTV lens.

    Reaching the Nyquist limits means that this camera will certainly benifit from a 1920 transmision system.

  • Comment number 40.

    39. At 10:47 8th Jul 2011, trevorjharris wrote:
    ..the result for progressive 1080 is
    good, there is no aliasing...


    I am sure in the past Andy has shown his old school TV credentials by preferring interlaced material wherever possible, or did I misunderstand?

  • Comment number 41.

    @NSM_HD
    There is an international version of BBC HD with older programmed for eastern Europe and probably RoW. See bbchd.com

    Note that in the Benelux we do receive legally the British version of BBC hd

  • Comment number 42.

    Dear trevorjharris thanks for the post and I can only recommend a bit of reading on the subject before we continue. I will say again we were discussing codecs. As you mention cameras - they are selected for the ability to cover the subject. You should also read the reports I commissioned of the other cameras

    Dear NSM_HD - Luther was indeed shot with a large image format camera with a resolution greater than 1920x1080 and therefore, clearly demonstrates the difference and is the core of "you cannot get and 1920 image through a 1920 system to a 1920 display". What would have shown a greater difference would have been a display with a resolution greater then 1920x1080. This type of camera development is exactly why we are looking coders enhancements to get more of the resolution to home

    Dear Kit Green thanks - I prefer P material but at 50fps or preferably much higher

    Dear Piet Boon - as far as I know only the UK DTT and DSAT services use the current latest generation of encoders

  • Comment number 43.

    Andy, on freeview HD you now have dynamic i/p switching, is there any plans to implement this on DSat, as I was doing some comparisons and the PQ on Freeview HD does seem better than SKY HD.
    I am not sure if this is down to the scaling chips in the STB's or the i/P switching on Freeview HD.

  • Comment number 44.

    Dear NSM_HD thanks for the post. There were some compatibility issues with 3D and I/P switching but this came back again on Wednesday. We hope we can add it to satellite but it's not possible at the moment. What do you have a Freeview STB or integrated TV?

    Andy

  • Comment number 45.

    Andy, I have a Technika STBHDIS2010, and although it only cost me £30 it does seem to produce a better picture on my lg 42LH3000 TV than my SKY +HD box, on the BBC HD channel although does not seem to want to produce DD at all(though you cant have everything for £30!).
    This is making me think that the picture quality on BBC HD (& One HD) is very dependent on what STB/Tuner you are using and how good (Or not) it can scale 1440 to 1920. This is why I believe particulry for DSat, it might be better transmitting 1920 as to produce a more consistent picture quality as the STB/Tuner does not have to do any scaling, as i am sure your scaling equipment is much better than any of our domestic equipment.

  • Comment number 46.

    Dear NSM_HD - thanks - have you checked the STB firmware - from a user group forum...

    Unit arrived today with STBHDIS2010_0133 firmware. I immediately updated it with STBHDIS2010_0161 on a USB stick downloaded from http://www.ch-zero.tv/support Everything works perfectly with no complaints....

  • Comment number 47.

    Dear Andy,

    I do love your r&d talk here, but is to technical for me. Therefore, I regret that the Open blog has now closed for the weekend. On that blog, end users like can give you the real feedback that counts.

    Please open it.

  • Comment number 48.

    Dear Piet Boon sorry but the Open Blog is not mine to open or close. This blog is open to all comments about the encoders change back to 2D settings no matter what (technical or not)

    Andy

  • Comment number 49.

    Andy,yes that's the first thing I did and after the update the box runs perfectly (except for the lack of Surround sound, only LPCM via HDMI/ Coax)
    I have had Sky+HD since march last year and as I live in the central region Freeview HD has only recently (April) become available.
    I was nieve in thinking that the picture quality of BBC HD/BBC One HD was better on Dsat via a Sky+HD because of the reputation of the SD channels on Freeview (Which is why I got Sky). So when I bought my first freeview HD box (because of the good price) just as test box to see what freeview HD was like, I was shocked that the picture looked better via Freeview HD even on an indoor Arial with not the best signal.
    As I understand this may be a common seniro:
    Camera X has a 1920 sensor, and a codec recording @ 1440
    The 1440x1080 recording may get delivered to the playout area in 1920x1080 or remain 1440x1080.
    Internally you have to use 1920x1080 as HD-SDI does not support 1440.
    So assuming it is delivered to you in 1920x1080 then this is the chain the image goes through:
    1920--->1440--->1920--->1440--->1920
    Censor in camera-->Codec in camera-->Processed for delivery/HD-SDI signal internally-->Downscalled to 1440 in encoder for delivery for transmission-->Upscalled to 1920 by STB/In built tuner to display.
    I am sure you had good reasons to use 1440 when you launched because the encoders/codecs were not as efficient as they are now. Although as they are now very efficient their should be more interest in switching to 1920 as I have said before this ensures that the picture is more consistent between STB's as only you will do any scaling your end.
    To bring home the point i am trying to make, yesterday I watched Food Fighters on BBC One HD which at the time I thought wow that is a good picture! then later on in the evening I watched Next Door Nightmares off Sky anytime HD and this knocked spots off Food Fighters, perhaps if it was Tx in 1920 it would look as good as Sky.
    Nathan

  • Comment number 50.

    Dear NSM_HD thanks for the comment. Taking a the audio first - this is probably an AAC/Dolby issue. I will ask R&D if they know about this one

    Re your first 1920-1440-1920 this is all in camera and the front end is analogue so it is more analogous to over-sampling. The image from the camera output does not contain any more detail than 1440. The end process is then a balance between errors inherent in digital systems and quality of scaling.

    Now we are beginning to using better front ends, especially camera sensors that can deliver a properly over-sampled input we can begin to move that through the chain to the set-top box. As we get upgrades working and tested we can get them out. The I/P switch is on of these improvements.

    Re Food Fighters - which programme as I don't think it was in last nights schedule

    Andy

  • Comment number 51.

    Sorry Andy, but this blog just sounds like the usual BBC HD spin and excuse. The fact is, when BBC HD upped the resolution to 1920, the picture was considerably better. FACT. You cannott get away from that fact.

    You can make up all the excuses in the world, but at the end of the day the BBC HD Channel proved that the increase to 1920 gives an overall better picture.

  • Comment number 52.

    Dear wednesday83 - thanks for the post. As you've read in previous comments by me and by others it is not a straight forward comparison. Comment 45 is very telling.

    With new higher resolution cameras appearing, this is something we are working so we can deliver their potential resolution through to the STB.

    Andy

  • Comment number 53.

    @ Kit Green # 11:

    Quote: "Red itself does have some strange problems of its own, including their definition of what 5k (or any other options they provide) really means.

    I am sure you would not like to post produce directly from a 5k image stream with even the most up to date professional gear. The main problem being the ever present (since the dawn of TV) problem of data storage and manipulation. The goalposts keep moving."

    Why?

    I don't know of any problems with 5K conversion provided you have up-to-date pc's. In fact modern pc's can handle some very large video conversions when you get into server configurations with banks of high speed processors, hundred of GB of RAM and terrabyte drives. I'm quite sure non of this is beyond the BBC's capabilities.

    For the record, Red cameras go from the Scarlet up to the Epic with a 28K sensor!!

    I've long be advocating Red as a possible camera manufacturer for HD use at the BBC subject to necessary investigations as to them meeting their purposes. Some people have said their studio cameras but the Scarlet certainly doesn't look that way to me. In fact it was actually designed for outdoor use. Red once upon a time mentioned it as a possibility for soccer mums although given the price, I guess that might only be in Chelsea!!

    Definitely something the BBC should be exploring as it seems from programme to programme there can be some big differences in sharpness and colour from cameras which range from sharp and punchy (often BBC Natural History Unit Cameras) to soft and relatively flat. It should be mentioned here that post production plays a part also.

    Andy re: your comment about post #45, I believe you are giving this too much importance. Unless you know both TV's were properly calibrated to TXH II or above then the fact that one appears sharper on upscaling means nothing as it could simply be down to tv adjustment.

    Also, its long been know that LCD is natively sharper than plasma. Does that mean that a sharp picture on LCD is correct or a blurry one on plasma? No. Because if properly calibrated both tvs should be equal...and herein lies the rub. The BBC need to broadcast to a calibrated standard as with everyone's tv being different, its the only way of achieving a constant. If that means some LCD's appear over sharp, then so be it. The time has come to place the onus on owners of tv to calibrate their systems if they don't like the picture rather than blaming the broadcaster. Once calibrated its blame away as all being equal only the broadcaster is at fault but I repeat the ONLY way to achieve any consistency is to broadcast a signal designed to display correctly on a properly calibrated tv of any type and then if someone isn't satisfied with their picture, let them calibrate away.

    Equally, in the absence of calibration, you can't blame the upscaler as you simply don't know which was to blame for the poor picture on the more expensive tv when upscaled. It could have been anyone of a number of user adjustable settings.

    There are also some good points made above about bit rate. You can't introduce 1.5 times as many pixels by increasing resolution from 1440 to 1920 without increasing the bit rate substantially also, otherwise the compression level has to rise and so does the softness and artefacing correspondingly.

    In fact there's a very good example of insufficient bit rate on BBC SD at the moment - the England Womens World Cup match vs France on BBC 2. Shots of the crowd in the stadium in the background are riddled with artefacts caused by bit rate starvation.



  • Comment number 54.

    Dear Alsone. Thanks for the post and thank you very much for introducing the topic of calibration. We have used the EBU standards since the beginning of colour and the testcard is still the correct calibration tool.

    5K images would be brilliant if we could process them - assuming 5k for Y and 2 x 2.5 for CrCb - the files would be enormous - drama with a shooting ratio of between 10 and 15:1 could possibly cope but the rushes storage alone would huge. Some documentaries at 40 to 50:1 (or sometimes, a lot more) just wouldn't happen at the moment

    However we don't need to go as far as 5k files, sensor oversampling - providing the downsampling is done well would work very well

    Andy

  • Comment number 55.

    Andy,

    Maybe some Red Post production Myth busting is needed here for both yourself and Kit Green.

    Very nice real time video here of Red execs demonstrating the editing of Red Epic files before your very eyes on camera!

    http://vimeo.com/reddigitalcinema/mythbusters

    I can't claim to have used a Red myself, but no signs of anyone struggling!

    It's actually a very interesting video when it gets going. From 4K studio shot to 2K cinema projection in 4 minutes including colour grading, demonstrating editing in 3 different programmes - Avid, Premiere and Final Cut AND viewing on an iPad whilst on the move, all before that 4 minute 2K projection!!!

    I see they also mention the new film The Hobbit is being shot entirely on Red Epic.

    Finally, when you talk about long term storage, I would presume that the BBC would save the converted final cut version of a programme and not the original so for now, until SuperHiVis arrives, long term storage should be no worse than for current HD programmes.

  • Comment number 56.

    Dear Alsone - thanks for the post and link to the video - what more can I say except ask you re-read post 54.

    Andy

  • Comment number 57.

    I now have 2 copies of Top gear episode 2 on my Samsung Sky HD box. One from last Sunday and one from last night. Would someone from BBC HD like to come round and view them??

  • Comment number 58.

    Andy, In relation to the pic quality, What do you think of Eastenders? Do you think this is actually HD?? Also What kind of HD cameras are used?

  • Comment number 59.

    Dear wednesday83 - thanks for the posts. Eastenders primarily use Sony HD cameras. As yet it's not 100% HD as we said when it started. If by "Do you think this is actually HD??" you mean does it meet the criterial and look of an HD programme, the answer is (other than the scenes that aren't HD), yes.

    I have the same two Top Gear episodes and again, other than content and stat mux differences they look remarkably alike

    Andy

  • Comment number 60.

    55. At 10:01 10th Jul 2011, Alsone

    I have worked on post special effects shots from Red, going back to the days before the codecs were released onto anything other than Apple kit. This made it a pain as I was using bespoke equipment and had to wait for slow conversions via red cine.

    Luckily that workflow is a thing of the past.

    The demo you link to is a staged PR exercise. That does not detract from it being genuine.

    The Hobbit is indeed using Red in a stereoscopic environment and New Zealand’s Park Road Post Production have some seriously powerful kit to handle the data rates and toolsets required. This is far more complex stuff than Avid, Premiere or Final Cut (Version 7 or X, that is another current story off topic for here!)

  • Comment number 61.

    @ Wednesday 58, Eastenders looks far from HD to me. In fact I find it very difficult to discern between the SD and HD versions, so much so that I actually find the SD more palatable on the very rare occasions I watch it (this afternoon by strange co-incidence).

    I'm sure Andy will tell you its artistic look. To me its just plain poor hd. Grainy, flat, muted colours, soft picture and with very little to distinguish it from SD. I can kind of accept the muted colours as I guess its part of the gritty depressing look. I find the softness, flat lighting and grain far harder to stomach though.

  • Comment number 62.

    @ Kit # 55, thanks for the interesting comment. I knew it was a staged demo as it is a promo video and the content made it pretty obvious as well. Interesting to note that you don't question the genuineness of the content though which seems to add validity to the preface that Red shouldn't be feared from an editing POV these days.

    Lets hope the BBC explore all options for their camera choice as quite clearly some of the current crop don't produce the vivid sharp detailed HD pictures that many of us like and this will become even more apparent with a shift to 1920 where the resolution is more revealing.

  • Comment number 63.

    Thanks for the Eastenders reply Andy. Can you confirm which parts of Eastenders are actually HD. Very little seems to be HD. Certainly the outdoor scenes are SD.

    Infact, why are you actually broadcasting Eastenders in HD when its not ready for HD? Emmerdale on ITV is not yet HD but looks better upscaled than Eastenders. That should not be happening surely.

    Have you seen how stunning Corrie street looks?? Thats how Eastenders should look.

  • Comment number 64.

    Andy, who actually decides on what production is used for HD programmes. For the BBC to get HD production wrong so many times, there has to be something wrong. I mean which person actually gave the go ahead to let Eastenders broadcast as HD when its not actually ready??

  • Comment number 65.

    its only eastenders guys! :P bbc1hd is a simulstream of bbc1, better to have some bits in hd than none.

    I'd rather they get new cameras for other shows like mock the week than a soap.

  • Comment number 66.

    Dear wednesday83. Thanks for the posts. It seems again you do not like the HD programmes we make so I can't really say more than we already have over the years. Not all programmes will look the same and Eastenders looks good in HD - it looks different because it has it's own style and that is different to Holby or Larkrise or Doctor Who...

    Andy

  • Comment number 67.

    Quote "Eastenders looks good in HD".

    Andy, that made my day. The best bit of comedy to come out of the BBC since Only Fools and Horses!

  • Comment number 68.

    Dear Alsone. Thanks for the post. Now the conversation has reached this level it is pointless to continue.

    Many thanks for the posts and I will speak again in the next blog

    Andy

  • Comment number 69.

    Did Andy just say "Eastenders looks good in HD?". Looks good in HD? Has its own style?? What style is Eastenders actually aiming for? All I see is a blurry SD mess. Should an SD Emmerdale really be just as good if not better than so called HD Eastenders??

    Can I please recomend you google "eastenders picture quality". This may give you an indication of what the quality of picture is really like.

  • Comment number 70.

    @hajj_3 Eastenders maybe a soap, but at the moment its the BBCs flagship show and gets the best ratings overall for BBC1. You would have thought somebody had the brains to realise this and take advantage. But this is the beeb.

    Why do ITV get HD so right in regards to PQ??

  • Comment number 71.

    All other FTA HD channels have got it spot on, and I haven't seen hardly any complaints, but the BBC always refuse to comment on their quality. Also if 1920 x 1080 is not so significant, then why is the european BBC HD version broadcast this way.

  • Comment number 72.

    @71, Totally Agree. Take ITV is a fine example. The picture quality on pretty much most of its shows is top notch. Its flagship show Corrie a fine example.

  • Comment number 73.

    Andy don't take my comment above personally or as an insult, it was just a bit of fun.

    I disagree that Eastenders looks good in HD. If you think otherwise then rather than leaving the blog, justify why you think that it does.

    It would seem that most of the audience here disagree with that assertion so it would be interesting to see why you see Eastenders as good quality HD whilst we don't.

  • Comment number 74.

    Something that really excites us it the appearance of new large image format cameras with pixel counts well over 1920x1080. As these cameras become viable for more programme budgets we will be able to exploit the full potential of 1920.

    Finally, you have all seen me say that HD is about resolution not just sharpness. It is not about edges, it’s about detail. To show what this means you might want to check out the zone plate in the report trevorjharris mentions in post 39 with that of it’s big brother.


    Andy

  • Comment number 75.

    Try again with all the post...

    Dear all. During the visit to the BBC, an ITU test demonstrated beyond any doubt that when presented images in a blind test, the new encoded scored very much better than the old in all but one case. Even in this sequence, chosen to show the new encoders weakness, it scored only a couple of points lower but both new and old scored very close to the original studio material.

    What this is leading to is that it’s very easy to say what is or isn’t good HD when the source is know. However, when presented with the images displayed as required by the standards some of you say we do not conform to, the results say something quite different.

    We always test the impact changes to encoding have on picture quality comparing the new version against the original (and the version of encoder the upgrade is replacing). We’re also very quick to say when we get it wrong as we did with the mix/fade issue.

    One thing that really excites us it the appearance of new large image format cameras with pixel counts well over 1920x1080. As these cameras become viable for more programme budgets we will be able to exploit the full bandwidth of the 1920.

    One thing we do insist on though, is that HD is about resolution not just sharpness. It is not about edges, it’s about detail. To show this you might want to check out the zone plate of the report trevorjharris mentions in post 39 with that of it’s big brother.


    Andy

  • Comment number 76.

    Andy, So what you are saying then is that Even if shows look awful and like SD such as Eastenders, then as long as it as the resolution then thats ok?

  • Comment number 77.

    Thank you very much to Andy Quested for posting and answering question, and to all of you for your comments and questions. Particularly as some questions are repeating, Andy needs to get back to making BBC HD fantastic. I am therefore closing this thread to new comments.

 

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