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The Hitchhiker's Guide to Encoding: Before we start

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Andy Quested Andy Quested | 09:24 UK time, Friday, 4 December 2009

Friday

It's been sometime since my last post on the blog but I have tried to be as active as I could on the existing ones. I read all the posts and my thanks go to Paul Eaton who has listed many of my comments just to prove I do exist! I try to answer points raised in the blogs but unless there is a specific issue, I just can't answer each post individually.

Because there's a lot to say, I thought it would be better to serialise this blog over the next week with each episode covering a different topic. I will make no apologies for the titles and many thanks to the memory of Mr Adams.

Today: Opening and audio issues
Monday: HD encoder history
Tuesday: The EBU
Wednesday: PSNR and all that
Thursday: New encoder evaluation
Friday: Programme styles and closing thoughts

The BBC HD channel is two this weekend and in that short time we have developed one of the widest ranges of programmes you could find anywhere in a single HD package. No one is going to say it's all been perfect and in the past I have had to make a couple of very confessional blog posts when we've "just got it wrong", for example:

BBC HDTV: "The BBC's Bold Trial Of Reverse Karaoke!"
BBC HD: Olympics Opening Ceremony Surround Sound

We take every aspect of the channel very seriously and consider you to be a valuable asset when it comes to problem solving, trouble shooting or just "plain" talking! I'm sure Paul won't mind if I quote a section from Roly Keating's reply to his email:

"...Andy Quested has himself been considering the most recent exchanges on this subject, in consultation with the BBC's R&D teams, and will be posting further messages in response very shortly. Please consider my comments in conjunction with his: I hope that between us we can at least persuade you that we are paying the closest possible attention to the debates on this subject, and working constantly to keep standards as high as possible."

I want to make sure everyone who reads this blog can understand it - well maybe with the exception of the PSNR section that even leaves me with a bit of a headache! But I hope it will be clear enough so first time readers as well as those who have been posting since the beginning have an equal opportunity to comment, so I hope some of you will understand if you find it's going over old ground or in some way is not technical enough.

Before I start, it's worth saying encoder testing takes a long time because it's not just about picture quality. Before any testing starts a new encoder is checked for full compliance with the MPEG4 standards. Then it's tested for a considerable time to make sure it's compatible with existing set top boxes from different manufacturers and with the Sky platform. Then for audio compatibility (surround sound and stereo), for audio description, for subtitles and for interactive services.

Although we test the encoders on as many receivers as possible, we can only commit to a guarantee of compatibility with the supported platforms, so for satellite that's Sky and Freesat. I know several of you use DVB cards in PCs and Macs and have had problems. However there are so many different devices, options, versions and software variables, it's just not possible to check everything and therefore we cannot support these receivers properly. If you do use a DVB decoder card, have a look at this site for more help:
http://thegreenbutton.com/forums/t/73544.aspx?PageIndex=8

The next few days will give you a glimpse of some of the work done to maintain the quality of the BBC HD Channel by BBC Research & Development, our partners and to a lesser extent, me!

So to begin... Audio!

The Holes at the End of the Chain


(Or, why do s the aud o have so many h les)

Back in 2008, Rowan led a detailed overhaul of the HD Channel's audio system to make sure the new AV Sync test signal would really be sync when it arrived at your set top box!

We made sure the Channel's AV sync was within 5ms and we check it regularly to keep it there. The number of complaints about AV sync dropped to virtually zero after the signal was first shown and, with the exception of a couple of live programmes, it's been that way ever since. We've also completed thorough training sessions with all our main service suppliers to make sure they understand the issues of distribution and transmitting surround sound signals and metadata.

Recently though, we've had a couple of weeks where nothing seemed to work properly. It started with holes in the audio during Strictly Come Dancing. Your posts suggested they were on satellite and cable, so the investigation started in Television Centre. I was convinced it wasn't the right place to start, call it professional pride but we had gone through the chain pretty thoroughly, and as I said, it's checked regularly.

So I kept listening and a couple of days later I heard holes during the live Later with Jools and in the promo but this time they were much smaller. I asked our playout people to keep repeating the clip in the promo while we listened on every receiver we could find.

This proved the holes were only on the satellite output and we quickly tracked the problem to one of the HD Channel's "resilience" circuits. As soon as it was isolated, the holes stopped. We knew what had caused the problem but are still investigating why!

For 48 hours we had nice clean audio but just when I thought I could breath again and we had audio under control it promptly failed again, not once but five times!

As the first Electric Prom went to air the holes reappeared. I was watching at home so was on the phone in about 10 seconds. This time the play-out centre could hear them and they sounded like the surround signal was not synchronous with the video reference.

The Channel director went to emergency cut mode that removes all play-out processing, stopping the holes but not curing the problem. While we investigated, I decided we should use the reprocessing unit in the central switching area put in after the 2008 Eurovision Song Contest. This cleans up signals and modifies metadata if required, before transmission. It solved the problem for the next transmissions but we had not identified the cause. Timing issues are notoriously difficult to track down especially in mobile systems, but we will find it!

There was another audio problem during Thursday's prom. The programme started well but I had been warned it would be edited on site and it would be very tight to transmission, so tight in fact that the play-out machine hadn't finished caching the audio as the second half of the edit started to go out and guess what - holes in the audio. They were "real holes" that is no audio at all, and they could be clearly heard on BBC2 as well as the HD Channel, no consolation I know but we had to put this down to machine failure and unlikely to be repeated.

Back to Strictly and a live OB from Blackpool, not the sort of show you want to mix from the back end of an OB truck no matter how big! Due to running around all day and several accidents in front of me on the M40, I didn't get to a TV in time for the start and then it was BBC One only. It didn't take long for me to find out there were serious audio level problems on the HD Channel but what was worrying was no one in the broadcast chain could hear it, to me that shouts metadata!

Later that evening I listened to the programme at home and it sounded like the set top box was being over driven. Strictly has a pretty tough mix and if the metadata isn't right it will cause major problems with the dynamic range control in the set top box. By Tuesday morning, I had the tape from the OB and could see the metadata and knew what settings the sound team thought they were mixing to and, more importantly, what they actually set.

It was quite amazing hearing the difference when I switched between the two metadata settings. We have now gone through the metadata requirements for the programme and made sure they are fully implemented.

What next? The Remembrance Day service is a very important event and due to the complexity of the OB it was going to be in stereo. When the programme started I just couldn't believe I was hearing production talkback and what turned out to be Radio 4's sound. Sending a non-broadcast audio circuit, or another networks audio to air is just wrong and should never happen. The seriousness of this incident meant an immediate investigation.

On the day the links had been established in good time and a problem with the incoming talkback circuit was identified. The stream coming back from the OB contains several audio channels and communications circuits embedded into the video signal. This is quite usual and guarantees the audio and video paths are the same and therefore always sync. The stream contained the main audio, clean audio (no commentary), Radio 4 audio and communications. To help fix the talkback problem the audio channels were "shuffled" so talkback appeared in place of the main programme along with Radio 4 - this should never be done. During the final line up phase the talkback was muted and the Radio 4 audio at that point would have sounded identical to the TV audio. In other words the channel director would have had no idea anything was wrong.

Last - and it better be! Yes, Doctor Who should have been in 5.1!

Something the dubbing mixer pointed out quite forcefully on the Monday morning after transmission. Before he contacted me I had discovered the programme was only in stereo on the server but the delivered tape had the full surround audio. After a bit of investigation we discovered someone had routed one of the server ingest video tape players to another area and changed the audio replay options to a non-standard mode. When the machine was routed back to its normal role the audio set-up was not reset and the next programme in the stack for loading was Doctor Who.

Machine or circuit failure is one thing that we all have to accept happens occasionally and we apologise if it does. But I have made it clear we must stick to agreed practice and procedures because they are there to prevent errors. I hope the action we have taken will keep the audio on the channel running smoothly with no more mistakes.

In my next post I want to talk about the Channel's HD coding in general as an opener to the main encoder testing posts.

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

Comments

  • Comment number 1.

    Thanks for posting Andy, looking forward to reading the rest of your reports. I really hope it answers some fundamental issues with regards to inconsistent picture quality as many non technical viewers and non geeks have noticed.
    I'm still surprised that simple independent viewer test hasn't taken place, 2 identicle tv's calibrated, with playback sample of various types of programmes e.g. sports, wildlife etc affected from a HD PVR with 16mb/s and 9.7mb/s.

  • Comment number 2.

    Thanks Andy. I'm cynical about this whole process though, it's only going to prove that the BBC line is correct and what we see in front of our eyes is wrong...

  • Comment number 3.

    Kudos for braving your critics, Andy, I fear you're in for a lot of negative comments and you must accept that the BBC has brought much of this on itself.

    As you say in your opening blog, there have been a lot of audio issues on some flagship programmes which might be excusable for a tinpot outfit operating out of a shed. But when it a corporation with the resources and experience of the BBC / Red Bee, it does seem bizarre.

    It's also problematic that nobody in the broadcast chain noticed some of these issues, instead relying on you sitting at home watching TV. Mistakes and failures happen, but it strikes me that the procedure for detecting these is sorely lacking.

    I know you're going to cover picture quality in a future blog, but I watched Gavin & Stacey last night (Sky HD, LG 42PQ6000) and was distinctly underwhelmed by the PQ. I've recorded the SD version and there's honestly not that much difference. Compared even to upscaled programmes on C4 and Sky1, the BBC doesn't come off well.

  • Comment number 4.

    @Andy

    Thanks for the great post. If the following posts are as candid and adopt a similar tone then I am looking forward learning a lot over the next week.

    Of particular interest would be info relating to any direct comparison A/B testing of the new encoder versus the old and exactly how the Objective and Subjective tests were performed and data interpreted. I know you've probably written this article already, but is it too late to ask that images are included for illustrative purposes?

    With regards audio (after all that's what this posting is about), my main comments would really be relating to a request for more programmes to go to 5.1 rather than stereo but I understand this is a decision that will be made earlier in production and is subject to budgetary constraints. 5.1 audio, for me at least, was quite a big incentive for me to 'go HD' and I suspect this is true of many others.

    Again, thanks for the blog.

    Thanks again.

  • Comment number 5.

    Interesting insight Andy. Thank you.


    We shouldn't forget we've living through the pioneering days of HDTV.

    I've seen telerecordings from the pioneering days of SDTV where _everything_ went wrong. Tapes wouldn't play. Film inserts would break. Microphones would fail. Cameras would give inexplicably horrible pictures.

    ...all before the broadcasting world used PC-like equipment, giving the opportunity to _really_ mess things up!


    ...and while we all suffer unpredictable digital technology in our homes, we expect that used by broadcasters to be perfect. Hopefully it'll get more reliable, and human error will intrude less, over the next year.

    Cheers,
    David.

  • Comment number 6.

    Just an initial 'thank you' post for this and the upcoming blog posts.

    I really hope that when you cover the BBC HD picture 'quality issues' you refer to the picture quality that is expected to arrive at our TV at home and not just about internal 'studio fed TVs' - because certainly what I see now is not what WAS the 'quality HD' of over six months ago.

    Looking forward then to your Monday post.

    Cheers, daveac

  • Comment number 7.

    Andy I would like to Thank You for taking the time the make a series of blog posts on various subjects of HDTV. Can you confirm who provided the Ob facilities for the rememberence service parade and also for Strictly from Blackpool ? I am surprised at nobody noticing the errors on strictly as they were operating with dual path uplinks from Intelsat and Atlantic bird if i remember correctly obviously something was wrong with the monitoring back in London and also by SIS in the HD uplink truck

  • Comment number 8.

    Andy, thanks for this part 1, looking forward to the rest.

  • Comment number 9.

    Dear all

    Thank you for the comments. I thought I would make one point a bit clearer re "no one in the broadcast chain could hear..." On several occasion including the now notorious Eurovision Song Contest 1.0, the audio in Television Centre, Red Bee and Siemens was perfect. The error occurs in the STB and a quick listen to off air may miss an intermittent error (the holes), or catch a section of audio that's OK (Strictly)..

    I hope you enjoy next weeks "episodes". They have been written openly and honestly and just deal with the facts as I find them.

    Andy

  • Comment number 10.

    Thanks for starting your feedback Andy, I will be glued to you for the next week (when not watching BBC HD). Probably a good idea to split up the feedback into different sections, however it will be your comments on the poor picture quality that will be most anticipated. One sound question, is the sound level lower on HD than other channels? It seems so via my V+ box. I always have to turn up the volume. Thanks for explaining what caused the Doctor Who 5.1 problem. It might be worth checking the machine playing Gavin and Stacey, someone might have left a VHS copy in there.

  • Comment number 11.

    I view BBC HD using a win 7 PC and media centre via XBOX360.

    The audio issues for me are key - get the mistakes fixed and I'll live with the picture quality.

    Far more annoying is the 20 second delay that now occurs when tuning to live or viewing recorded HD content from the new encoders. (Playback of recordings made with the old encoders is instant)

  • Comment number 12.

    Hi Andy,

    Many thanks for taking the time to post all this info.

    Is there a technical reason why you can't have a computer hooked up to the sound output from a STB and the sound output from the studio output and compare the two?

    If sound on the STB is silent for > 100ms and there is sound on studio output, then flag the problem.

    Regards,

    Gary.

  • Comment number 13.

    Thanks for the info Andy,

    I'd like to say that not everyone thinks you are involved in a great HD conspiracy, I've found your posts to be both honest and open.

    I do think there is a picture quality issue but I think it pre-dates the new encoder. I'm looking forward to your post on that.

    Keeping things on topic though, would let us know what the fixes for the sound issues are (when found)?

    The reason I ask is because Sky suffer the same problems on their channels (SD and HD) with some content. The opening credits (1st 3 minutes) of The usual suspects always suffers a problem for example).

    Due to their arrogance, they won't look into the problem even though I have recreated it at their technical support department. I hoping they'll read this and get some tips on

    a) Fixing the problem
    b) How to Provide a good service to their customers

    Cheers,

    Andy.

  • Comment number 14.

    Dear Andy,

    I look forward to your travails with interest. It's easy to forget the complexities of the new sometimes.

    I think we all appreciate your engagement on something in which we all have an interest or stake.

    'S'.

  • Comment number 15.

    Thank you Andy for the detailed and candid explanation of the sound issues that have occurred over the recent months on BBC HD and the steps taken to prevent recurrence. It's reassuring to know that you personally have been hearing the same sound problems heard by the many posters on the HD blogs (i.e. we are not imagining them). I expect you can see where I am going with this. I notice there isn't a general topic on picture issues planned. Can we therefore expect to see somewhere within the next 5 topics, a similarly candid confirmation that you have also personally seen the much more frequently reported HD picture quality issues?. If not, that silence will tell a story of its own and may well overshadow what you do say.

  • Comment number 16.

    Dear Gary Sargent
    Thanks for the comment. Unfortunately the holes in the audio were around 10ms long and the although "not nice" to listen to the Strictly audio was perfectly legal! I want to look at methods of comparing pre and post encoded audio.

    Dear Buzzy, I am glad you can decode the new stream, there have been problems with some hardware/software versions. Do you look at
    http://thegreenbutton.com/forums/t/73544.aspx?PageIndex=8 - they may have a solution.

    Dear vism, I will listen to the audio on Usual Suspects. As the SD audio is usually taken from different audio tracks, if there is a problem it may well be the programme as delivered. I would be surprised though

    Andy

  • Comment number 17.

    Hi Andy,

    Usual suspects showing Wed 23:55 on Indie/Indie HD.

    Opening sequence as the camera pans across the water.

    First prob happens while title says "brian singers film", there are some more over the next few seconds and some throughout the film.

    Both SD and HD are in dolby digital, I have turned DD off on the box (to record the stereo stream) and had the same probs but I'm not sure the HD boxes record the stereo stream or just multiplex the DD

  • Comment number 18.

    Andy,

    The audio problems are just about bearable. What's not bearable is the picture quality. You must watch BBC HD at home sometimes (or is it too much of a busmans holiday?). The "it's all new technology/still experimenting" crap just doesn't wash anymore. Sky viewers have 35 HD channels to choose from and BBC HD is the only one we are having problems with. As I've said previously, if you ever watch a programme called Cold Case on Sky One, it's the softest picture of anything I watch but it's still a million times better than anything on BBC HD.

    You claim you will attempt to answer us honestly, can you honestly say that when you're on your sofa at night with your feet up you can't see what we're seeing?

  • Comment number 19.

    Sky are a long way from perfect.

    The movie channels can be quite variable and suffer similar probs to the BBC HD channel (see my "Something interesting about Anytime at the moment" post on digitalspy) but let's stay away from picture for now, this blog's about the audio.

  • Comment number 20.

    I'm new to BBC HD, having only had it installed since the new encoders. I'm not trying to be a nag, but BBC HD can't even do a fade to black properly without it doing so in 5/6 increments. Likewise with the DOG - the dog is nice, its plain - but if anything moves under it, it breaks apart and looks worse than a 1990s web video. I can understand why people are angry when they are told to their faces that there is no problem - it isn't especially bad, it's still definately a HD service. But there is still a problem, unless a memo was sent to all programme producers to not use the space where the dog is or use fades.

  • Comment number 21.

    Thanks for the post Andy. Much appreciated and I genuinely mean that .

    Looking forward to seeing a post about picture quality but i have a sneeky suspicion the usual fob off is coming our way next friday "Friday: Programme styles and closing thoughts" lol. Please dont let your hard work end with the fob off that the difference in pictures we are seeing are simply programme styles.

    We can all see the quality is awful Andy. The channel is starved on bandwith and we can all see that. People have shown proof.

    What would be good as well would be to hear why BBC HD uses a fixed bit rate on sky and why they do not broadcast in a higher resolution.

    Also would be good to hear why you cant just admit theres been a reduction in quality and that the bandwith allocated cannott cope.

  • Comment number 22.

    Thankyou for the post Andy. I have done a little Dolby encoding and do appreciate how complex Dolby can be. Dropouts are very annoying and it is amazing how sensitive the ear is to them. The main problem I see from the BBC is that surround sound is used so little. Most programs still seem to be in stereo so please can we have more surround sound. There is a noticable difference in sound level when switching between 5.1 and stereo and so if more programs are made with 5.1 will reduce the problem.

    There is another issue with respect to audio which I am rather reluctant to raise. With Blu-ray discs we are now oftem treated to 7.1 surround sound LPCM 24bit with 96khz sampling which sounds realy great. So what I am saying here is that 384kb/s dolby is begining to sound a bit dull. Is there any way to improve the sound quality. I read in one forum that Freeview HD was using AAC encoding for the stereo sound. I suspect they may have got it wrong. I also understand that Freeview HD has droped the audio bit rates to 320 and 128 kb/s for 5.1 and stereo respectivly. Is this true?.

    Although these blogs are interesting they will be useless unless they tackle 2 issues.

    1) The BBC must acknowlege that the picture quality on BBC HD is unacceptable. This does imply that research needs to be done to establish a minimum picture quality which would be acceptable to say 90% of viewers.

    2) The BBC must have a plan to comply with that picture quality.

    The biggest failure of Ofcom was not to establish minimum quality standards on digial tv and radio. Ofcom pursude "choice" at the expense of quality and so we now have the choice of a large number of low quality TV and Radio stations. In the good old days of analogue television picture quality was assured in the signal specification. Such things as video circuit rise times and signal to noise ratios were strictly controlled. Infact analogue television produces much better overal picture quality than many digital channels.

  • Comment number 23.

    Good evening for starters. Secondly, Andy - thank you for what will no doubt show to be a great deal of time and effort spent in responding to the discussion about various aspects of BBCHD that have come forth over the past months and for that I truly believe that both yourself, and the BBC as an institution, should be applauded.

    There are both sound and PQ issues that currently affect BBCHD of which we are all aware but I thought it prudent of me as someone who has moved more to the critical angle of the channel of late to put a few things in the mind of those who seem, generally outside of these forums, to want to hit Auntie Beeb with anything they can.

    I personally have had a pretty awful week all told, but this evening on the way home from our fair capital and this evening, through the wonder of the iPlayer have enjoyed about two hours' worth of some wonderful intelligent comedy from The Thick of It. It has lifted my mood a stunning amount and I thank all and sundry for it.

    The comparison I would make is that my mood now is how I see BBCHD - low, fuzzy, unclear and not very vivid. The BBC is capable and has proven itself both in terms of program and radio quality to be the best in the World as it has technically.

    I wholeheartedly accept Andy's comments in respect of the sound issues. Things like the DW 5.1 fiasco happen - we're human, things go wrong (hence I suppose the irony on the program it happened on). Audio is a complex issue.

    So is PQ. And I sincerely hope that the same honesty about sound comes through with PQ. Not wanting to stray off topic, but Andy you have outlined the differences between broadcast and receipt in respect of sound - could the same be true in picture and if so, surely you're seeing the same as the rest of us? Here's hoping.

    Just one final thought. A few years ago, the BBC One announcer told us that the BBC had its own Christmas present for us in the shape of the first Christmas Dr Who. This year we're promised an absolute treat.

    Please Auntie - don't break it. Make it all work as it should and make Sky look once more at the BBC as to how things should be done as opposed to the other way round. That'll do for me for Christmas.

  • Comment number 24.

    "After a bit of investigation we discovered someone had routed one of the server ingest video tape players to another area and changed the audio replay options to a non-standard mode.."

    That is SO "IT Crowd"... I love it...

  • Comment number 25.


    I did notice audio being out of synch on the Tennis . It did not even register on
    my Annoyance scale of 0-10 because I recognised it as a technical glitch which would be put right at source and so it was. I expect a few teething troubles with a new system and make allowances for it.
    I'm using a Panasonic SC-PT860 5.1 Audio system. It was not expensive and I didn't expect much from it but was very pleasently surprised.
    The 5.1 adds another dimension to the enjoyment of a program and I should like
    more programs to have it if possible.

    One Audio related issue is the HD adverts , (the shark, etc ) they are much louder than the programs either side- is it the transmision or my kit? I'm not technical so I have no way of knowing. But it only occurs on the HD channel when routed through the SC-PT860. and it's that loud I have to turn it down , making the next program too quiet so Then I turn it up again only to get caught by the next advert.
    Overall i'm pleased with the audio, looking forward to the post on monday.

  • Comment number 26.

    Andy, thank you for finally providing us with your long-awaited Blog and, of course, I've no qualms about you quoting my name in it. I think that the serialisation is a very good idea, by allowing people to comment on specific topics the BBC HD team will be able to see at a glance which of them is of most concern to its viewers (I'm suspecting that next Thursday's will provoke most comment, but we'll see).

    I'm pleased too to note that, thus far, you've been candid and devoid of (The Thick of It, and dare I say POV, style) spin in your Blog. I know that you've already written the other installments but my hope is that they will continue this trend. I'm also hoping that your closing thoughts will be able to placate those of us who have seen, with our own eyes, a deterioration in picture quality on the channel recently, giving us a vision for the future of HD television from the Corporation and, perhaps, some confidence that significant improvements are in the offing in the nearer term.

    Moving onto the first topic of sound, I personally seem to have missed all of the programmes where you have highlighted that there have been sound issues. Never-the-less, I note that there have been quite a few problems and appreciate that you are doing your best to eliminate such human errors from the delivery of the channel's audio element.

    Actually, the sound is a very important aspect of the overall HD experience to me; as a latecomer to HD television, my viewing equipment is a bolt-on to an already existing high-quality audio set-up. For this reason, I have been disappointed during the last year by how few programmes seem to be transmitted in DD 5.1. It's particularly frustrating to turn on a long-awaited serialisation to find that it's just being transmitted in stereo (Top Gear, Little Dorrit, etc.).

    I do note the complexities involved in the delivery of 5.1 to which your Blog alludes, particularly for live programming, and I'm sure that the added cost is a limiting factor, however, I urge you and the enitire team to try to make 5.1 the channel's norm and not the exception. I agree with John's post above, that the adverts come out very loud in comparison to the programmes. I think this is particularly pronounced when the before/after offerings are just in stereo, so the ideal solution for me would be to have the audio quality of everything on the channel matching the power and impact of these inserts.

    Enough said, the Barbarians match is just coming on sadly only on BBC 1 - although that's a topic for another day! Best Regards, Paul.

  • Comment number 27.

    The main issue I have with these blogs Andy is doing is that the main issue we are all unhappy with is Picture Quality. I dont really care about the history of HD to be honest and the fobs offs that will be coming with that.

    All I want is Andy to Admit the quality just is not good enough and to tell us they are going to sort it. Sadly that doesnt look like its coming.

    Just be HONEST (wow big word for BBC HD) and admit theres an issue. Admit the bandwith is not good enough but be brave enough to admit BBC HD dont care if thats the truth.

    The issue must be resolved and fast because people look at BBD HD and its staff and laugh. Thats not having a go but a fact. To quote a member of staff at a local electrical store, "BBC HD must have junior school children running the channel".

    Its nice to have nice big blogs to try and divert us from the big issue, but sooner or later someone is going to have to accept some responsibility and face up to some home truths.

    If no one at BBC HD cares, then can I ask why they work there??

  • Comment number 28.

    Can I also just ask Andy what he feels about all the upscales currently been shown??

    Do you not feel everything should be in HD???

  • Comment number 29.

    Andy states

    "The BBC HD channel is two this weekend and in that short time we have developed one of the widest ranges of programmes you could find anywhere in a single HD package "

    BBC HD does not broadcast a wide range of programmes. It transmits very few films and almost zero sport. In any case Sky 1 HD has a wider range programmes. Sky has 35 HD channels each related to a different gendre of programme. BBC HD is a very small player in the UK HD scene with just 9 hours of programmes each day many of which are repeats.

  • Comment number 30.

    Straying off-topic for a second, #29, Trevor - of course I'm in complete agreement with you on all of that. There is not nearly enough Sport or film and, quite honestly, the Barbarians match I just enjoyed should have been on BBC HD, despite its problems, because the PQ on BBC 1 was an absolute disgrace.

    How the BBC can expend so much licence payer money on delivering the content whilst expecting the viewing public to put up with that sort of final picture quality is beyond me. I can honestly say that I was more satisfied back in 1973, for that memorable match on the last occasion the Barbarians won, with the analogue picture on our then newly rented colour TV.

  • Comment number 31.

    Can we try and stay on topic please.

  • Comment number 32.

    It is still beyond me why BBC cannot simply tranmit HD at a higher bit rate and resolution. Is this blog going to answer this simple question?

    HD is all about the highest quality. It has no reason to exist if it doesnt provide that. I can watch the programme already in reasonably SD quality.

    Honestly, as I have a full Sky HD subscription, I watch virtually no BBC output other than that on BBC HD - apart from the news.

    Please, if you are going to force me to pay my licence fee just to watch one channel, at least have the decency to broadcast it in the highest quality that anything labled HD deserves.

    Other broadcasters can do it, and do it right. Come on BBC get it right too.

  • Comment number 33.

    Many thanks Andy for your 'Opening' blog on the various issues affecting BBC HD, and thanks also for, finally, acknowledging the problems during Strictly Come Dancing from Blackpool.

    Sadly, tonight, we also have vision issues affecting Strictly in the form of repeated horizontal green, (and other colours), lines across the screen.

    What caused this?

  • Comment number 34.

    #post 33 jtemplar wrote:-

    'Sadly, tonight, we also have vision issues affecting Strictly in the form of repeated horizontal green, (and other colours), lines across the screen.

    What caused this?'

    Yes I had those lines - I'd thought it was a Taxi or some car passing causing interference!

    I will say that earlier tonight Doctor Who 'Dreamland' looked good - although I've read in a few forums tha a 'cartoon' or 'animation' is less demanding of bit-rate - still it did look good so thank you for that.

    Cheers, daveac

  • Comment number 35.

    Gavin and Stacey tonight, total loss of sound for at least 5 minutes, gave up and switched over after a while. Lets face it you don't watch that program for the picture quality! Sorry Andy sounds problems continue. (BBC HD via Virgin)

  • Comment number 36.

    Just want to thank Andy and the rest of the tech team for giving us many upscales again today, what I dont understand tho is you are giving us lots of upscales recently yet there is no Simulcast channel, why is this??

  • Comment number 37.

    Why can't people concentrate on sound issues with this blog?

    Is it really so difficult to wait a few days until the picture blog is published?

  • Comment number 38.

    #37, @vism fair point, but in defence of myself and others the overalll heading for the Blog is: "The Hitchhiker's Guide to Encoding: Before we start" and this first installment is entitled: "Opening and audio issues", so I think it fair that people address both the opening comments and ethos of the Blog, as well as audio issues, on this first one.

    In defence of my own meander at #30, which Nick objected to, I have to say firstly that I was hopping mad, after the match yesterday, that my enjoyment had been spoiled by vast quantities of the sort of PQ defects that are currently spoiling our HD viewing. Then I wanted to make the point, while it was fresh in my mind, in a Blog that I knew Andy would be likely to be reading.

    On reflection though, and why I raise it again now, I don't actually believe it is off-topic nor unrelated to the Audio issues that Andy has described. He has made it clear, in the section of this Blog, entitled "The Holes at the End of the Chain", that several Audio problems have got through the safety nets because they are at our end of the chain, i.e. the STB.

    He even reiterated it himself when he added a comment to say: "On several occasions including the now notorious Eurovision Song Contest 1.0, the audio in Television Centre, Red Bee and Siemens was perfect. The error occurs in the STB and a quick listen to off air may miss an intermittent error (the holes), or catch a section of audio that's OK (Strictly).. "

    Now, I relate this exact scenario to yesterday's rugby match. I'm certain that the TV Director, perhaps sitting in an OB truck at Twickenham with a top-notch monitor, almost directly connected to the cameras, thought that his/her picture was perfect. Perhaps elsewhere within the BBC, other Executives, watching on equally high quality equipment and connectivity felt the same.

    Meanwhile, back at home, the viewer, just like those experiencing audio holes in other programmes, is watching what is coming out of the STB with steam coming out of their ears because the pictures at that end of the chain are ruined by macro-blocking, posterisation, etc. to the extent that he/she can't read the numbers on the players' shirts, see the players' faces, nor sometimes even the ball.

    Like the audio issues, shouldn't the BBC be accountable for these problems too? Or, are we to expect that so long as the transmission leaves the OB truck in my example picture perfect, or in Andy's example leaves Television Centre, Red Bee or Siemens audio-hole free, then the BBC has done its job? Personally, I think not and I would hope that Andy agrees. I hope too that Nick and vism accepts my explanation for straying a little.

  • Comment number 39.

    Sorry to stray a little but just want to say that contrary to ealier posts at #33 and 34, I saw no horizontal lines during SCD. In fact I thought the PQ was quite good, much more like I expected when I decided to go to Freesat and which has been so sadly lacking on previous programmes.

  • Comment number 40.

    I, like others, am more concerned with PQ issues, but just to confirm that I agree that there were horizontal lines during SCD, but only momentary. Also, to stay on topic, a couple of short audio "holes" and some white noise issues, which nobody here has mentioned, but noted on another thread. Just as clarification, my audio is straight from the TV stereo speakers, and not through any external 5.1 setup.

    Although it's good to have Andy's long awaited comments, everything points towards "there's no problem, it's all in your imagination, we're not changing anything, you're all geeks" as the outcome of the PQ. Why not deal with the most important and controversial issue first?

  • Comment number 41.

    Well I too also saw the horizontal lines on SCD, they were to be clearly seen and looked like a transmission fault to me.
    I have also just seen the second Gavin & Stacey on BBCHD.
    Hullo Andy, no way was that 'stunning' HD. One wonders whether any of the high-ups actually sit at home and watch this stuff. If they did, they would see what we are all seeing, below par HD.

  • Comment number 42.

    Yes, I saw them too. Recorded by my Humax PVR. There was a burst
    at the end of the continuity announcement before the show, and about three or four more instances during the first 30 mins or so. Looked to me like a problem with the HD-SDI stream, and not anything at MPEG coding level.

  • Comment number 43.

    Stop imagining things.

  • Comment number 44.

    Re: Danielle's POV HD PQ Response, #517 @rmgalley. If you're reading this one, don't be put off from registering your comment over on Danielle's Blog. These HD PQ Blogs get so busy that when they reach 500 comments they slide over to a new page. To reach it you have to find the tiny "Next" button just underneath post 500, LHS. Press it and you'll find your comment, along with the other 16 on the new page. Be quick though, Nick will be closing it soon.

  • Comment number 45.

    I wasn't watching SCD but also saw lines as mentioned above and a very short sound drop out during "the thick of it" later in the evening.

    I also caught the end of "Mitchell and Webb" Last evening...Im sorry Danielle & Andy but no way was that HD.

  • Comment number 46.

    Re 34 & 41 - Green and Grey horizontal lines across the screen on 'Life' just now.

  • Comment number 47.

    A strange problem for Andy to consider, I've seen (heard) occasional strange problems on the BBC HD audio for some time. The dolby audio goes all chipmunk for the whole duration of certain programmes, squeaky voices, motor boating noises in the background. I don't have standard freesat gear so haven't made a proper complaint but this seems like the right place to mention it, perhaps odd corner cases like this can help uncover other problems.

    I'm playing recordings of BBC HD on a PlayStation 3, (transport files) the recordings are made with MythTV a software PVR system. That said it's a consistent problem that keeps re-appearing. I first heard it on the final episode of Torchwood Children of Earth, all other episodes were fine. When I recorded the re-run, same problem, only on the final episode, I've since had it on Montezuma (went to watch it as Andy said the PQ was so good) and all episodes of Last Chance to See. Nothing lately but I've had this both pre and post new encoders. Oh and the recordings play fine until the dolby switch at the start of the programme and normality is resumed after the switch at the end of the programme, I checked. I have a surround sound amp and the effect is the same whether the PS3 decodes the dolby or the amp does, was hoping that would be a fix.

    If I make a bluray of these recordings (remux not re-encode) then all is fine again, in fact this is the only way I was able to watch Last Chance to See.

    Of course the problem is almost certainly Sony's fault although it has persisted through many many firmware updates where lots of other issues have been fixed. Perhaps Andy can find out if there is something in common between these shows, maybe some ingest setting like the recent Doctor Who problem?

  • Comment number 48.

    AndyQ: Many thanks for the first if many.

    1. Please try to increase the use of 5.1 DD sound, it does make a difference
    2. Will you be explaining your use of the term "unsustainable" bit-rate?
    3. Please consider a new blog where your team lists the problems they have detected and are investigation. I accept there will be problems and I am very happy to wait for your team to fix them; what dismays me is when the BBC HD seems to be saying "what problem".

  • Comment number 49.

    I'm only able to receive BBC and ITV HD. ITV HD is next to useless as a service. However, I'd love to know if Sky have similar problems with the transmission of their HD output ? How is their 5.1 sound, lip-sync, and picture quality generally ?

  • Comment number 50.

    Knock Knock is there anyone there!!!!!

    Green lines on Antiques Roadshow and Small Island tonight.

    Is anyone on duty tonight or have they all gone down the pub.

  • Comment number 51.

    The Hitchhiker's Guide to Encoding:

    http://img188.imageshack.us/img188/1323/bbchd1.jpg

    Encode that Slartibartfast!

  • Comment number 52.

    Just as we thought BBC HD couldn't get any worse with its lack of definition, blocking and sound problems the dreaded green lurgy strikes our screens. No doubt Danielle will tell us green horizontal lines are deliberate and they are a filmic effect. Well I hate to tell you this Danielle the lines have to be virtical to be filmic. May be the editor was so drunk that he was laying on his side when he added the effect.

  • Comment number 53.

    Green lines and sound dropouts on Top gear tonight.

    Didn't think the audio was very clear either (even for stereo/pro-logic), vocals drowned out by background noise such as the audience.

  • Comment number 54.

    Dear all - It looks like the flashes are coming from the continuity mixer circuits in playout, the engineers are testing each section at the moment and I will update as soon as I hear from them.

  • Comment number 55.

    It's a little concerning that most of the "problems" seem to happen at weekends - remember the SCD problems? The night of Dr. Who and the launch of TG? Now we have both picture and sound issues again over a weekend.

    I have to ask, does anyone at TVC pay attention to what gets transmitted, by looking at off-air rather than what is going out? Is it all within the remit of Red Bee to spot and report/rectify these problems when they happen? If it is, I hope Andy has been involved in a "full and frank exchange of views" with them this morning.

    Maybe it is time to bring presentation and playout back "in house"?

    @NickReynolds - Your "off topic" alarm is probably sounding, but I can't think where else to post - this is the most current...sorry :-)

  • Comment number 56.

    Dear RayB - your comment is fair here as this blog is an opener as well as audio. The "full and frank" is waiting for the outcome of the tests going on three floors below as I write. I have already asked for a contingency plan for this evenings programmes.

    Andy

  • Comment number 57.

    Andy, are you still transmitting stereo only on the dolby digital 2.0 transmissions or are you now multiplexing a surround channel to create an old style dolby surround transmission for decoding with pro-logic?

  • Comment number 58.

    Dear vism - we transmit 2.0. We only have one option on the HD Channels at the moment so we use the same format for stereo (2.0) and 5.1. Unfortunately some time the switching signal stays in 5.1 mode for 2.0 programmes. All that happens is your AV amp stays in 5.1 (or 3/2) mode but with audio only on front left and right.

    Andy

  • Comment number 59.

    Re: 56

    Thanks for your understanding, Andy.

    I'd love to be fly on the wall when the discussion takes place - to my mind there are too many errors especially during evenings and at weekends and it seems to be getting worse, not better. The BBC of old would not have tolerated the same faults on consecutive programmes, let alone days!

  • Comment number 60.

    Last update in this part of the blog about the flashing on the output. The extra ventilation has cooled the vision mixer substantially and we defiantly going to use it tonight (with the contingency plan in place!). Assuming all is OK we will be talking to the manufacturer to find out why it should overheat. I will continue to post about the mixer in the later episodes as required.

    Andy

  • Comment number 61.

    Many thanks Andy for your multiple responses and updates - this feels more like what a blog should be like, particularly in these times of rapid technological change, rather than the 'write and run' we so often see elsewhere.

  • Comment number 62.

    Why do I have a vision in my head of a £10 desk van pointed at an expensive piece of vision mixing kit? :-)

  • Comment number 63.

    I've actually had visions of a fan-heater pointing in the direction of the desk by someone who "felt a little chilly" on Saturday evening...

    Is this mixer new?

  • Comment number 64.

    Dear GarySargent - not quite £10! RayB fairly. It may be due to other equipment close by though but it should be able to cope if fitted as recommended

    Andy

  • Comment number 65.

    Good to get your feedback Andy very refreshing to know there is somebody from the BBC reading these Blogs apart from Nick.
    Please keep it up when you can.

  • Comment number 66.

    Dear RayB - it was a strange mixture of very cold blasts of air next to very warm extractors last time I was down there. The HD vision mixer bay is pretty full though!

    Andy

  • Comment number 67.

    Andy,

    Was the Top gear studio stuff recorded as stereo or 5.1 surround?
    It was transmitted as dolby 2.0 and I'm still wondering why Clarkson's voice was low (rare I know) compared to the audience noise.

    If it was recorded in 5.1, what defines how much centre channel is muxed into the stereo audio. Do you have gain controls for that?

  • Comment number 68.

    Dear vism - Top Gear is stereo

  • Comment number 69.

    Hi Andy,

    Don't forget The usual suspects tonight. I'm recording the HD and SD.

  • Comment number 70.

    Both suffered problems on my recordings

  • Comment number 71.

    Andy - Dr Who on Christmas Day was in Dolby Digital 5.0 instead of 5.1!

    Is this programme jinxed or what?!

    Can you sort it out for part two?

  • Comment number 72.

    (Thought I'd post this hear, previously posted in Danielle's last blog, in retrospect a more appropriate place for it)

    Re the sound drop outs that people were experiencing on Doctor Who.

    I watched this as a recording played back on a Humax Foxsat-HDR with sound through a Denon AVR-1910 amp. I didn't notice any sound drop outs at all. However the following day after runing the audyssey setup on the amp I noticed that if 'dynamic eq' was switched on I did get a sound drop out. This was in the scene where the master was being brought back to life and his wife through the potion in, just as the explosion was finishing the sound would cut out briefly before it cut to a shot of the doctor in the tardis. Don't know how all of you are listening but maybe this is something to go on as I keep hearing about sound drop outs but don't seem to experience them myself. Maybe I'm not watching the right programmes! Incidently my normal viewing\listening kit is a Sky+ HD box and Marantz SR6003 amp.

  • Comment number 73.

    Kept a note of the sound drop outs last night during the repeats and new episode of Doctor Who. Three during 'Planet of the Dead', two during 'Waters of Mars', two during 'End of Time' part 1 and one during 'End of Time' part 2. How long have these problems been ongoing now? I can't beleive the BBC haven't got on top of them yet. At least we had the correct audio this time, even if it was only DD5.0

  • Comment number 74.

    Just watched part1 of Doctor Who. Picture quality was good but Audio was DD5.0 as mentioned above ** but DD5.1 was flagged as The Master was resurrected and then returned to DD5.0 at the end of that scene and remained for the rest of the programme **. However, my sub was (marginally) active even when 5.0 was flagged!?

    I guess HBO must have a much larger budget as True Blood & Generation Kill sounded amazing on 4hd. No sign of drop-outs or flagging issues either. How can a struggling Channel4 get it right and the 'mighty' BBC can't??

    AndyQ, can you please explain to us why the channel continues to have so many issues with audio? I am genuinely interested so a response would be much appreciated.

    Thanks.

  • Comment number 75.

    Andy, since Nick has directed sound issues here, I wondered if I was the only one who experienced a 1 second (ish) audio drop-out on at least two occasions during tonight's Top Gear, and a similar number in the immediately following Wallander programme. Most, perhaps all, were accompanied with a resultant, following, lip-synch issue which, as described in my other report about the Xmas Day Dr Who sound here: http://www.bbc.co.uk/blogs/bbcinternet/2009/12/bbc_hd_christmas_schedule.html#P90350254, was resolved by flicking over the channel, then back. One drop-out, during the Nissan road test seemed to cause a blotchy, purple horizontal line to appear and stay on the screen immiediately after. This wasn't resolved by flicking the channels, and needed a complete reboot of the Freesat box to get rid of.

  • Comment number 76.

    Hi Paul, I watched Top Gear this evening and didn't spot any drop-outs. I didn't see/record Wallander (is it a new series or repeat of the first?) and no drop-outs on ep1 of Doctor Who for me. Yet to watch ep2.

  • Comment number 77.

    #76, it's Series 2; last night - Faceless Killers (89 minutes)

    1/3. Wallander investigates the brutal slaying of an elderly couple at an isolated farmhouse.

  • Comment number 78.

    Damn. I had assumed they were repeats - this is BBCHD after all. Hopefully it will be on Virgin Media HD iPlayer.

    Better mention something about audio otherwise this post will be removed. I was disappointed that Hustle was only in Stereo tonight. Great episode though!

  • Comment number 79.

    No sound drop-outs on ep2 of Doctor Who. Still flagged as DD5.0 but a nice surround mix - particularly the score-bleed. Good PQ and a great ending to David Tennant's tenure.

  • Comment number 80.

    Dear all - back again and stuck in the snow. So bad here had to get outside and know the snow off the dish! Re Doctor Who etc., almost all programmes are 5.0 - the .1 channel is really a cinema option for big bangs etc. and most domestic systems use the sub for LF not the LFE channel. As we have to limit dynamic range adding LFE is not usually a good idea! I will check if there it was 5.1 or 5.0

    No holes in the audio were spotted over the holiday and I watch a LOT of HD. stephenb #72 may be worth looking at.

  • Comment number 81.

    Hello Andy,

    Welcome back. I'm normally more concerned about picture rather than sound quality, but I see that is being well covered on another blog at the moment. So, can you just go over #80 again please? Are you saying that henceforth BBC HD will for the most part be broadcasting in 5.0 (that is, when it's not 2.0)? If so, is this a change of policy? And I'm struggling to understand what you mean by "most domestic systems use the sub for LF not the LFE channel". Surely you aren't saying they ignore the .1 information, are you?

    Thanks.

  • Comment number 82.

    Dear HD_fan428

    Thanks for the comment. The use of the LFE channel for television is hotly debated - can domestic systems do it justice etc etc. If you have a set of full bandwidth speakers (that is 5) then the LFE channel will be correctly reproduced, however many AV systems use the sub channel to augment the missing (and far less directional) LF from the other channels.

    Now at 00:14 I am not going to enter an audio reproduction debate I would enter when firing on all cylinders - audio people are very passionate about the subject and how to reproduce audio for TV. On one side we have those who want you to hear the full dynamic range of a programme/film/concert on the other, or should I say on both sides, we have the neighbours!

    Andy

  • Comment number 83.

    Hi Andy,

    I would have thought most people with a 5.1 setup will have a decent one, and those with satellite speakers will be in the minority.

    HD Programmes coming from the USA being broadcast on Sky all seem to be 5.1 not 5.0, in fact Dr Who is the first time I've ever noticed 5.0!

    Gary

  • Comment number 84.

    Dear GarySargent - thanks for the post and unfortunately looking round the stores most AV systems seem to come with rather small speakers!!

    I leave the choice of 5.1, 5.0, 4.0 and 2.0 to programme makers

    Andy

  • Comment number 85.

    #84 Andy, "I leave the choice of 5.1, 5.0, 4.0 and 2.0 to programme makers"

    that's a shame and somewhat surprising to me. Considering the very stringent standards the BBC enforce for programme makers regarding HD video content, I'd have thought there would be similar minimum standards for Audio for HD programmes. Particularly so with Archiving requirements and also the Blu-Ray Export Markets in mind, even if you are not so concerned over the broadcasts to UK Licence payers.

    Most people who've emailed me on the "other" issue, who've described their systems to me (and most do), have mentioned routing their audio through an AV Amp and 5.1 Speaker system - I certainly do myself. The Audio on US shows such as Madmen, for example, is superb.

  • Comment number 86.

    Dear Paul

    All the options are available on all formats and the choice of the number of active audio channels will always be a production choice - if you are thinking long term archive 5.1 is already on the way out to 7.1 and taken to extreme 22.2!

    Enjoy the skiing

    Andy

  • Comment number 87.

    Hi Andy,

    Did you get to look at the problem with The usual suspects?

    BBC HD audio has been fine of late so I guess you've cracked it.
    If you do talk to Sky at any point, please let them know the issues you've had and how they were fixed (or post them here and I will send them to Sky).

    Thx.

  • Comment number 88.

    I do talk to Sky about audio issues (Sky and the BBC are joint chairs of the European HD Forum's audio group). Sometimes these things come a go before we can track them - sometimes the hang around no matter what we do to cure them too!!!

    Andy

  • Comment number 89.

    # 84, Andy Quested, 'I leave the choice of 5.1, 5.0, 4.0 and 2.0 to programme makers.' #86, 'All the options are available on all formats and the choice of the number of active audio channels will always be a production choice.'

    This strongly implies that what the programme is recorded in is what will be broadcast. Yet I understand that Blu rays of HD programmes are sometimes issued in 5.1 where the broadcast is 2.0. Can you explain this apparent contradiction?

  • Comment number 90.

    At last DD5.1 on sporting event where BBC are the host broadcaster. Keep up the good work as the mix so far has beean excellent. Can we look forward to similar for the six nations et all?

  • Comment number 91.

    Dear HD_fan428. Thanks for the post. If a programme is re mastered for DVD/Blu Ray in 5.1 it may not be as the original programme makers intended or it may be "up-mixed".

    Dear stehenb - thanks for the post. I am waiting to here the final specs for the 6 Nations

    Andy

  • Comment number 92.

    Dear Andy, thanks for your quick reply. So, just to be crystal clear, are you saying that you broadcast the programme as it comes to you? You never downmix it? I've just got an eye on that 'may' in your answer.

    Thanks.

  • Comment number 93.

    This comment was removed because the moderators found it broke the house rules. Explain.

  • Comment number 94.

    The new series of Doctor Who was in 5.1 instead of the previous 5.0, and sounded pretty good to me. Good to see more and more content appearing in 5.1.

    Andy any chance of a fresh blog post sometime to give us an update on all things technical with BBC HD? Anything interesting about the Freeview HD stream would be good too.

  • Comment number 95.

    All this user's posts have been removed.Why?

 

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