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BBC HD: Olympics Opening Ceremony Surround Sound

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Andy Quested Andy Quested | 13:25 UK time, Tuesday, 12 August 2008

This is a really boring post - no clamour of phone calls at home, no daughter discussing the relevance of the Eurovision Song Contest for Saturday evening viewing in one ear and no chance of anything like reverse karaoke!

So why wasn't the opening of the Olympics on BBC HD television in surround sound?

We had been having problems with the Dolby E stream on the line back from Beijing.

You have to remember we are sending back many video, audio and data streams from the games for all the interactive outputs, so it is a very busy set of circuits - but all seemed well just before the opening.

During a final rehearsal about 20 minuets before transmission, Red Bee noticed that the surround sound kept "popping"; meanwhile in the Television Centre switching area, they heard one or two pops - but not at the same time as Red Bee.

The problem was looked into at both ends and at about ten minutes before transmission, there were only a couple of options left - as these required a reboot of a large chunk of the system, you would naturally ask a couple of questions:

  • 1. would it cure the problem? and
  • 2. how long would it take?

As the answers were "maybe" and "more than ten minutes", I think the next step was obvious.

bbc_hdtv_truck.jpgIn my last post about the Eurovision Song Contest, I said we were putting in failsafe systems so that we could at least keep the high definition pictures if we had to use the stereo audio. Well, as promised, the infrastructure is in and the "failsafe" worked. (Photo of BBC truck at Helsinki World Athletic Championship in 2006 from timo_sw on Flickr)

We tried a couple of times during the opening to go back to what looked like a stable surround signal, but along would come another "bump" and in the end it stayed stereo.

Overnight (Beijing time) the systems engineers worked backwards through the chain to find the cause and the report back was during a check of a rack of equipment it stopped - that's it so far.

The next programme went on air in surround and it's been there ever since.

We are still looking into the issue to see if it was equipment failure, a problem with the link back from Beijing or a problem with the incoming audio from the host. Maybe I'll write another full post later!

Just for information, the host broadcaster is distributing 4.0 audio to all broadcasters taking surround. The sections from tape, archive material and the studio are in stereo.

Andy Quested is Principal Technologist, BBC Future Media & Technology.

Comments

  • Comment number 1.

    Thanks for the information.

    I do not underestimate the complexities of achieving live 5.1 sound. Thanks to all involved. Please keep up the good work. When it works well 5.1 can add another dimension to the broadcast!

  • Comment number 2.

    Thanks for that entry, Andy.

    However, although there might be special reasons in this case, why on earth was Britain from Above on Sunday only broadcast in 2.0 sound? Was this streamed live from Beijing too? ;->

  • Comment number 3.

    Bill - thanks for the comment. Surround Sound is sent as data packages using Dolby E. It is very easy to damage the package as it passes through the various processes on route back to Television Centre. The stereo signal however has a lot of error protection and redundancy that means we can loose a lot of information before we actually loose the sound.

    Mike0001- I'm afraid to say Britain From Above was made in stereo by the production company and was transmitted as made.

  • Comment number 4.

    Is there any chance of sorting out or at least giving a valid reason why there are no subtitles on freesat HD. The box I just brought (Humax Foxsat) says it can handle them and for 'hard of hearing/deaf' people they are the difference in making the programme worth watching or not. Why is it taking so long to sort out and when will it be done please?

  • Comment number 5.

    Andy, thanks again. What a shame that BFA was not done in surround!

    On another note, We watched Maestro last night on BBC2. We would have enjoyed it so much on HD but that broadcast was much later, as the dreadful Bonekickers had taken the priority 9pm slot.

    I look forward to the day when all your channels have their own HD equivalents! How long am I likely to have to wait?

  • Comment number 6.

    We are switching 2.0/5.1 again with a solution that might work and I would appreciate feedback about how it's sounding on as many home AV systems as possible. There may still be an issues with systems that mute during a change, but I hope we have minimised this too. I will say now that even if it works well, we will not be able to use this work-round long term but we are working with Dolby for a more elegant solution.

  • Comment number 7.

    Andy, re. your request about the 2.0/5.1 switching. I am using a Cyrus AV master to decode the audio. About a month ago there was a half second sound drop-out when switching between 2.0 and 5.1. However, this is now seamless.
    I have to say the surround sound is absolutely magnificent. I do have one question though. The first proms broadcast was 5.1, although this Saturday's (the jazz prom) seemed to be in 4.0. Am I correct and is there any reason for this?

  • Comment number 8.

    Charles_n, we do leave the choice of surround format to the sound supervisors. They make the decision based on content and style of performance. Please keep feeding back though - the main thing for us is did the use of 4 channel distract because you expected 5 channels or because the balance was not right?

    Andy

  • Comment number 9.

    Feedback As Requested

    AV Equipment :
    Onkyo TX-SR875, 7.1 Monitor Audio speakers,Virgin Media set top box

    Andy

    Dolby 5.1 sounding sounding great here and HD picture quality fantastic.This is how it is really done any other broadcaster should sit up and take note how to do it properly.
    I had noticed that it was in the same format yesterday but cant remember any earlier.
    Was it sorted today or yesterday?
    I liked the gymnastics where a particular move was shown broken down through its elements.great insight on just how difficult these moves are.

  • Comment number 10.

    AV Equipment :
    Onkyo TX-SR875, 7.1 Monitor Audio speakers,Virgin Media set top box,Panasonic Bluray player,Everything connected by HQ HDMI leads.

    Has the on screen graphics/Idents been improved?.I noticed when BBC HD was a trial channel some of the graphics were poor yet they seem alot smoother around the edges in particular.

  • Comment number 11.

    Andy, re. the previous post about 4.0 rather than 5.1 for the proms last Saturday. I have to say that I didn't find the 4.0 signal particularly distracting as such. With classical music I guess the presentation of a stereo image at the front with two surrounds at the back works well. So no complaints, I was just interested in the reason for the choice.
    Where I have noticed a big difference is in music with smaller ensembles. For example, ignoring the rear speakers and concentrating on the aural presenation in front of me, the Coldplay at the BBC programme is startlingly better in 5.1 than the stereo presentation on terestrial. The stereo image definately seems to have a hole in the middle of the soundstage when compared to 5.1.

  • Comment number 12.

    What are the BBC's plans for closing cermony sound DD or DS?

  • Comment number 13.

    Well done: BBC, China

    Thanks

  • Comment number 14.

    Andy,

    Can you tell us what is happening currently with the 5.1 / 2.0 switching?

    Everything is being flagged as 5.1 again.

    Also are you aware of the lipsync problems on Silent Witness on Wednesday night?

    thanks

 

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