BBC HD: Olympics Opening Ceremony Surround Sound
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!
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.
In 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.