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INTRO Roger Bolton Studio |
In last week’s programme a viewer asked why programmes don’t always start and finish on time.
This is particularly annoying when videoing your favourite shows and you can end up like the
reader of a detective story who finds out that the last few pages have been torn out.
The broadcasters wouldn’t guarantee to be better timekeepers and suggested that setting
the video timer with an extra five minutes before and after the advertised transmission time
was the safest way of allowing for their sloppiness.
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Following this advice, many of you contacted us to point out that the favoured method of
recording television programmes, VideoPlus, whereby a number printed in the listings is entered
in to the video recorder instead of the programme time, doesn’t do this.
Some of you also wrote to advise viewers on the joys of PDC. At this point my eyes
glaze over. P-D-what?
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Piece to Camera |
P – D – C. Three magical, mysterious letters appearing on video recorders everywhere.
They stand for Programme Delivery Control, which is jargon for an amazing invention that
allows you to set your video to record a programme, knowing that, even if the programme doesn’t run on time, you’ll still get the whole thing on tape. |
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Voiceover |
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But it seems to be one of broadcasting’s best-kept secrets, and I wanted to find out more,
so I started my own web site up about it. As it’s been visited over 7 000 times so far,
I guess other people are interested too.
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Andrew |
But what exactly is PDC? And how does it work? |
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Andrew as Einstein |
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Now this is the technical bit, so pay attention and listen carefully…
Every programme has a PIL, a Programme Ident Label, and that consists of the date, the channel and the time.
Now, just before the programme begins, the broadcaster broadcasts the PDC code, which contains the PIL, which causes the video recorder to begin recording.
Because the video recorder uses the signal and not the clock to decide when to start, it’s completely accurate.
Well we’ve spoken about starts, what about stopping? Some broadcasters transmit a stop code: some broadcasters don’t. (Some video recorders work: some don’t…)
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INTERVIEW |
So how reliable is PDC? |
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Richard Eagle |
Richard Eagle
Manager Technical Operations, C4
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It is in fact fairly reliable. There are the occasional failures, which are very irritating to the viewer who really wanted to record that particular programme. The problems tend to come with schedule complexities and especially late changes. But we can accommodate these in our control room by use of a special button, which reverts the system to TIMER mode and allows most of the programme to be recorded under normal circumstances.
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Andrew |
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At the moment, Channel 4 and Channel 5 have a full PDC system. But many of the ITV companies don’t.
BBC2 has an experimental system. But BBC1 has nothing. |
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Until this week, that is, when they suddenly announced some good news… |
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"There is currently an experimental service
operating on BBC2 and an experimental
service is planned to start early next month
on BBC1, with a full service following
shortly after." |
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So PDC is coming to a TV station near you, even if it’s not there yet. But will this new technology make it harder to program your video? Well apparently not, because most work with VideoPlus, so it should be just as simple. |
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INTERVIEW Hugh Peltor |
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Hugh Peltor CBE
Director, THE BRITISH RADIO & ELECTRONIC
EQUIPMENT MANUFACTURERS’ ASSOC.
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My advice to anyone going out to buy a video cassette recorder tomorrow is to make sure that it has two features: VideoPlus and Programme Delivery Control. That way you have the best of both worlds.
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Andrew |
On my web site I’ve heard from people who’ve had problems with PDC videos. |
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Hugh Peltor |
Yes, I think there have, particularly with the early models and in the early years of Channel 4, being the only broadcaster using programme delivery control. But clearly we’ve taken a lot of effort, by we I mean the manufacturers and the broadcasters, to iron out these problems. |
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Andrew |
Unfortunately there’s one problem that all the technology in the world won’t solve. If you want to record two consecutive programmes on two different channels, you still won’t get both programmes in full if they overlap because they didn’t begin and end on time. |
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Roger Bolton |
Which is all viewers wanted in the first place. |
