What controls the time a program starts?

By which I mean this. Last night I decided to use the lazy persons way of
operating the box. I scanned the prog guide and set reminders for all the
things I wanted to watch.
although it more or less works, I find that in some cases the reminders
tell me ahead of time, while the other show is running on aniother channel,
even though its supposed to end, in others the front gets cut a bit due to
the late reminder. I, being naive just wondered what controls the
switching, is it the actual time a show is started, or just the preset guide
even if this is slightly incorrect due to running issues or whatever.
Brian

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From the Sofa of Brian Gaff Reply address is active

Brian Gaff wrote:
By which I mean this. Last night I decided to use the lazy persons
way of operating the box. I scanned the prog guide and set reminders
for all the things I wanted to watch.
although it more or less works, I find that in some cases the
reminders tell me ahead of time, while the other show is running on
aniother channel, even though its supposed to end, in others the
front gets cut a bit due to the late reminder. I, being naive just
wondered what controls the switching, is it the actual time a show is
started, or just the preset guide even if this is slightly incorrect
due to running issues or whatever. Brian

It used to be a thing called Programme Delivery Control, or PDC, which
consists of signals sent by the broadcaster as hidden codes in the
teletext service, indicating when transmission of a programme starts and
finishes. I'm sure it will be the same sort of thing now, though how it
works exactly I'm not sure.

Norman Wells wrote:

Brian Gaff wrote:

just
wondered what controls the switching, is it the actual time a show is
started, or just the preset guide

It used to be a thing called Programme Delivery Control, or PDC

Now it's called 'Accurate Recording' but not all Freeview+ branded
recorder use it, let alone generic DVB-T recorders.

On 21/08/2012 08:28, Brian Gaff wrote:
By which I mean this. Last night I decided to use the lazy persons way of
operating the box. I scanned the prog guide and set reminders for all the
things I wanted to watch.
although it more or less works, I find that in some cases the reminders
tell me ahead of time, while the other show is running on aniother channel,
even though its supposed to end, in others the front gets cut a bit due to
the late reminder. I, being naive just wondered what controls the
switching, is it the actual time a show is started, or just the preset guide
even if this is slightly incorrect due to running issues or whatever.
Brian


Some of the problem may be due to delays in the way the PVR reacts to
the OTA signals. I believe that my Humax 9200T can take several seconds
(maybe up to 20?) before it starts recording.

Which raises the point of when do the signals actually get sent? When
the programme starts (as viewed live) or a few seconds before it appears
live? And what about turning off at the end? It seems unnecessary, and
very annoying, to miss a programme recording because the end signal for
a programme which finishes at 2100 are delayed until 2101 while adverts
or announcements take place, so overlapping with the start signals on
another channel where they are sent accurately at 2100.

--

Jeff

In article ,
Andy Burns wrote:

Norman Wells wrote:

Brian Gaff wrote:

just
wondered what controls the switching, is it the actual time a show is
started, or just the preset guide

It used to be a thing called Programme Delivery Control, or PDC

Now it's called 'Accurate Recording' but not all Freeview+ branded
recorder use it, let alone generic DVB-T recorders.

It depends on your PVR. For example, I have three Humax PVRs. The
HDR-FOX-T2 reliably starts up during the run-in announcement. The older
PVR-9200-T picks up the start cue but is slower to operate and clips the
first few seconds of the programme. The much older PVR-8000-T which was
their first PVR) doesn't have this facility and so starts and stops at
the exact times given in the EPG - usually clipping one or other end in
the process. As there is no auto-padding you have to go into the
recording list an manually add padding on each end to be safe.

Jeff Layman wrote:

Which raises the point of when do the signals actually get sent? When
the programme starts (as viewed live) or a few seconds before it appears
live? And what about turning off at the end? It seems unnecessary, and
very annoying, to miss a programme recording because the end signal for
a programme which finishes at 2100 are delayed until 2101 while adverts
or announcements take place, so overlapping with the start signals on
another channel where they are sent accurately at 2100.

Because of the way 'accurate recording' is implemented, there is always
exactly one programme running on a channel; as one starts the previous one
stops.

BBC are very accurate with their signalling, the running status changes at
the beginning of the station ident immediately before the programme. ITV and
C4/5 rather less so, and the Freeview channels seem to rely on clock time.
--
Dave

On Tue, 21 Aug 2012 11:45:23 +0100, Dave wrote:

Jeff Layman wrote:

Which raises the point of when do the signals actually get sent? When
the programme starts (as viewed live) or a few seconds before it appears
live? And what about turning off at the end? It seems unnecessary, and
very annoying, to miss a programme recording because the end signal for
a programme which finishes at 2100 are delayed until 2101 while adverts
or announcements take place, so overlapping with the start signals on
another channel where they are sent accurately at 2100.

Because of the way 'accurate recording' is implemented, there is always
exactly one programme running on a channel; as one starts the previous one
stops.

BBC are very accurate with their signalling, the running status changes at
the beginning of the station ident immediately before the programme. ITV and
C4/5 rather less so, and the Freeview channels seem to rely on clock time.

I find C5 start/stop very unreliable. I have stopped recording
anything on C5.

Steve

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EasyNN-plus. Neural Networks plus. http://www.easynn.com
SwingNN. Forecast with Neural Networks. http://www.swingnn.com
JustNN. Just Neural Networks. http://www.justnn.com

On 21/08/2012 11:45, Dave wrote:
Jeff Layman wrote:

Which raises the point of when do the signals actually get sent? When
the programme starts (as viewed live) or a few seconds before it appears
live? And what about turning off at the end? It seems unnecessary, and
very annoying, to miss a programme recording because the end signal for
a programme which finishes at 2100 are delayed until 2101 while adverts
or announcements take place, so overlapping with the start signals on
another channel where they are sent accurately at 2100.

Because of the way 'accurate recording' is implemented, there is always
exactly one programme running on a channel; as one starts the previous one
stops.

BBC are very accurate with their signalling, the running status changes at
the beginning of the station ident immediately before the programme. ITV and
C4/5 rather less so, and the Freeview channels seem to rely on clock time.

The BBC seem to spend more and more time on announcements shown between
programmes about forthcoming programmes (interminably so with the recent
Olympics), so if they signal just before a programme starts, then almost
invariably there will be maybe a minute or more of dross at the end of a
programme showing these announcements. That would perhaps not be a
problem if the other channels' programmes were late, but if they are on
time and the BBC "off" signal does not appear until their now late
programme (because of the announcements) is due to start - just after
the start signal according to your post - then that could mean missing
recording of the other channel's programme.

But why should the BBC care about that?

--

Jeff

On Tue, 21 Aug 2012 11:45:23 +0100, Dave wrote:

Jeff Layman wrote:

Which raises the point of when do the signals actually get sent? When
the programme starts (as viewed live) or a few seconds before it appears
live? And what about turning off at the end? It seems unnecessary, and
very annoying, to miss a programme recording because the end signal for
a programme which finishes at 2100 are delayed until 2101 while adverts
or announcements take place, so overlapping with the start signals on
another channel where they are sent accurately at 2100.

Because of the way 'accurate recording' is implemented, there is always
exactly one programme running on a channel; as one starts the previous one
stops.

BBC are very accurate with their signalling, the running status changes at
the beginning of the station ident immediately before the programme. ITV and
C4/5 rather less so, and the Freeview channels seem to rely on clock time.

I find my PVR (Humax PVR9300T) often misses the beginning of
programmes on the BBC, but other channels are worse.
--
(\__/) M.
(='.'=) If a man stands in a forest and no woman is around
(")_(") is he still wrong?

"Dave" wrote in message
...
Jeff Layman wrote:

Which raises the point of when do the signals actually get sent? When
the programme starts (as viewed live) or a few seconds before it appears
live? And what about turning off at the end? It seems unnecessary, and
very annoying, to miss a programme recording because the end signal for
a programme which finishes at 2100 are delayed until 2101 while adverts
or announcements take place, so overlapping with the start signals on
another channel where they are sent accurately at 2100.

Because of the way 'accurate recording' is implemented, there is always
exactly one programme running on a channel; as one starts the previous one
stops.

BBC are very accurate with their signalling, the running status changes at
the beginning of the station ident immediately before the programme. ITV
and
C4/5 rather less so, and the Freeview channels seem to rely on clock time.

ITV1 sometimes starts recording a minute or so before the programme, and
stops when the programme starts.

--
Max Demian