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uk.tech.digital-tv (Digital TV - General) (uk.tech.digital-tv) Discussion of all matters technical in origin related to the reception of digital television transmissions, be they via satellite, terrestrial or cable. Advertising is forbidden, with no exceptions.

So retune day ishere..



 
 
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  #13  
Old August 2nd 17, 01:56 PM posted to uk.tech.digital-tv
NY
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Posts: 1,187
Default So retune day ishere..

"Chris Hogg" wrote in message
...
On Wed, 2 Aug 2017 09:45:11 +0100, "Brian Gaff"
wrote:

Should I expect it now or wait till tonight?
Brian


I retuned at today 12.30pm, with some odd results. We receive from the
Praa Sands relay, so a limited range of channels and no HD. We have a
Humax PVR feeding a Samsung TV via SCART. I retuned the TV first, and
a quick check on Channel 130 told me that it had moved to Channel 231,
as expected. Then I went over to the Humax, which by chance was set on
Channel 130, but was receiving that channel as normal, as if nothing
had changed with the signal. I retuned it anyway, and then when I went
back to Channel 130, it was no longer there and had been replaced by
the same message that it had moved.

I don't understand. How can Channel 130 not be there after I've
retuned on one device, but be there if I haven't retuned on another.
Surely either the transmitter is putting out the signal, or it isn't.


On my TV, after a retune, the old channel (eg 130 for BBC NEWS) bring up a
static page saying what the new LCNs are for the various channels. On a
TV/PVR that has not yet been retuned, you still get the channel on the old
LCN. I presume that it's to allow a period of overlap in which to retune.

It's frustrating if you *have* retuned because the "dead wood" is still
there. Using TSReader I've been looking at the list of channels in each mux
and the old ones are still there. I wonder how long it will be before they
are removed.

  #14  
Old August 2nd 17, 02:33 PM posted to uk.tech.digital-tv
Terry Casey[_2_]
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Posts: 738
Default So retune day ishere..

In article
,
says...

On my TV, after a retune, the old channel (eg 130 for BBC
NEWS) bring up a static page saying what the new LCNs are
for the various channels. On a TV/PVR that has not yet
been retuned, you still get the channel on the old LCN. I
presume that it's to allow a period of overlap in which to
retune.


Surely the point is that nothing has changed from a
transmission point of view? The programmes themselves are
still being transmitted in the same position within each
transport stream as before and it is just the LOGICAL
channel number that has changed.

Each device stores all the information relevant to all the
programmes when you retune, including the logical channel
number. Thus, if you don't retune, you continue to use the
'old' number but it still correctly points to the correct
incoming portion of the signal and will continue to do so in
perpetuity, provided that the transmission sequence remains
unchanged.

If you retune a different receiver, it will store the new
look-up table in its memory and the old number no longer
points to a valid transmission but to the static page you
are seeing.

After ITV first started, most sets were equipped with 13
channel turret tuners. In the London area, BBC was on
channel 1 and ITV was on channel 9, which also happened to
correspond to the first and ninth positions on the turret.

Later on, some manufacturers, realising that the same
pairing existed in different parts of the country, started
producing sets where the channel sequence went 1, 9, 2, 10,
3, 11 and so on so that it only took one click forwards or
backwards to change channel. If you continued to click round
nine positions from the BBC position, you now received
nothing - (the technology to display a messge telling you
what you had done wrong didn't exist in those days!)

However, as the two programmes were now on the first and
second positions of the turret, the actual transmissions
were still on channels 1 and 9.

There's nothing new under the sun, they say!


--

Terry
  #16  
Old August 2nd 17, 02:49 PM posted to uk.tech.digital-tv
NY
external usenet poster
 
Posts: 1,187
Default So retune day ishere..

"Terry Casey" wrote in message
...
In article
,
says...

On my TV, after a retune, the old channel (eg 130 for BBC
NEWS) bring up a static page saying what the new LCNs are
for the various channels. On a TV/PVR that has not yet
been retuned, you still get the channel on the old LCN. I
presume that it's to allow a period of overlap in which to
retune.


Surely the point is that nothing has changed from a
transmission point of view? The programmes themselves are
still being transmitted in the same position within each
transport stream as before and it is just the LOGICAL
channel number that has changed.

Each device stores all the information relevant to all the
programmes when you retune, including the logical channel
number. Thus, if you don't retune, you continue to use the
'old' number but it still correctly points to the correct
incoming portion of the signal and will continue to do so in
perpetuity, provided that the transmission sequence remains
unchanged.


Is that actually true even after the old LCN record is removed from the
relevant table in the stream? I imagine this will happen fairly soon to
avoid the list of channels that a TV displays being cluttered up with all
the dead ones. After all, the whole point of the renumbering is to free up
LCNs in other numbering ranges.

What annoys me is that channels like the news channels have already moved
once, a few years ago: BBC News used to be on an LCN in the 80s (IIRC), then
it changed to 130 and now it's moved again.

The central authority that assigns LCNs really ought to have done the job
correctly the first time, leaving enough space between genres of channels
than no further renumbering was necessary.

Maybe I'm unusual, but I always change channels by entering the LCN, rather
than by scrolling up and down the list - unless it's only one or two
channels away from the present one. Having to learn new LCNs is a hassle.


As for PVRs, a lot depends on how the software has been written. If it uses
the stream ID (which probably remains the same forever proving the channel
remains on the same mux) then there's no problem. However if it uses the LCN
then it will have a timer event which points to the wrong channel.

  #18  
Old August 2nd 17, 03:48 PM posted to uk.tech.digital-tv
Max Demian
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Posts: 3,800
Default So retune day ishere..

On 02/08/2017 09:45, Brian Gaff wrote:
Should I expect it now or wait till tonight?


http://terrestrialtv.uk/newlcn shows the changes, but I think you can
carry on using the old numbers on a non-retuned set.

--
Max Demian
  #19  
Old August 2nd 17, 05:53 PM posted to uk.tech.digital-tv
Andy Burns[_12_]
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Posts: 379
Default So retune day ishere..

Max Demian wrote:

I think you can
carry on using the old numbers on a non-retuned set.


And if you /do/ retune, looks like you'll end up with dozens of
place-holder channels saying

"GodSquad2 has now moved to channel NNN"
"CheapSlappers is now on channel YYY between 03:35 and 04:25"
  #20  
Old August 2nd 17, 08:23 PM posted to uk.tech.digital-tv
Andy Burns[_12_]
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Posts: 379
Default So retune day ishere..

Yellow wrote:

What is changing?


Certainly not much variation across the BBC "local" radio stations, at
the moment the same chap (Georgey Spanswick? Google seems to think it
should be a woman) seems to be on

BBC Derby
BBC Northampton
BBC Lincolnshire
BBC Leicester
BBC Nottingham
BBC Coventry & Warwickshire
BBC Hereford & Worcester
BBC Humberside
BBC Norfolk
BBC Sheffield
BBC Stoke
BBC West Midlands

Which is all that I receive, are there other presenters in different
local groups, or is it effectively a national show?
 




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