Dots on BBC1 Sky widescreen picture

Hi,

In article ,
Paul wrote:
Sorry if this has already been covered (I did look), but is anyone else
getting a line of dots at the top of the picture (not screen) on BBC1
widescreen transmissions via Sky, since the BBC went regional? They look
like data (like the Teletext lines in an analogue transmission) and don't
appear on other BBC channels. They're just annoying on our main (4:3) telly,
but our portable flickers so badly on digital BBC1 now (RF or Scart
connection) that we don't watch it.

Not sure if they've been mentioned here, but they have on Digital Spy's
forums.

I think the BBC are aware of it and trying to sort it. I agree though, it's
a little annoying.

Andy

Paul Stephens wrote:
Sorry if this has already been covered (I did look), but is anyone
else getting a line of dots at the top of the picture (not screen) on
BBC1 widescreen transmissions via Sky, since the BBC went regional?
They look like data (like the Teletext lines in an analogue
transmission) and don't appear on other BBC channels. They're just
annoying on our main (4:3) telly, but our portable flickers so badly
on digital BBC1 now (RF or Scart connection) that we don't watch it.

They are line 23 widescreen signalling idents. I assume they are used
*internally* within the BBC networks to flag the correct aspect ratio. It seems that
they are not getting stripped off before transmission (they should be).

Some Digiboxes pass the signal, and it gets displayed, others do not. Some TV sets
(notably early Sony w/s sets) respond incorrectly to some of the signals. For instance
my 1996 Sony displays a stretched image, when it receives the 4:3 line 23 signal. Very
annoying. I have to go back to BBC 1 London on 944 during 4:3 programmes.

(BBC 1 London, Scotland, Wales, and NI, plus all BBC 2s and 3, 4, N24 do not
have the signal, thank goodness ! )

Previously, in uk.media.tv.sky:

Chris Vowles said:

BBC are not sure why it is happening!
see http://www.bbc.co.uk/reception/dsatanswers.shtml#epg

They think it's receiver related.

Er, I've got Sky+, first generation box admittedly, but isn't that
supposed to be top of the range? What sort of box do you need to avoid
the line?

Can anyone find an email link where I can tell them to blank line 23?
It's not difficult.

My solution is to move my series links to BBC London as I have a
widescreen tv downstairs which isn't affected - it's only when I watch
Stenders on the portable 4:3 upstairs that I see it.


--
Jack Bristow
To contact me, bypass SD6

In article ,
Chris Vowles wrote:
BBC are not sure why it is happening!
see http://www.bbc.co.uk/reception/dsatanswers.shtml#epg

They don't know what it is? It looks like line 23 signalling to me...

Dave
--
Email: MSN Messenger:

Ant wrote:
On Fri, 08 Aug 2003 16:09:39 +0100, Chris Vowles
wrote:

BBC are not sure why it is happening!

The BBC must be in a sad state if they can't recognise and know how to
insert/remove a line 23 WSS signal...

I understand it is a problem resulting from the specific MPEG2 encoders
used. The specific installation used to create a mixed 4:3/16:9 aspect
ratio DSat service from the permanent 16:9 DTT / Network services in the
regions requires line 23 signalling between an ARC (required to convert
12P16 to 12F12) and the MPEG2 coders. I think the encoders should probably
be programmable to strip WSS - but they don't seem to be.

Steve

Ant wrote:
On Fri, 08 Aug 2003 16:09:39 +0100, Chris Vowles
wrote:

BBC are not sure why it is happening!

The BBC must be in a sad state if they can't recognise and know how to
insert/remove a line 23 WSS signal...

I expect they've installed some new kit for these regional feeds, and the
removal or masking of the line 23 idents requires the equipment manufacturer
to make a (hopefully) software, or (hopefully not) hardware modification.
I know from my own experience working in broadcast equipment manufacture
and supply, that this can take time to sort out, test, and finally implement.

Mike Henry wrote:

wrote:
I understand it is a problem resulting from the specific MPEG2
encoders used. The specific installation used to create a mixed
4:3/16:9 aspect ratio DSat service from the permanent 16:9 DTT /
Network services in the regions requires line 23 signalling between
an ARC (required to convert 12P16 to 12F12) and the MPEG2 coders. I
think the encoders should probably be programmable to strip WSS -
but they don't seem to be.

Thanks very much for that info. What I don't understand though it why
the encoders were encoding line 23 at all. Ie, it's not a question of
"stripping" it from the picture, it isn't strictly part of the picture
in the first place!

The second half of line 23 is active picture however. The first half has been
hijacked in recent years for WSS switching (a PAL+ legacy)

It is often easier to either let all of L23 through, or none of it. It is used
extensively within many broadcaster's systems for WSS and other signalling.

See:-
http://www.microvideo.co.uk/home1.htm

Previously, in uk.media.tv.sky:

Mark Carver said:

Ant wrote:
On Fri, 08 Aug 2003 16:09:39 +0100, Chris Vowles
wrote:

BBC are not sure why it is happening!

The BBC must be in a sad state if they can't recognise and know how to
insert/remove a line 23 WSS signal...

I expect they've installed some new kit for these regional feeds, and the
removal or masking of the line 23 idents requires the equipment manufacturer
to make a (hopefully) software, or (hopefully not) hardware modification.
I know from my own experience working in broadcast equipment manufacture
and supply, that this can take time to sort out, test, and finally implement.

They could surely put something in line with the "kit" either in or
out of it to mask the line! They did enough DOG marked testing, why on
earth did noone spot this???


--
Jack Bristow
To contact me, bypass SD6

In article , jack.bristowSD6
@virginSD6.net says...
Previously, in uk.media.tv.sky:

Mark Carver said:

Ant wrote:
On Fri, 08 Aug 2003 16:09:39 +0100, Chris Vowles
wrote:

BBC are not sure why it is happening!

The BBC must be in a sad state if they can't recognise and know how to
insert/remove a line 23 WSS signal...

I expect they've installed some new kit for these regional feeds, and the
removal or masking of the line 23 idents requires the equipment manufacturer
to make a (hopefully) software, or (hopefully not) hardware modification.
I know from my own experience working in broadcast equipment manufacture
and supply, that this can take time to sort out, test, and finally implement.

They could surely put something in line with the "kit" either in or
out of it to mask the line! They did enough DOG marked testing, why on
earth did noone spot this???

Perhaps they were watching the tests on widescreen monitors/TVs where there's
a bit of overscan and so they won't spot it.

Will these also be spotted on a WS Plasma TV where there's no overscan either?
--

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/* http://DVDfever.co.uk (editor)
/* 937 DVDs, 259 games, 33 videos, 67 cinema films, 69 CDs, laserdiscs & news
/* catch me if you can, terminator 3, brute force, punch drunk love, shield s1
"Organiser Eric Amy hit out today after just four people showed up for
a public meeting to fight apathy in Dorchester" - Dorset Evening Echo

They could surely put something in line with the "kit" either in or
out of it to mask the line!

Contrary to popular belief TV stations do not have piles of spare equipment laying
about in order to perform instant fixes of this type. I can't think of any simple solution that
would mask line 23. Feeding the signal through a VTR might do it, but that would
be busy somewhere else being a VTR :-) With 15 or so feeds affected it is even
more unlikely that a bodge temporary fix could be initiated.

I do agree it is less than ideal that things have got to this stage, without the problem
being fixed.

They did enough DOG marked testing, why
on earth did noone spot this???

Perhaps they were watching the tests on widescreen monitors/TVs where
there's a bit of overscan and so they won't spot it.

Monitoring of pictures within broadcast stations should be done on
'underscanned' monitors, for this very reason. All broadcast quality
monitors have several display options. Overscan (like yer telly at home),
Underscan where line 23 (and lines 18-22) are clearly visible, V delay
where the entire vertical blanking area can be examined (so teletext data and
any other signals can be seen), and H delay so the sync pulses and
colour sub-carrier burst are visible. In addition often a waveform monitor
is also connected, this is rather like an oscilloscope where any part of the video signal can be
examined and measured .