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Dashed lines at top of plasma TV

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Dashed lines at top of plasma TV

I've recently noticed some channels carry some dashed lines at the top of the screen as in attached photo.
Doing a little research it seems that it is down to how some broadcasters don't do 1:1 pixel mapping. At the moment I can only see it Dave ja vu but, strangely, not Dave.
Turning Overscan on rids it but, obviously, I don't want to do that. It's only really obtrusive when it's a dark scene.
Anyone seeing this on their TVs? Can it be see on LEDs as well?

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Re: Dashed lines at top of plasma TV

I always thought it was something to do with TELETEXT transmissions on the old t.v...  don`t know what it is for with present t.v. 
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Re: Dashed lines at top of plasma TV

It's the timecoding for transmissions, not entirely sure what they use it for myself, presumably it's something that the broadcasters use for their tape players...
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Re: Dashed lines at top of plasma TV

Yes it is. Nice explanation here..  It's visible because of the lack of overscan.
http://www.philrees.co.uk/articles/timecode.htm
EDIT: How old is the set? Have you got the aspect ratios mismatched between the decoder (if there is a separate one) and the tv?
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Re: Dashed lines at top of plasma TV

The TV is just over 4 years old.
I can't say I have noticed it when watching from YouView but, then again, I rarely record any of the channels it seems to effect.
I did notice it on a Freesat channel this morning but can't remember which one now. Only seen it on SD channels, though.
It's not a major issue for me as just wondering if it was only plasmas - it appears not - or if others noticed it, too.

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pwatson
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Re: Dashed lines at top of plasma TV

It's not timecode (VITC), it's widescreen switching (WSS)  This is data on line 23 of SD transmissions to describe the aspect ratio of the transmitted video.