[mythtv-users] overscan problems with nvidia 8400 GS

[Tortise]

"The more I find out, the more I think we've been sold a pup here."

The more I looked at this the more I also came to this conclusion.  How many people paid good money to upgrade their TV's when they 
weren't delivered what they should have been - and how many might then have not needed to upgrade?  Why should I pay to upgrade when 
a perfectly good set with distinct advantages over LCD would do me much longer if it did what it was promoted to?

For the record CRT displays have a number of advanctages over LCD - better color depth, better blacks, better viewing angles, wider 
refresh rate ranges, less reflection etc...  Shame the Manufacturers of HD CRT's did not always ensure the whole HD picture was 
actually displayed, although they were quick to promote the HD specifications and not say there was any downscaling, overscanning 
loss of definiton etc.  LCD's also have some positive points however a good HD CRT is just that, very good.  (Heavy and hard to 
move - but what do you buy it for, to move around a lot - or to watch a quality image on?)

"On digital signals, why any need for overscan at all ?"

It has been observed in this thread that there can be "edge effects" and a small amount of overscan can correct this.  I agree with 
that, one line at the edge, even one pixel wide, that is out of sync with the rest of the image is extremly distracting and 
annoying.  Scaling the image to hide those annoying lines is a necessary evil - a volume like slider is all that is required to 
scale the small required amount.  Thats all.  Certainly much less than 19% of a HD image needs to be hid.

Regarding the question of "I suspect the standard doesn't specify how many pixels the panel itself has"....

 I believe this is frankly incorrect, the standards are extremely precise, see my other posts of the moment detailing and clarifying 
this.

"Why not produce a 1776x1000 panel for a 1080 set and avoid the rescaling altogether ? I guess I can answer that myself - our less 
educated brothers (and sisters) would probably then refuse to buy it as not being "full 1080" :("

Well this in reality is a good description of what has occurred in a number of TV's, so despite your faith in your "brothers (and 
sisters) would probably then refuse to buy" in fact they did buy as the distinction was not clear to them and they didn't know 
better.  I do wonder if one major reason that overscanning has continued for so long is that if they took it away earlier that would 
make the difference much more obvious - and people may well have started seeing they'd been duped and start complaining earlier...!



----- Original Message ----- 
From: "Simon Hobson" <linux at thehobsons.co.uk>
To: "Discussion about mythtv" <mythtv-users at mythtv.org>
Sent: Monday, July 13, 2009 6:55 PM
Subject: Re: [mythtv-users] overscan problems with nvidia 8400 GS



I think it means exactly that ! How completely f***ing crazy can it
be to define a standard where the source can supply a high quality
digital signal that's been scaled to the right size in the decoding
section (ie where it will create the least artifacts) - and then
resample it to guarantee some distortion of the picture !
Though to be fair, I suspect the standard doesn't specify how many
pixels the panel itself has - in which case, it seems crazy that
manufacturers produce panels with 'non native' resolutions. Why not
produce a 1776x1000 panel for a 1080 set and avoid the rescaling
altogether ? I guess I can answer that myself - our less educated
brothers (and sisters) would probably then refuse to buy it as not
being "full 1080" :(


-- 
Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.
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