Upscaling

"brightside S9" wrote in message
...
On Tue, 24 Nov 2015 21:08:27 +0000, Vir Campestris
wrote:

On 24/11/2015 01:13, alan_m wrote:
A better picture may also be produced if over scanning on a TV is
turned
off.

Why would anyone turn it on on an LCD or Plasma display? It's there
to
allow for CRT geometry errors.

It is on by default on some sets, e.g. my Panasonice LCD of about
5yrs
vintage.



+1


--
Woody

harrogate3 at ntlworld dot com

On 25/11/2015 00:00, UnsteadyKen wrote:

In article:

Richard Tobin says...

At times some channels have annoying black and white rectangles at the
top of the screen without it. For example, Dave Ja Vu has right now
(Dave doesn't).

Talking Pictures has these rectangles too.

Rectangles ? You mean the Line 23 pulses breaking through perhaps ?



--
Mark
Please replace invalid and invalid with gmx and net to reply.

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On Wed, 25 Nov 2015 07:34:49 +0000, Woody wrote:

"brightside S9" wrote in message
...
On Tue, 24 Nov 2015 21:08:27 +0000, Vir Campestris
wrote:

On 24/11/2015 01:13, alan_m wrote:
A better picture may also be produced if over scanning on a TV is
turned off.

Why would anyone turn it on on an LCD or Plasma display? It's there to
allow for CRT geometry errors.

It is on by default on some sets, e.g. my Panasonice LCD of about 5yrs
vintage.



+1

It's possibly an option to hide the edges of the picture where the
compression artefacts appear more obvious to the eye. The over-scanning
(or zooming) doesn't have to be as extreme as used to be used in CRT
based TV sets, just enough to place the outer half of these picture
blocks on the edge of the display to hide the half that was worse
affected by the compression artefacts.

I can't say I've noticed this defect of compression at the picture edges
in recent years so they may have improved the compression algorithms to
mitigate this problem sufficiently to avoid the need to over-scan them
off the edges of the display. Now may be the time to turn off any such
over-scanning options that may have been set by default in older models
of flat screen TVs.

--
Johnny B Good

On 26/11/2015 14:38, Johnny B Good wrote:

It's possibly an option to hide the edges of the picture where the
compression artefacts appear more obvious to the eye. The over-scanning
(or zooming) doesn't have to be as extreme as used to be used in CRT
based TV sets, just enough to place the outer half of these picture
blocks on the edge of the display to hide the half that was worse
affected by the compression artefacts.

I can't say I've noticed this defect of compression at the picture edges
in recent years so they may have improved the compression algorithms to
mitigate this problem sufficiently to avoid the need to over-scan them
off the edges of the display. Now may be the time to turn off any such
over-scanning options that may have been set by default in older models
of flat screen TVs.

One thing lack of overscan reveals are some vision mixers about to
perform a digital effect. The foreground image is often one pixel/line
smaller on all four sides, making the 'next' image visible around the
edge. Sony vision mixers suffer from this, there's a (reasonably) good
reason for this that I was given my one of their designers once, but I
can't remember what it was !


--
Mark
Please replace invalid and invalid with gmx and net to reply.

On 01/12/2015 11:55, pamela wrote:
On 21:03 23 Nov 2015, Bill Wright wrote:

I've never thought much to the idea, but I must say my wife's new Humax
Freeview box really does make SD programmes look good. It was however
necessary to adjust the contrast and brightness on the telly.

Bill

How can upscaling improve a picture?

It can't add information that wasn't there in the original, but it can
make a good or bad job of converting the resolution. It appears that the
Humax does it better than the Sony TV. I think it's more about hiding
artefacts than anything else.

Wouldn't any improvement be due to the different tuner rather than
upscaling itself?

Not the tuner.

Bill