Best tv for pc resolution
 

" wrote:

I _have_ seen VGALCD which wasn't pixel perfect. I agree it's
possible (easy?) to get it wrong. However, these Samsungs have some
kind of auto calibration which matches the pixels of the input signal
to those on the display. It seems to work consistently throughout the
various PCs with various Samsung panels throughout our office. The
exception is for the people who insist on running at 1024x786!

Now that's something to bear in mind when buying LCD monitors. VGA
inputs still seem to be present on most LCD monitors in the shops -- and
that auto-synchronisation would have be a pretty fundamental feature if
the displayed lines are not to be blurred. Is it just on Samsungs, or
can it be taken for granted on LCD monitors?

--
Dave Farrance

Best tv for pc resolution
 

On Mon, 01 Oct 2007 01:48:04 -0700, "
wrote:

1280x1024x75fps=98M pixels/sec
1920x1080x50fps=104M pixels/sec

The former is what I'm running right now. VGA connection. Samsung
SyncMaster 192V. Pixel perfect.

I _have_ seen VGALCD which wasn't pixel perfect. I agree it's
possible (easy?) to get it wrong.

Yep. That's pretty-much exactly my experience also. The interface
certainly can work with flat-panel monitors, but as the horizontal
resolution increases, the chances of problems occurring on a randomly
chosen source/display pair also increase. I've never had a problem at
or below 1280X1024, but I've seen some very disappointing results at
1360X768 and above. At 1920X1080, I certainly wouldn't risk having
15pin VGA as my only available interface.

However, these Samsungs have some
kind of auto calibration which matches the pixels of the input signal
to those on the display. It seems to work consistently throughout the
various PCs with various Samsung panels throughout our office. The
exception is for the people who insist on running at 1024x786!

That's great, if it works, but you obviously can't expect it to be
present in every display. The manufacturers of HDTVs in particular
don't have much incentive to include it since the TV already has other
interfaces which are actually designed with discrete pixels in mind,
and don't need such sticking plasters.


btw, you seem convinced that it's the horizontal pixel count that
matters -

Yep - convinced by personal experience.

if you think for one second about the analogue signal,
you'll realise it's the pixel clock that defines the bandwidth
required. This is roughly proportional to the pixel count per second
(not exactly, because blanking and sync varies with display mode in a
not quite proportional way on "old" modes).

But if you increase your one second of thought to maybe two or three,
you'd realize that the situation is more complex than bandwidth alone.
With no pixel sync on the interface, and a display with discrete
pixels that need to be addressed individually, timing becomes
crucially important too.

There's a line sync, so that lets vertical resolution off the hook.
Horizontally though, you're into trying to locate the middle of a
pixel when your last proper timing reference might have been nearly
two thousand pixels ago. Any bandwidth limitations will make matters
worse by tightening the margin for error on finding the exact centre
of each pixel.

Oscillators that can acheive the necessary accuracy over the required
temperature range are certainly available, but how many video cards
and TVs have them fitted?

Cheers,

Colin.

Best tv for pc resolution
 

In article , Colin Stamp
wrote:
There's a line sync, so that lets vertical resolution off the hook.
Horizontally though, you're into trying to locate the middle of a
pixel when your last proper timing reference might have been nearly
two thousand pixels ago. Any bandwidth limitations will make matters
worse by tightening the margin for error on finding the exact centre
of each pixel.

Assuming a required accuracy of 1 deg at 4.433MHz, oscillators in TV
sets can manage 1 part in about a hundred thousand when the last timing
reference was 64 microseconds ago. They've been doing it for years.

Rod.

Best tv for pc resolution
 

In article ,
Roderick Stewart wrote:
In article , Colin Stamp
wrote:
There's a line sync, so that lets vertical resolution off the hook.
Horizontally though, you're into trying to locate the middle of a
pixel when your last proper timing reference might have been nearly
two thousand pixels ago. Any bandwidth limitations will make matters
worse by tightening the margin for error on finding the exact centre
of each pixel.

Assuming a required accuracy of 1 deg at 4.433MHz, oscillators in TV
sets can manage 1 part in about a hundred thousand when the last timing
reference was 64 microseconds ago. They've been doing it for years.

and since the start of colour it's been 1 part in 10e6. (1 part in a
million). When timing the lines to and from studios we worked to an
accuracy of 10ns - and that was nearly 40 years ago.

--
From KT24 - in "Leafy Surrey"

Using a RISC OS computer running v5.11

Best tv for pc resolution
 

On Mon, 01 Oct 2007 18:34:08 +0100, Roderick Stewart
wrote:

In article , Colin Stamp
wrote:
There's a line sync, so that lets vertical resolution off the hook.
Horizontally though, you're into trying to locate the middle of a
pixel when your last proper timing reference might have been nearly
two thousand pixels ago. Any bandwidth limitations will make matters
worse by tightening the margin for error on finding the exact centre
of each pixel.

Assuming a required accuracy of 1 deg at 4.433MHz, oscillators in TV
sets can manage 1 part in about a hundred thousand when the last timing
reference was 64 microseconds ago. They've been doing it for years.


And what does that oscillator have to do with clocking in the pixels
on the VGA interface?

Like I said in the bit you thoughtfully snipped, oscillators that can
achieve the necessary accuracy over the required temperature range are
certainly available. It's just a matter of whether or not the money
gets spent to fit them both in the TV and on the video card. I can't
see the manufacturer of the average 20 quid video card spending out
for an off-the-shelf high-accuracy oscillator, nor can I see them
fretting too much over the temperature compensation of a discrete
setup.

Cheers,

Colin.

Best tv for pc resolution
 

On Mon, 01 Oct 2007 18:53:16 +0100, charles
wrote:

In article ,
Roderick Stewart wrote:
In article , Colin Stamp
wrote:
There's a line sync, so that lets vertical resolution off the hook.
Horizontally though, you're into trying to locate the middle of a
pixel when your last proper timing reference might have been nearly
two thousand pixels ago. Any bandwidth limitations will make matters
worse by tightening the margin for error on finding the exact centre
of each pixel.

Assuming a required accuracy of 1 deg at 4.433MHz, oscillators in TV
sets can manage 1 part in about a hundred thousand when the last timing
reference was 64 microseconds ago. They've been doing it for years.

and since the start of colour it's been 1 part in 10e6. (1 part in a
million). When timing the lines to and from studios we worked to an
accuracy of 10ns - and that was nearly 40 years ago.

Interesting, but irrelevant.

Cheers,

Colin.

Best tv for pc resolution
 

In article , Colin Stamp
wrote:
And what does that oscillator have to do with clocking in the pixels
on the VGA interface?

Like I said in the bit you thoughtfully snipped, oscillators that can
achieve the necessary accuracy over the required temperature range are
certainly available. It's just a matter of whether or not the money
gets spent to fit them both in the TV and on the video card. I can't
see the manufacturer of the average 20 quid video card spending out
for an off-the-shelf high-accuracy oscillator, nor can I see them
fretting too much over the temperature compensation of a discrete
setup.

Snipping nothing this time, I was just trying to point out that crystals
with an accuracy and stability greatly exceeding what you say is
necessary are already routinely fitted to millions of circuit boards in
very mundane products, and have been for some time, so I can't see why
it would be a problem to fit them in modern displays. Crystal
oscillators are not particularly special at all.

Rod.

Best tv for pc resolution
 

Colin Stamp wrote:
On Sun, 30 Sep 2007 19:40:07 GMT, "ThePunisher"
wrote:

Andrew wrote:
On Tue, 25 Sep 2007 20:19:09 +0100, Colin Stamp
wrote:

You're agreeing, yet you haven't tried it any more than he has.

Thousands of people use 1080P via VGA on XBox 360's.

And some people use 1080p over component

And these are *all* pixel-perfect (as a PC display needs to be) are
they?


May be it's the newsreader I'm using but the words "pixel-perfect" don't
seem to exist in your original post.

--
ThePunisher

Best tv for pc resolution
 

On Mon, 01 Oct 2007 22:33:45 +0100, Roderick Stewart
wrote:

In article , Colin Stamp
wrote:
And what does that oscillator have to do with clocking in the pixels
on the VGA interface?

Like I said in the bit you thoughtfully snipped, oscillators that can
achieve the necessary accuracy over the required temperature range are
certainly available. It's just a matter of whether or not the money
gets spent to fit them both in the TV and on the video card. I can't
see the manufacturer of the average 20 quid video card spending out
for an off-the-shelf high-accuracy oscillator, nor can I see them
fretting too much over the temperature compensation of a discrete
setup.

Snipping nothing this time, I was just trying to point out that crystals
with an accuracy and stability greatly exceeding what you say is
necessary are already routinely fitted to millions of circuit boards in
very mundane products, and have been for some time, so I can't see why
it would be a problem to fit them in modern displays. Crystal
oscillators are not particularly special at all.

Rod.

It's only a problem for the bean counters. Alas, bean counters abound.
There's not much incentive to do it anyway. If they spend an extra
couple of quid or whatever and fit an oscillator that's well up to the
job, then claim that the TV can handle 1920X1080 on the VGA port, how
many extra TVs will that sell? How many complaints will it bring in
from customers who plug in cheap video cards and find it doesn't work?

The alternative is to save a bit of money, down-spec the resolution of
the VGA input and expect anyone that wants full resolution to use an
interface that was designed for the job from the outset rather than
one that's now well into "legacy" status.

Cheers,

Colin.

Best tv for pc resolution
 

On Mon, 01 Oct 2007 21:48:35 GMT, "ThePunisher"
wrote:

Colin Stamp wrote:
On Sun, 30 Sep 2007 19:40:07 GMT, "ThePunisher"
wrote:

Andrew wrote:
On Tue, 25 Sep 2007 20:19:09 +0100, Colin Stamp
wrote:

You're agreeing, yet you haven't tried it any more than he has.

Thousands of people use 1080P via VGA on XBox 360's.

And some people use 1080p over component

And these are *all* pixel-perfect (as a PC display needs to be) are
they?


May be it's the newsreader I'm using but the words "pixel-perfect" don't
seem to exist in your original post.

Maybe you don't require your PC display (that's what this thread is
about, remember) to be pixel-perfect. We'd have to agree to disagree
on that one.

Cheers,

Colin.