LCD DVI Stuff

[kosh]

I'm contemplating purchasing an IIyama 5131 LCD Monitor at the end of
the month. I have noticed it has 2 DVI Interfaces.

Has anyone ever examined the different in image quality between
the analogue and digital inputs of an LCD Monitor ?

Does anyone have an idea of how dificult it would be to implement a DVI
output graphics card in an Iyonix or Viewfinder RISCPC ?

Does using the analogue input affect the frame rate of an LCD monitor ?


Kosh


--

[Sendu Bala]

On 12 Jul, kosh wrote:
I'm contemplating purchasing an IIyama 5131 LCD Monitor at the end of the month. I have noticed it has 2 DVI Interfaces. Has anyone ever examined the different in image quality between the analogue and digital inputs of an LCD Monitor ?

I have a WinPC connected to this LCD via DVI, and an Iyonix via
analogue. Certainly the Windows desktop is much sharper - not only the
text, but single pixel lines are actually single pixel lines, unlike
RISC OS which displays with very slight fringing on vertical lines.

Does anyone have an idea of how dificult it would be to implement a DVI output graphics card in an Iyonix or Viewfinder RISCPC ?

Don't know how difficult, but I dearly wish someone would make such a
card.

Does using the analogue input affect the frame rate of an LCD monitor ?

No.


--
Sendu Bala sendu@sendu.co.uk | http://www.sendu.co.uk/

Tori Amos, Rurouni Kenshin, DNA and my Iyonix
"If life gets any better than this, I'll be genuinely surprised"

[Ian Molton]

On Sat, 12 Jul 2003 08:06:37 +0100
Sendu Bala <sendu@sendu.co.uk> wrote:
I have a WinPC connected to this LCD via DVI, and an Iyonix via analogue. Certainly the Windows desktop is much sharper - not only the text, but single pixel lines are actually single pixel lines, unlike RISC OS which displays with very slight fringing on vertical lines.

Do you have a RPC with neutered video output?

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

[Steven Pampling]

In article <20030712094142.3b56bef9.spyro@f2s.com>,
Ian Molton <spyro@f2s.com> wrote: On Sat, 12 Jul 2003 08:06:37 +0100 Sendu Bala <sendu@sendu.co.uk> wrote:
I have a WinPC connected to this LCD via DVI, and an Iyonix via analogue. Certainly the Windows desktop is much sharper - not only the text, but single pixel lines are actually single pixel lines, unlike RISC OS which displays with very slight fringing on vertical lines.
Do you have a RPC with neutered video output?

Which part of the sentence "... and an Iyonix via analogue." brought RPC's
to your mind?
:-)

[Mech]

In message <20030712094142.3b56bef9.spyro@f2s.com>
, Ian Molton <spyro@f2s.com> wrote:
On Sat, 12 Jul 2003 08:06:37 +0100 Sendu Bala <sendu@sendu.co.uk> wrote:
I have a WinPC connected to this LCD via DVI, and an Iyonix via
^^^^^^ analogue. Certainly the Windows desktop is much sharper - not only the text, but single pixel lines are actually single pixel lines, unlike RISC OS which displays with very slight fringing on vertical lines.
Do you have a RPC with neutered video output?


--
__ _______ ___ __ __
/ |/ / __/ __// // / # Dan Maloney.
/ /|_/ / _// /_ / _ / # Disclaimer: I'm often wrong.
/_/ /_/___/\__//_//_/ # mailto:mech@toth.org.uk

[Ian Molton]

On Sat, 12 Jul 2003 15:26:49 +0100
Steven Pampling <steve.pampling@argonet.co.uk> wrote:
Do you have a RPC with neutered video output? Which part of the sentence "... and an Iyonix via analogue." brought RPC's to your mind? :-)

Doh. ok then I'll just put it down to nVidia suckkiness ;-)


--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

[Philip Pemberton]

In message <812ed6104c.Sendu@sendu.co.uk>
Sendu Bala <sendu@sendu.co.uk> wrote:
On 12 Jul, Ian Molton wrote: Do you have a RPC with neutered video output? I don't know what you mean. What has an RPC to do with this anyway?
In the later Mk2 and Mk3 RISC PC motherboards, Acorn added a set of filters
that reduced the bandwidth of the RISC PC's video output. After the LC
filters are removed, the video output quality is increased dramatically.

Later.
--
Phil.
philpem@despammed.com <<-- This address is valid
http://www.philpem.dsl.pipex.com/
.... A fail-safe circuit will destroy others.

[Andrew Hodgkinson]

On 12 Jul 2003 2:43, kosh wrote:
Has anyone ever examined the different in image quality between the analogue and digital inputs of an LCD Monitor ?

After Pace booted me out of Ditton House, I spent some redundancy cash
on a nice (but by 1600x1200 panel standards, bargain baserment) 19"
Iiyama LCD display. Win2K into the analogue input versus the same
Windows display into the digital is an interesting test. To be honest,
it's no competition; the analogue display was sharp and bright compared
to my weary old AKF85, whilst the digital display had me staring in
astonishment. It's exceptional, and considerably better than analogue
(even though analogue is still pretty good).

I wanted to know how RISC OS' anti-aliased fonts etc. would look on
something like that but no DVI output provided little opportunity until
I had cause to buy VA5000. It looks nice :-) but of course I can't run
VA5000 at the full panel resolution as such resolutions are not
supported in the emulator.
Does using the analogue input affect the frame rate of an LCD monitor?

LCD monitors often have response times which are considerably more
sluggish than the typical refresh rate of CRT displays. The distinctly
average 30ms response time on my own panel means it can display 1000/30
= about 33 frames per second. It simply cannot show anything more than
that. I run it in 1600x1200x16M at 60Hz, as a reasonably close multiple
of the panel abilities and a reasonable match to typical internet video
frame rates - most video clips are NTSC-esque 30fps, or a simple
fraction of that.

It *could* happily go down to rates like 40fps without seeing flicker
given this display persistence. This means you can in theory get a very
high resolution out of the host machine as it doesn't have to achieve a
high frame rate. I've done this at the Risc PC end - I used to run it
with a really dodgy 1600x1200x60fps hand-crafted mode definition, which
used nasty out-of-spec border timings etc. to fit within the VIDC's
capabilities. I've been able to relax that to 50fps now and get a nice
set of timings that the monitor and machine are both pretty happy about.

If you are planning on using modes that do not match your panel's
resolution make sure:

(A) you don't mind having no scaling of the display, so larger screen
modes simply won't work and smaller modes will have black borders
all around them; or:

(B) your graphics card or LCD panel can scale the incoming video to
fit the whole panel area, and that this scaling doesn't produce
really irritating visual artifacts.

Bear in mind that an LCD panel with something much worse than a 20ms
response time simply cannot display high frame rates, so animated items
will in general look less "smooth" than with CRT (20ms response gives
1000/20 = 50fps, same as PAL TV but without the interlace, which should
look fine - at 30ms -> 33fps, things can look a bit "sticky"). The
overall brightness of the panel is rarely an issue for an LCD monitor
unless you're planning on viewing it outdoors with the sun shining
straight on it ;-) but the contrast range is an issue. The better it is,
the closer to "black" black areas will get (since LCD displays light up
by shining a light *through* the display, true dark black isn't really
possible as some of the back lighting always leaks through).

--
TTFN, Andrew

"Hold on tight, lad, and think of Lancashire Hotpot!" - A Grand Day Out