Re: VGA Scan Conversion and Plasma Panels

["paul gordon" <paul_gordon@xxxxxxx>]

Keith,

"phew!"

Thanks for your comprehensive reply! I take all of your points.

I suppose I should have said, that although I was kinda disappointed, the
TV
display is more-or-less "useable" - I have set the desktop
resolution to
800x600, but have used large fonts, and a high-visibility colour scheme -
The major problem seems to be colour bleeding at the edges of images, and
general edge definition. Fortunately, being a laptop, I obviously have the
choice to switch between either the TV display or the LCD screen of the PC,
and for the most part, I tend to use the laptop panel, and switch it over
to
the TV just occasionally. When I'm using the TV, I can make out all the
desktop icons & icon text, and when I put Winamp in
"double-size" mode, I
can make out everything in Winamp clearly enough as well. Winamp use is
pretty much all I use it for at the moment. This laptop is just a temporary
measure though, I plan to put a full high-spec desktop machine in the TV
room, to use for:
- Web TV browsing
- MP3 jukebox
- CD player
- DVD player
- Games player
- Local HA control
However, when I come to do this, I won't have the luxury of an LCD panel,
so
I will have to use the TV as the only display device, so I'm keen to
optimise the quality of the displayed image...
I'm considering the new Matrox G400 twinhead as the display adapter in this
PC - this has been pretty well rated on Tom's Hardware Guide, and supports
_simultaneous_ TV and monitor outputs, and allows the resolution and
refresh
rates to be set independently for each. (So at least I'll have the option
of
hooking up an SVGA monitor as well, should I find I have to...) However, my
TV is now about 5 years old (which is pretty much what I consider the
expected lifespan of a TV), and so is up for replacement soon anyway. I was
planning to get something even bigger (current one is 33"), and now I
have
to consider the PC image display quality as well, so I'd like to choose
something that gives me a decent PC display.
I could live with standard old VGA, I suppose, if it were sharp and clear,
like on a PC monitor, but obviously I'd prefer to go to at least 800x600 (I
think much higher than this is pushing it on a TV!)
Anyway, needless to say, I won't be purchasing anything until I have had a
full demonstration, with my own equipment attached, and seen & judged
the
results for myself. - I reckon (hope?) that this process is no more that
6-9
months away (wife permitting), so as/when I go through the evaluation, I'll
report my findings back to the list. Hopefully, the market and the
technology will have moved on a bit by then anyway, so hopefully, I might
have a few more options...

Cheers!

Paul Gordon


>From: "Keith Doxey" <keith.doxey@xxxxxxx>
>Reply-To: ukha_d@xxxxxxx
>To: <ukha_d@xxxxxxx>
>Subject: [ukha_d] Re: VGA Scan Conversion and Plasma Panels
>Date: Fri, 23 Jul 1999 11:41:31 +0100
>
>Hi Paul,
>
>The whole are of VGA Scan conversion is a messy one.
>Here in the UK we are lucky that a PAL TV picture has 625 lines
(although
>not all of those are visible) and at a push can get a reasonable SVGA
>800x600 image on the screen. In the US they use NTSC which only has 525
>lines and so they are restricted to VGA 640x480 maximum.
>
>The quality of the displayed picture depends on a number of factors.
>
>1. the quality of the converter. Broadcast quality ones are in the
region
>of
>1000UKP and are obviously not in the same league as a 30 quid VGA gamer
>card.
>
>2. the quality of the tube in the TV. Just as PC monitors have
different
>dot
>pitch so do TV tubes. Look closely at the phosphor dots or stripes on
your
>TV and compare them in size to your PC monitor.
>
>If you are trying to display an image of higher resolution that the
display
>device can handle there will be loss of detail. This also happens with
LCD
>displays as well. Many of them compress a 1024x768 image to fit a
800x600
>LCD and the only way to display 1000 pixels of information in 800
physical
>locations is to throw 200 of them away ie drop every fifth pixel. The
>results of this can be awful. Tacky ACSII graphics follow....be sure to
use
>a fixed font like courier for this. This is an enlarged version of the
>letters A and E with a space between them
>
>How it should look
>
>  XXX  XXXXX
>X   X X
>X   X X
>XXXXX XXXX
>X   X X
>X   X X
>X   X XXXXX
>
>A well compressed image would look like this
>
>  XX  XXXX
>X  X X
>XXXX XXX
>X  X X
>X  X XXXX
>squashed a bit but still legible
>
>but many displays and converters do things like this
>
>  XXX XXXX
>X    X
>X    X
>XXXX XXXX
>X    X
>X    XXXX
>
>or
>
>XXX XXXXX
>    XX
>    XX
>XXXXXXXX
>    XX
>    XXXXXX
>
>doesnt look pretty does it :-((
>
>I havent tried using a Video card with TV output yet like the ATI All
in
>Wonder but I would imagine the results would be much better than any of
the
>converter cards or boxes out there due to the fact that the image was
being
>generated for display on a TV rather than converted from a higher
>resolution.
>
>It is possible to get good looking computer images on a TV. The Amiga
>produces a quite legible image at a fairly high resolution and even the
>humble BBC Micro from 1982 can display 80 character text on a TV which
is
>double the resolution of teletext. The only shortcoming of the BBC was
a
>poor PAL encoder but the RGB output is great.
>
>When looking at Projectors and Plasma Panels in the sub 4 grand
bracket,
>read the specification VERY carefully. Although they say they have a
VGA
>input for a PC people immeadiately think "great, I'll hook the Pc
up to
>it".
>With many of these lower cost units IT REALLY IS A VGA INPUT  640x480
MAX
>!!!
>
>We have just got 2 new 21" Mitsubishi Plasma screens at work and
they are
>Video, S-Video and VGA. NOT SVGA.
>
>Many of the 4:3 models will only do VGA
>the newer and more expensive 42" widescreen 16:9 panels are great
for
>movies
>but for PC the resolution is 852x480 which gives SVGA width but VGA
height.
>As I said in a previous post, the toolbars take up much of the height
at
>low
>resolutions so you still have a problem with not much display area.
Also
>for
>the widescreen plasma panels you need to find special video drivers to
>generate the correct aspect ration from your PC. Or suffer the effects
of
>stretching or compressing the image.
>
>The latest Pioneer 50" Widescreen panel is sold as XGA but is
actually
>1280x768 so a true XGA 1024x768 signal has black bars at the side or
you
>stretch it horizontally. If you run your PC at 1280 x 1024 then you
fill
>the
>width but the image is compressed vertically. It does look good on
video
>though ;-))
>
>Hopefully as TV and PC becomes more integrated the quality of tubes in
TV's
>will improve and so will the scan rates. Basic Multisync monitors now
cost
>that same or less than a 14" TV. Not long ago they were double the
price.
>There are now loads of graphics cards with TV outputs and converters
from
>30
>quid. Not long ago there were no cards with a TV output and the
cheapest
>converters were 100 pounds.
>LCD panels are plummeting in price. The highest resolution ones are now
>slightly cheaper than VGA panels were a couple of years ago.
>
>Prices are falling and products are becoming available, the trouble is
we
>are too far ahead of Joe Public in our persuit of technology and so
have to
>wait for it to appear, or pay the high prices currently demanded.
>
>Keith
>
>Keith Doxey
>http://www.btinternet.com/~krazy.keith
>Krazy Keith's World of DIY HomeAutomation
>
>
> > -----Original Message-----
> > From: paul gordon [mailto:paul_gordon@xxxxxxx]
> >
> >
> > I can add a little more to the displaying of VGA on a TV
dilemma...
> >
> > I currently do this with my old laptop (an IBM Stinkpad), which
> > has a custom
> > connector for a video-out port (a tiny little 3pin plug), into
which
> > connects a "dongle" with a breakout box on it which has
both a phono
> > (composite) and a mini-din (S-VHS) video out connectors. I have
> > used both of
> > these ports, and to be honest have been disappointed with the
results. I
> > expected to see an improvement when I changed it from the
> > composite to the
> > S-video connection, but in truth, I can't really tell any
difference.
> >
> > However, I was recently at Microsoft Tech-Ed in Amsterdam,
> > I noticed that the display quality on these was
> > considerably higher than I achieve at home, so I took a look
> > round the back
> > of one to see how it was connected, and sure enough, despite a
> > plethora of
> > connectors on the back, the ONLY signal wire going in to them was
a
>co-ax
> > UHF lead... These were perfectly standard Philips domestic TV's
(not
> > specialised monitors.) My assumption is that, being Philips TV's,
> > they are
> > most likely 100Hz scan models, (which my current TV isn't). I'm
guessing
> > that this may be the reason for the better image quality...
> >
> > Can anyone else comment on this? - has anyone tried comparing the
> > same PC's
> > TV out signal between a 50Hz and a 100Hz scan TV? (I'd prefer to
know if
> > it's worth it before I rush out & buy one!)
> >
> > but then in this month's T3 I spotted an ad for a 60"
> > (Yes, you read that right - 5 feet!) DLP screen, which among
> > other things,
> > has a direct VGA connection, so it could plug straight in to a PC
> > & function
> > as a monitor, as well as all the usual things. It also has a
touch
>screen
> > option, and a PIP option. This was advertised at £4995 (inc vat),
which
>I
> > reckon I could _JUST_ (with a little bribery) get Wife to
> > accept!! I don't
> > know how much the touch screen option would add to that cost, but
> > wouldn't
> > that be a COOL thing!! - a 5 foot wide touchscreen!!
>
>
>------------------------------------------------------------------------
>Was the salesman clueless?
>Productopia has the answers.
>http://clickhere.egroups.com/click/555
>
>
>
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