Who needs an HDTV?
Monty Solomon
TECH LAB
Who needs an HDTV?
By Hiawatha Bray | May 8, 2008
Given the feeble state of the economy, many of you are in no mood to
blow $1,000 or more on a high-definition TV set. But then, you
probably own one already.
It's called a computer monitor. The typical monitor can display HD
video of respectable quality - not up there with a true HDTV set, but
not bad. All you need now is a fairly robust personal computer, and a
digital TV tuner that plugs into a USB port and captures the video
signals.
We've been trying out a couple of these tuners - the $99 Hauppauge
WinTV-HVR-950Q from Hauppauge Computer Works Inc. and the $129 PCTV
HD Ultimate Stick from Pinnacle Systems, a division of Avid
Technology Inc. in Tewksbury. These are list prices, by the way; shop
around and you'll likely find them for less.
Each gadget comes with a simple antenna that'll capture both analog
and digital TV signals being broadcast over the airwaves. Both
devices are made for computers running Microsoft Corp.'s Windows
operating system. But Hauppauge and Pinnacle offer similar tuners for
Apple Inc.'s Macintosh machines.
...
http://www.boston.com/business/technology/articles/2008/05/08/who_needs_an_hdtv/
Sam Spade
> TECH LAB
> Who needs an HDTV?
>
> By Hiawatha Bray | May 8, 2008
>
> Given the feeble state of the economy, many of you are in no mood to
> blow $1,000 or more on a high-definition TV set. But then, you
> probably own one already.
>
> It's called a computer monitor. The typical monitor can display HD
> video of respectable quality - not up there with a true HDTV set, but
> not bad. All you need now is a fairly robust personal computer, and a
> digital TV tuner that plugs into a USB port and captures the video
> signals.
Won't come close to a good HDTV with high-speed video processing,
conversion to 24 fps for Blueray DVDs, and on and on.
Plus, until you get to around 40 inches, much of it's lost anyway.
***** Moderator's Note *****
_What_ is lost below 40 inches, and why?
Bill Horne
Temporary Moderator
(Please put [Telecom] at the end of your subject line,
or I may never see your post! Thanks!)
T
So true, I've got my laptop set at the highest native resolution
1280x800
So it can do 720P no problem.
Scott Dorsey
>So true, I've got my laptop set at the highest native resolution
>1280x800
>
>So it can do 720P no problem.
Unfortunately, scaling up from the lower resolution to the higher resolution
isn't very good. With multisync CRTs, it was possible to change the resolution
of the video monitor to whatever the computer wanted it to be, but in the
flat panel monitor world, you pretty much have to operate the monitor at the
native resolution. If you set your computer for a different resolution than
the monitor, the monitor will have to rescale the video and the end result is
much poorer
Consequently if you want to display 720p, you need a monitor with 720 pixels
across it, or an even multiple of 720. Anything else and you are losing
resolution in the scaling process. The alternative, of course, is to mask it
down and live with a smaller image size.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
T
I thought the 720 was lines of resolution, not pixels across. If that's
the case I've got better than 1080.
I know the aspect ratio on SDTV is 4:3, and on HD it' 16:9, so by that
math I'd need 723 lines of 1280 pixels, and my display is set at
1280x800 so I'm a little bit over on the line count.
Anyone else have more info?
Linc Madison
<nospa...@cox.nospam.net> wrote:
> that math I'd need 720 lines of 1280 pixels, and my display is set at
> 1280x800 so I'm a little bit over on the line count.
>
> Anyone else have more info?
Yes, the 720 and 1080 numbers are the vertical, not horizontal.
720 = 720 v / 1280 h (monitors commonly 768 x 1366 or thereabouts)
1080 = 1080 v / 1920 h
My computer monitor is 1200 x 1920, so it can display 1080 images with
just a bit of letterboxing. Given how crash-prone my computer is,
though, I prefer to keep the TV separate.
--
Linc Madison * San Francisco, California * Telecom at Linc Mad d0t c0m
URL: < http://www.lincmad.com > * North American Area Codes & Splits
Read my political blog, "The Third Path" <http://LincMad.blogspot.com>
US, California, and Washington State laws apply to LINCMAD.COM e-mail.
Robert Bonomi
T <nospa...@cox.nospam.net> wrote:
>In article <g06q6s$jkt$1...@panix2.panix.com>, klu...@panix.com says...
>> T <nospa...@cox.nospam.net> wrote:
>> >So true, I've got my laptop set at the highest native resolution
>> >1280x800
>> >
>> >So it can do 720P no problem.
>>
>> Unfortunately, scaling up from the lower resolution to the higher resolution
>> isn't very good. With multisync CRTs, it was possible to change the
>resolution
>> of the video monitor to whatever the computer wanted it to be, but in the
>> flat panel monitor world, you pretty much have to operate the monitor at the
>> native resolution. If you set your computer for a different resolution than
>> the monitor, the monitor will have to rescale the video and the end result is
>> much poorer
>>
>> Consequently if you want to display 720p, you need a monitor with 720 pixels
>> across it, or an even multiple of 720. Anything else and you are losing
>> resolution in the scaling process. The alternative, of course, is to mask it
>> down and live with a smaller image size.
>> --scott
>>
>
>I thought the 720 was lines of resolution, not pixels across. If that's
>the case I've got better than 1080.
'lines of resolution' on one axis is _exactly_ the same as 'pixels' on the
other axis, when talking about a fixed-pixel based display.
Stack a number of rows (columns) of pixels side by side, with every other
one on/off, and you'll see the lines form in the other direction.
720 horizontal 'lines of resolution' means the same as 720 pixels vertically.
>
>I know the aspect ratio on SDTV is 4:3, and on HD it' 16:9, so by that
>math I'd need 723 lines of 1280 pixels, and my display is set at
>1280x800 so I'm a little bit over on the line count.
the math is 720x1280, not 723. <grin>
on a 800x1280 display, the display software typically leaves the top and
bottom 40 pixels black, allowing an exact 1:1 pixel mapping. Some stuff
will replicate every 9th row -- a 10/9 vertical 'stretch' -- which gives
a 'full screen' image at the cost of a bit of distortion.
T
lin...@suespammers.org says...
[Moderator Snip]
>
> Yes, the 720 and 1080 numbers are the vertical, not horizontal.
>
> 720 = 720 v / 1280 h (monitors commonly 768 x 1366 or thereabouts)
> 1080 = 1080 v / 1920 h
>
> My computer monitor is 1200 x 1920, so it can display 1080 images with
> just a bit of letterboxing. Given how crash-prone my computer is,
> though, I prefer to keep the TV separate.
>
>
Thanks for confirming that it's vertical resolution. So in essence I'll
get a bit of letterboxing on this laptop. No biggie. I much prefer net
based vids and haven't had many crashing issues.
Scott Dorsey
>
>I thought the 720 was lines of resolution, not pixels across. If that's
>the case I've got better than 1080.
Right, it's pixels top to bottom, which is the same as what video guys call
'vertical lines of resolution.'
It doesn't MATTER that you have more than 1080... it only matters that you
have 720 or an integral multiple of 720. If you scale the image up by a
non-integral size factor, you lose quality.
>I know the aspect ratio on SDTV is 4:3, and on HD it' 16:9, so by that
>math I'd need 723 lines of 1280 pixels, and my display is set at
>1280x800 so I'm a little bit over on the line count.
Right, so in that case you could just add some black borders and crop it down
a touch rather than scaling.
Robert Bonomi
Scott Dorsey <klu...@panix.com> wrote:
>T <nospa...@cox.nospam.net> wrote:
>>
>>I thought the 720 was lines of resolution, not pixels across. If that's
>>the case I've got better than 1080.
>
>Right, it's pixels top to bottom, which is the same as what video guys call
>'vertical lines of resolution.'
WRONG!!! 'pixels top-to-bottom", is the same as what the video guys call
"*HORIZONTAL* lines of resolution".
Its _easy_ to get confused. But remember if you light up the same pixel
position in adjacent _vertical_ columns, this draws a =horizontal= line.
to wit:
..........
..........
..........
OOOOOOOOOO
..........
..........
..........
..........
..........
>It doesn't MATTER that you have more than 1080... it only matters that you
>have 720 or an integral multiple of 720. If you scale the image up by a
>non-integral size factor, you lose quality.
Subject to how you define 'quality', that is. If the scaling is in a non-
integral _rational_ ratio that can be expressed using integer values that
are close to each other, one can simply replicate selected scan lines with
very little "observable" impact.
AND, if you employ more advanced image-processing techniques -- e.g., things
like 'edge detection' -- you can actually end up with a scaled-up image that
appears 'sharper' than the "original". There will, in all likelihood, be some
differences from 'reality' (i.e., in comparison with the same image at a
native resolution equal to the scaled-up size) -- the techniques involved
do introduce possible 'artifacts' in the image sharpening process.
Those quibbles aside, _simple_ (linear interpolation) scaling does result
in some degradation of image quality _IF_ the scale factor is non-integral.