[opendtv] Re: (No Date: Tue, 28 Sep 2004 10:30:37 -0400

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Wed, 20 Oct 2004 09:37:48 -0400

>At 6:03 PM -0400 10/19/04, Manfredi, Albert E wrote:
>But the actual aspect ratio is 1.25:1, and that
>is what images are scaled to, apparently.

So it would seem. Only one of the graphic modes you listed is 
"correct" for your display. All of the others would require the 
techniques I described in the previous message to prevent distortion 
of the computer output.

>
>>  LCD displays have ONLY one resolution. At least
>>  we can make a safe assumption that your screen
>>  has 1280 x 1024 pixels that are in fact square.
>
>Well, I haven't messed with every setting, but the
>only one that seems distortion free that I've
>tried is the highest setting, 1280 X 1024. And
>that's what the literature says it is "optimized"
>for. But I'm using 1152 X 864 at the moment.

So if the graphics card scales this  1.33 raster to fill the entire 
display, it is scaling the horizontal using a factor of 1.11 and the 
vertical by a factor of 1.185. This is the source of the distortion 
you are seeing. IF it used the same factor to scale both H&V you 
would see an active raster of 1280 x 960 with 64 lines that are not 
active.

>Point being that in the real world, these things
>are bound to happen. Whether or not your
>fictitious "properly designed" system would behave
>this way.


What is "fictitious" about a properly designed system? As I pointed 
out other manufacturers seem to deal with these issues "properly."


The point is that this is how the manufacturer of your system 
designed the system to deal with the accommodation of different 
rasters on a fixed resolution, fixed aspect ratio  LCD panel. This is 
no different that what a CE manufacturer must do to accommodate all 
of the formats that may be presented to an LCD DTV display. Most 
actually are more clever, offering additional modes to fill the 
screen when the source has a different aspect ratio. For example, 
some DTV display offer a nonlinear distortion of 4:3 to fill the 16:9 
screen; the central area of the screen is not distorted, but as you 
move closer to the edges of the picture the image is distorted more 
severely. The result is that objects moving to the edge of the screen 
appear to grow "fatter" as they leave the screen.

>
>Most people might not even have noticed, unless
>they actually did some graphics programming.
>That's when you see the ovals instead of circles.

True. Some people can accept the distortions of viewing 4:3 source 
when it is stretched to 16:9 to fill a TV display. The reality is 
that many forms of imagery are quite acceptable with limited 
distortion, while other applications are more demanding.

>In a real world looking at LCD TVs as the staple
>diet, or other true digital displays, it makes
>sense to limit the transmission options to
>something less than infinity. To me, this is just
>plain common sense, for someone trying to design
>a bullet proof DTV system.


Why?

We are never going back to only one aspect ratio. This simply is not 
going to happen. Likewise, we are not going to migrate to a single 
level of resolution. These are MAJOR limitations of the television 
system we are trying to replace. These limitations only exist in 
"legacy" electronic media. Try telling a cinematographer, or a 
photographer, or a graphics designer who produces magazines or 
newspapers that they can only use one aspect ratio. it never happened 
and it never will.

Why are you so resistant to the notion of providing the same 
flexibility for electronic media, even as you are staring at a 
digital media appliance that has been designed to provide this 
flexibility?

Regards
Craig
 
 
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at 
FreeLists.org 

- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.

Other related posts:

  1. Home
  2. opendtv
  3. Archive
  4. 10-2004