[mythtv-users] OT: HDTV TV's

Marco Nelissen marcone at xs4all.nl
Thu May 11 21:52:12 EDT 2006


>On 05/11/2006 12:19 PM, Mike Frisch wrote:
>> On Thu, May 11, 2006 at 11:58:19AM -0400, Michael T. Dean wrote:
>>   
>>> Exactly.  And, technically, a 1920x1080 (1080p) display cannot fully 
>>> resolve a 1920x1080 input signal (whether 1080i or 1080p).  As a matter 
>>> of fact, a 1920x1080 (1080p) display cannot even fully resolve a 
>>> 1280x720 input signal (i.e. 720p).
>>>     
>> I'm not following you here...  By "resolve", I mean that all 1920x1080
>> pixels are represented as a distiguishable, albeit very small, and
>> individually addressable point of light.  Is your definition of
>> "resolve" different than that?
>
>Basically, I'm saying there's more information available in the input 
>signal than can be represented by an output device using a 1:1 pixel 
>mapping.
>
>To get an idea of what I mean, play back a 720x480 anamorphic 
>widescreen, commercial DVD on a 4:3 CRT that's set to use 640x480 (i.e. 
>with Xrandr/Ctrl-Alt-"Numpad +"/Ctrl-Alt-"Numpad -") and have the player 
>cut off the left and right (i.e. to get a 1:1 pixel mapping--a 4:3 DVD 
>(whether a 4:3 show or letterboxed widescreen) uses non-square pixels, 
>but your display doesn't, so you'd get scaling).  Then, change the CRT 
>to 1280x960 and do the same.  The image is significantly better looking 
>at 1280x960 even though the pixels are "resolved" (by your definition) 
>at 640x480.

I think you'll find that this experiment will not give the results you
describe on LCDs and plasmas. It only happens on CRTs because of the
way CRTs work, and has nothing to do with there being more information
in the input signal than the display can show. Simply put, the black
lines between the scanlines will be bigger for lower resolutions, which
makes the image appear to be of lesser quality.


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