AVS Forum banner

Status
Not open for further replies.
1 - 4 of 4 Posts

·
Moderator
Joined
·
23,030 Posts
A DVD player (or some other video output device) sending your digital display the resolution that matches the digital display's "native resolution". eg. If your plasma is 1280x768 and you send it 1280x768 video you are doing "1:1 pixel mapping". The common one is a DVD player or cable stb sending 720p to a 1280x720 (720p) DLP TV or PJ. Many DLP chips are 1280x720 native resolution. Any other display requires a DVD player with custom settings, an external scaler or HTPC to generate the appropriate resolution for 1:1 mapping. Well, there's a couple players with 1080p and a couple displays that accept it. When you feed a display something other than its native resolution the scaler in the display scales the input to match the native resolution.


larry
 

·
Registered
Joined
·
42 Posts
Quote:
Originally Posted by PooperScooper
A DVD player (or some other video output device) sending your digital display the resolution that matches the digital display's "native resolution". eg. If your plasma is 1280x768 and you send it 1280x768 video you are doing "1:1 pixel mapping". The common one is a DVD player or cable stb sending 720p to a 1280x720 (720p) DLP TV or PJ. Many DLP chips are 1280x720 native resolution. Any other display requires a DVD player with custom settings, an external scaler or HTPC to generate the appropriate resolution for 1:1 mapping. Well, there's a couple players with 1080p and a couple displays that accept it. When you feed a display something other than its native resolution the scaler in the display scales the input to match the native resolution.


larry
muchas gracias :)
 

·
Registered
Joined
·
8,770 Posts
Quote:
Originally Posted by PooperScooper
If your plasma is 1280x768 and you send it 1280x768 video you are doing "1:1 pixel mapping".


larry
Not necessarily.


There are many display devices- LCD panels, plasmas, LCD and DLP projectors- that will not 1:1 pixel map even if you feed the display it's native resolution!


Many display devices will over-scale even its native resolution in order to overscan the display borders.


To verify if you are really 1:1 mapping, you need to feed your display a 1 pixel pattern such as:

http://www.marky.com/files/hometheat...-and-phase.gif


and verify there is no noise, moire patterns, or periodic light/dark vertical bands in the tiled test pattern. Simply tile the test pattern on any Windows or Linux desktop, i.e. unscaled by the PC, then set the desktop resolution to the native res of your display at 60Hz.


One recent example that caused quite an uproar in the digital projectors forum is the Sony HS51 projector.


I have not read any HS51 threads for many months, but during Q4 2004 and Q1 2005, the HS51 could not 1:1 map 1280x720 input signals- the native resolution of its own panels!


Sony LCD projectors have been afflicted with this issue since the 10HT.


Likewise, many plasma and current LCD panels cannot 1:1 map their native resolution- they scale all input resolutions, including their native rate.


This is not good for those wanting to achieve the highest detail from their input signals, or those wanting to use high PC desktop resolutions at close viewing distances.


I researched 32" LCD panels for many months to find the Winbook 32" panel, which actually has an ascpect ratio setting called "One to One".


I would not buy a digital display device that could not 1:1 pixel map its native resolution, and preferably any resolution lower than its native. That's why I bought the AE700 projector and this Winbook 32" panel. Both are trivial to 1:1 map.


The principle here is to scale the video signal only once, since every scaling operation will degrade the video in some fashion, usually reducing detail and/or adding some form of noise to the video signal.



Remember:

Scale me once, shame on you, scale me twice, shame on me! :D


In a perfect world, we would have display devices that displayed all incoming signals at their native rate, whith the exception of perhaps 480i and 480p, which need deinterlacing to remove the Venetian blind efect for 480i, and scaling up to increase pixel count on large displays for 480p and deinterlaced 480i.
 
1 - 4 of 4 Posts
Status
Not open for further replies.
Top