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Discussion Starter · #1 ·
I have read on the forum "tidbits" about 1:1 pixel mapping between an HTPC and the 4805. To some, this is the holy grail for us entry level home theater projector people. Here are my newbie questions.

#1 What is 1:1 pixel mapping?

#2 Why do it?

#3 What are the advantages?

#4 How does one start setting up the mapping process?


I currently have a Denon DVD player and DirecTV sat going through component to the 4805. I also have an Athlon 3200, 1 Gb ram, Nvidia FX5700LE, 1.2 TB HTPC running through the DVI port to the 4805. As far as I can tell Windows XP and the Nvidia detected the 4805, set the display resolution and my screen (84 X 47.75) is filled. With a few tweaks to the software and the projector I have a beautiful picture. But I can't leave well enough alone! Give me a few clues and I will be off and running. In particular, I have seen DaGamePimp and Luis talking about this. As usual, thanks in advance for any and all information and help.


Chuck
http://www.cwitt.com/htpc_title.htm
 

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Heres what worked for me:


Download and install the latest Nvidia drivers. Connect the 4805 to your video cards DVI output via an "M1 to DVI-D" cable. Set the projector to "Native" video mode.


Set the PC's resolution to 848x480. Find the advanced setting that allows you to select from options; "fixed display/center scaled/adapter scaled/monitor scaled" (or something to that effect) and select the "monitor scaled" option.


This is assuming youre using just the 4805 with no other display device.


If youre using a second monitor try the "Dual Display" mode. (you may need to restart before this option becomes available) This will allow you to set the resolutions for each device independently.


Under the computers display settings, youll see the pictures of the two monitors and by right clicking on them, you can set the properties independently. Do not select the option "Treat device as HDTV" This restricts the choice of resolutions.


Of note, there is the ability to set the full screen option to Auto or Disabled and the ability select which monitor is "Primary" These settings can help you to tailor a prefered method of playing movies.


I set my 4805 to be the Primary, and I disable full screen on my PC monitor. This works best for me, YMMV.


The options I mentioned take a bit of clicking to find, but it shouldnt be too tricky.


A word on the cable. I spent around 30 bucks on a 25 foot cable. Shop around. Be sure to get the "digital only" version. DVI can also carry an analog signal. To avoid doubt as to whether the signal is actually digital or analog, get the DVI-D cable. The "-D" denoting "digital"


Heres a bit more on 1:1 pixel mapping:
http://archive.avsforum.com/avs-vb/s...threadid=90884


Use the desktop pattern as instructed to verify that you are indeed mapped correctly. If you have problems, you can also try the 640x480 resolution as it also seems to do 1:1 But its not ideal for movies, and I only recommend using it for troubleshooting. If youre still having trouble you might also try completely disconnecting your computers monitor so that only the 4805 is connected and then restart everything. Also try the auto-adjust on the remote at various stages.


Im using an Nvidia 5700 video card.


Good Luck!



-Ric



EDIT:


!!!! Be sure you set keystone to zero, otherwise youll never get 1:1 !!!!
 

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The perfect 1:1 will actually be 854x480 not 848x480. Thats what we in the 4805 thread are trying to acomplish but it doesnt seem too easy. I got something going but we still dont know if its true 854 or not. I am doing tests to find out.

Regards
 

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Discussion Starter · #5 ·
Quote:
Originally Posted by dgrambo
Heres what worked for me:


Download and install the latest Nvidia drivers. Connect the 4805 to your video cards DVI output via an "M1 to DVI-D" cable. Set the projector to "Native" video mode.


>>See #1 below


Set the PC's resolution to 848x480. Find the advanced setting that allows you to select from options; "fixed display/center scaled/adapter scaled/monitor scaled" (or something to that effect) and select the "monitor scaled" option.


>>See #2 below


This is assuming youre using just the 4805 with no other display device.


>>See #3 below


If youre using a second monitor try the "Dual Display" mode. (you may need to restart before this option becomes available) This will allow you to set the resolutions for each device independently.


Under the computers display settings, youll see the pictures of the two monitors and by right clicking on them, you can set the properties independently. Do not select the option "Treat device as HDTV" This restricts the choice of resolutions.


Of note, there is the ability to set the full screen option to Auto or Disabled and the ability select which monitor is "Primary" These settings can help you to tailor a prefered method of playing movies.


I set my 4805 to be the Primary, and I disable full screen on my PC monitor. This works best for me, YMMV.


The options I mentioned take a bit of clicking to find, but it shouldnt be too tricky.


A word on the cable. I spent around 30 bucks on a 25 foot cable. Shop around. Be sure to get the "digital only" version. DVI can also carry an analog signal. To avoid doubt as to whether the signal is actually digital or analog, get the DVI-D cable. The "-D" denoting "digital"


Heres a bit more on 1:1 pixel mapping:
http://archive.avsforum.com/avs-vb/s...threadid=90884


Use the desktop pattern as instructed to verify that you are indeed mapped correctly. If you have problems, you can also try the 640x480 resolution as it also seems to do 1:1 But its not ideal for movies, and I only recommend using it for troubleshooting. If youre still having trouble you might also try completely disconnecting your computers monitor so that only the 4805 is connected and then restart everything. Also try the auto-adjust on the remote at various stages.


Im using an Nvidia 5700 video card.


Good Luck!



-Ric
#1 Have latest drivers. Have Infocus 10 meter DVI to M1 cable. PROJECTOR WAS NOT SET TO NATIVE MODE!


#2 This was already set this way.


#3 There is no other display device.


Thanks for the advice. I am using the test pattern you linked to and it did clear up when I switched the 4805 to native mode. Another tweak in my quest to get all I can from my 4805!


Chuck
 

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Discussion Starter · #6 ·
Quote:
Originally Posted by Luis Gabriel Gerena
The perfect 1:1 will actually be 854x480 not 848x480. Thats what we in the 4805 thread are trying to acomplish but it doesnt seem too easy. I got something going but we still dont know if its true 854 or not. I am doing tests to find out.

Regards


Luis:

Why 854 and not 848? What got me started on this was your thread about using ffdshow and theatertek, etc.


What are the advantages of 1:1 mapping?


Chuck
 

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Quote:
Originally Posted by chasw98
Luis:

Why 854 and not 848? What got me started on this was your thread about using ffdshow and theatertek, etc.


What are the advantages of 1:1 mapping?


Chuck
chasw98,


I am not an expert, but I believe the reason is 854:480 is closer to 16:9 than 848:480 in ratio. Also, I don't think you can have an odd resolution, and hence 853 is not an option.


1:1 mapping means that there will be no scaling. Don't hold me against this, but I would think that any scaling will affect the output. Usually you have more pixels than the actual data, you will predict what the missing data should be. This can introduce artifacts. On the other hand if you have to few pixels, you might average (or some sort of algorithm) to combine those pixels into one. Thus, again possibly causing artifacts...


Hope that helps.
 

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Actually 854x480 is the 4805's resolution thus mapping 1:1 to 854x480 should deliver the best image quality but it is hard if even possible to do with current video cards. Basically most video card work based on 8s ie 106x8 = 848 . As far as I know the Nvidia is able to work per pixel thru DVI so it maybe possible as I am testing now, to achieve the perfect 1:1. Still can prove it though.

Regards
 
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