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Anyone achieve 1:1 pixel mapping with no overscan with nVidia card and sammy dlp  

post #1 of 9
Thread Starter 
I just purchased the 6600 gt with dual dvi a few days ago to replace my 9800 pro a-i-w. 6600 gt is a better gaming card and I figured I could hook one dvi into my sammy hln series dlp and the other into my monitor, so watch movies or play games on tv and still use comp. I am using the the new 66.93 drivers, I think they are the only ones with support for 6600 gt.

The card recognizes the tv as a samsung dlp and even knows to set the resolution to 1280x720 at 60 Hz, which was pretty cool. I get 1:1 pixel mapping but with overscan, TV(Wide) mode. When I set the res to 1248x702 the tv just stretches the image. I know many people with sammy dlp's have had the problem where they can't get "normal" aspect ratio for dvi unless they use custom timings. I don't know why that happens, but that was the only way I could get 1:1 pixel mapping with my ati card. However the nvidia doesn't allow me to use custom timings for the sammy.

The only way I was able to achieve 1:1 pixel mapping with no overscan is when I set custom timings at the res 1248x702 for my comp monitor(primary display) and set the comp monitor to those specs. Somehow the tv (secondary display) accepted those settings and it looked great and overscan was gone.

However there were 2 problems with this
1. It required me to keep my 4:3 computer monitor at 1248x702 60Hz which looks terrible.
2. If I try to start a game (Half Life 2) it opens on the primary display. And if I if I make the sammy the primary display the overscan comes back.

If anyone has had any success with a similar setup or has any ideas please let me know. I might just return the card and go back to ati if I can't get rid of the overscan.

If anyone takes the time to read this long winded incoherent message, thanks for your time.
post #2 of 9
In order to eliminate the overscan you need to set the Sammy to PC-wide instead of TV-wide and be sure you are sending 720p (1280x720@60Hz).
post #3 of 9
Thread Starter 
PC Wide leaves large black bars on all sides of the screen. Plus the picture is all fuzzy and text difficult to read because it's not 1:1 pixel mapping. I was able to get 1:1 pixel mapping and no overscan with the ati card in "normal" mode.
post #4 of 9
1:1 pixel mapping is only a goal if you believe that the ability of your source to scale to the native resolution of your TV/monitor is better than the ability of your TV/M monitor to scale to its native resolution from a source of a different resolution/ frequency. Today most of the HDTVS have much better scaling software built in than do to the video cards or STBs so 1:1 pixel mapping will cause worse PQ than sending the video at what it was created by the video camera and letting the TV do the scaling.
With what video are you getting black bars on the side at 720p? If it is from a network digital broadcast of a SD program the network inserts the black bars as part of the video itself when it upscales the program from 480i to 720p or 1080i.
post #5 of 9
canesrule, how did you achive 1:1 pixel through DVI with your ATI card? I tried 1248x702 with my ATI 9700 through DVI but it doesn't get rid of overscan completely nor does it have 1:1 pixel even though my Samsung is in "expand" mode. Thanks.
post #6 of 9
Thread Starter 
I used these timings I got from someone's post.
If you use these params in powerstrip the Samsung will let you change the aspect ratio to "normal" this should get you 1:1 with no overscan.

PowerStrip timing parameters:
1248x702=1248,64,128,176,702,1,3,21,70500,2304

Generic timing details for 1248x702:
HFP=64 HSW=128 HBP=176 kHz=44 VFP=1 VSW=3 VBP=21 Hz=60

Linux modeline parameters:
"1248x702" 70.500 1248 1312 1440 1616 702 703 706 727 +hsync +vsync

http://www.avsforum.com/avs-vb/showt...283340&perpage
=20&pagenumber=11
http://www.avsforum.com/avs-vb/showt...72388#post2872
388
post #7 of 9
Thanks for the info!

I still have slight overscan but much better then what I had before. I had to use 1240x700 to get it to this point (<2% overscan). Going lower then that didn't help and only produced underscan. Also had to use the service menu to center the image. I have a HLP, maybe the HD3 chip can't do 1:1 pixel without overscan. Oh well, I'm very happy with the current results, Thank you very much!
post #8 of 9
I was under the impression that tv-wide, and pc-wide modes both re-scaled the image, and that 'expand' was the no overscan mode if feeding 1280x720? And even with 1:1 pixel mapping you would still have overscan as the overscan existed in the optics?

-pd
post #9 of 9
Thread Starter 
TV-Wide will scale everything to 1280x720 but only 1248x702 pixels are actually displayed, so if you give it a 1280x720 source you get 1:1 pixel mapping but it only displays 1248x702 of those pixels. In "normal" mode it doesn't scale anything if you give it a 640x480 image it displays 640x480 pixels. So in "normal" mode if given 1248x702 source it has 1:1 and no overscan. Problem is the only way I can get the option of "normal" aspect ratio option for the DVI input is with custom timings
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