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Discussion Starter · #1 ·
Can anybody tell me what the proper settings are for Powerstrip, at 1360x768, with a D-ILA powered by a GeForce video card?


I know just enough about this stuff to be dangerous, and am still unclear as to which of the numerous Powerstrip settings make a difference to get "pixel-perfect" playback. I've seen several different combinations of settings, all claiming to be ideal. I believe that the current consensus is to use 75.1 hz refresh, but am unclear as to whether or not the other settings even matter. For example, do the "porch" settings matter? What the heck is a "porch", anywhoo? I found that one set of Powerstrip settings seemed to cause the left edge of the image to be cut off, unless I compensated by changing the horizontal position with my D-ILA's remote.


On a related note, is it ok to reposition the image using the remote and/or the porch settings, to get it to line up with your screen? I think I've found that some porch settings can cause horizontal "ghosting", so I don't think that's a good way to position the image, although I've never seen this mentioned. How about using the projector's position controls?


- Dave
 

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Hi Dave,


Aren't you using the 3 preset DILA resolutions from within Pstrip? You don't really need to tweak too much if you start with these.


I posted this thread about a month ago of my findings on refresh rate Hz. I'm suprised not too many people commented on what I found. I figured Mark R would be all over me. http://www.avsforum.com/ubb/smile.gif


The difference is very dramatic for my GeForce based system driving the G11. I don't use 71.997 at all anymore.


Chris
 

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Dave,


I should've given the original post by Mark Rejhon here .


Chris
 

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Discussion Starter · #4 ·
Thanks, Chris!


Yes, I did see your earlier post, and had adjusted my refresh rate to approx. 75 hz. I think if I read through Mark's post you referenced, I could figure this out myself. However, as a point of reference, would you mind posting what your pstrip settings are, if you have that info handy? Also, do you know if moving the image around using the D-ILA's position controls affects anything?


(an irrelevant aside - I just went out on my patio for a minute while a movie was playing, and was shocked to see my first impression of the dreaded screen door effect with my projector, when I watched the movie from my patio. Then, I realized that I was looking at the screen through a screen door! Watching the screen through a screen door really is an excellent way to simulate "the screen door effect." No joke, that had me going for a minute. Doh!)


- Dave
 

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Chris,


Thanks for posting the link to your interesting powerstrip adjustments. Six months ago I spent time doing something very similar, but never really looked for improvements in the picture - it didn't make sense to me how it could be better and I just assumed that it had to be where the 'perfect' settings were to be perfect.


After adjusting the settings for the last hour, I can honestly say that my image has improved. I saved a couple different powerstrip display changes and switched between them - it was a clearly noticable difference, though I don't understand how.


I ended up using 1360x768 @ 75.763hz - it gave me the sharpest image near 75hz and was obviously clearer than when at 71hz.


Maybe someone can explain this to us... but thanks for giving us your idea to try it.


Brian


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Our Home Theater - http://www.fatbulldog.com

Last updated 6/1/01
 

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"(an irrelevant aside - I just went out on my patio for a minute while a movie was playing, and was shocked to see my first impression of the dreaded screen door effect with my projector, when I watched the movie from my patio. Then, I realized that I was looking at the screen through a screen door! Watching the screen through a screen door really is an excellent way to simulate "the screen door effect." No joke, that had me going for a minute. Doh!)"


That's funny; you had me going for he first four lines. http://www.avsforum.com/ubb/smile.gif


---------------------------

Pixel Clock 141.227


H. Geometry


Scan rate 77.427

Active 1360

Front Porch 104

Sync Width 144

Back Porch 216


Total 1824

------------------


Refresh Rate 73.044


Active 768

Front Porch 129

Sync Width 3

Back Porch 160


Total 1060

------------------------------


SXGA3 will sync very quickly with these settings. I think this may have been Todds problem that he posted about a month ago.


Moving the DILAs position controls will do nothing to affect Powerstrip, but changing the Pstrip settings may indeed put the image in a position that doesn't agree with your DILA.


Try to stay with the Pstrip presets or my settings(very close to the same)and you should be fine.



Chris

 

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Dave,


My G11 is currently table mounted, so my H Pos is at 33 and V Pos at -116.


I started out long ago with the Pstrip Pixel Perfect 1360 x 768 settings but since then have done Dilard mods to 1360 x 768 for SXGA3, so our comparisons may be a little different because of the changes I think I made with image start, position, etc. from within the Image Geometry Wizard. Still, our numbers should be pretty close with the exception of H Pos.


If you like, I can e-mail you my latest Dilard report. Mark implemented the ability to print/send a report with the latest Back Up Wizard, why not use it to the best of our advantage? http://www.avsforum.com/ubb/smile.gif


Chris



[This message has been edited by CCLAY (edited 07-01-2001).]
 

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Discussion Starter · #8 ·
Thanks for the offer, Chris!


I'm not sure if your settings would help me or not. It seems like there's two things you can do with these adjustments: move the image around, and "help" the projector synch with the video card's output, to get the best picture. All I'm interested in is the latter - I'd prefer to move the image by physically adjusting the projector. However, it would be nice to be able to use the position controls to move the image, too. I still don't understand if that interferes with what Powerstrip settings you use, or not - that's one of my questions.


It does seem like the image geometry settings go hand in hand with what Powerstrip outputs, but it also seems like the "ideal" settings would be done to work with an h-pos and v-pos of zero...


- Dave
 

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Brian,


I can't explain it either, but it is a reality.


Interestingly, I notice that using my 73.044 refresh shows a bit fuzzy when I first turn on my G11, but after 10 or 15 minutes, it's crystal clear. Who said DILAs don't have to warm up.......crap, I think it was me. http://www.avsforum.com/ubb/smile.gif


Dave, FWIW my exact settings are V Pos -116, H Pos 33. I was at work when I posted earlier and got the two mixed up. Sorry. I'll edit it.


I'm confused as to what it is you're exactly trying to do. Do you have a sync problem? Changing the DILAs position settings will have no effect.


The position(through DILA) controls will have no effect on anything in Pstrip. Dilard will have no effect on Pstrip. You can, however, make changes in Pstrip that move the image around, make changes in Dilard that move the image around and of course H and V Pos through the Pj itself.


Again, I leave Pstrip alone except for refresh rate, and use Dilard and G11 controls for image position.


Refesh rate does indeed have an affect on a good sync.


Chris
 

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Discussion Starter · #10 ·
Chris:


I'm trying to get Powerstrip settings that work with the h-pos and v-pos on the D-ILA at 0, 0. With your settings, and with my unmodified sxga3 settings in the projector, the image was cropped on the left side. I could move the h-pos to the right, so that it was no longer cropped, however. It seems to me that the "cleanest" powerstrip settings would work with h-pos and v-pos at 0, 0. So, it's not quite true that Powerstrip and the position settings don't interact, but perhaps it doesn't really matter if you need to adjust the position with certain powerstrip settings. Also, it also seems like you can adjust things in the image geometry wizard such that certain powerstrip settings work for you, but wouldn't be ideal with unmodified sxga3 settings, no?


I still haven't read through all of the Mark Rejhon post that you posted the link to. Perhaps after I digest that, all will become clear...


- Dave
 

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Chris,


My D-ILA takes about a half hour to warm up as well. When I first turn it on, my current phase setting looks fine. But, after a few minutes it drifts and I have to continue to adjust it for about a half hour. Or I just ignore it and all is well after the warm up.


Kind of strange, but they definitely need to be warmed up.


Also, have you thought much about the refresh rate and its affect on added stutter relating to motion from film. I'm not sure, but it would seem that 72hz would be more appropriate given that it is a multiple of 24. Do you know if this has any affect? I tried watching for added stutter tonight after using the new settings and it does seem more pronounced, but I'm always watching for stupid little details and it sure isn't a scientific study...


Brian


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Last updated 6/1/01
 

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Discussion Starter · #12 ·
Thanks, Chris.


I tried your settings, and I needed to change the front porch to 72, and ack porch to 248. Otherwise, the left side of the screen was cut off, unless I moved the image with the projector's position controls. Is this not what you see? Do you have your H. Pos. set to 0?


- Dave
 

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"I'm trying to get Powerstrip settings that work with the h-pos and v-pos on the D-ILA at 0, 0."


I tried that a couple months ago but didn't have any luck. I was using Dilard though, not Pstrip. Forcing numbers too much in Pstrip will give you a useless, garbled screen, forcing you to do a hard reboot. I prefer not to do that as I lose my vid card drivers when that happens. In Dilard, hitting Esc twice will kill the change that gets you into trouble. I have an advantage though as I use a twin view card, so any major tweak too far doesn't show up on the 2nd monitor, just the G11. Very handy.


"It seems to me that the "cleanest" powerstrip settings would work with h-pos and v-pos at 0, 0."


Negative. Pstrip tweakings have nothing to do with H & V position on the DILA from a direct interactive standpoint. True, changing front and back porch in Pstrip may force you to have to change H or V Pos on the DILA to get the image proper on your screen, but that's obviously expected. Porch, H and V will do nothing to give you a "cleaner" picture. Tracking, phase, focus, refresh rate, etc. will.


A good way to look at this is that you really have 3 ways to set position; Pstrip, Dilard and the DILA itself. Changing one doesn't change the numbers of the other two, but it may change where you'll have to set them for your image to be correct, or back to where you started(in position).


Have you tried to position things using Dilard? I'd use Dilard rather than Pstrip, FWIW.


Quote by Brian:

"have you thought much about the refresh rate and its affect on added stutter relating to motion from film. I'm not sure, but it would seem that 72hz would be more appropriate given that it is a multiple of 24. Do you know if this has any affect?"


Ironically, just tonight I did some comparisons between 60 and 75 hz(GF MX2, PIII800, CUSL2 mobo, 128 ram), and all points between. I was using PDVD3 and WDVD3. Contrary to what I've read here many times, I saw no difference in stutter between 60 and 75 on either player. I did, however, notice that WDVD3 was slightly better with stutter than PDVD.


Ya wanna here some real truth? I picked a few scenes from different discs that I know to have some stuttering and went back to my Toshiba DVD player via component connects and saw the very same stuttering. Same thing using Toshiba to RCA RPTV via S-Video. I did this many months ago as well, but just to confirm, I did it again. So maybe some of the things we see are in the disc to start with.


Chris


 

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I ran across these statements by Ashley of Powerstrip today while perusing about. Thought it might be helpful.


"The important thing to keep in mind is that behind the numbers, the only thing that is really adjusted is the pixel clock. The scan frequencies are just mathematically derived from the pixel clock and total number of pixels displayed. How the scan frequencies numbers you see on screen are presented - as whole integers or with so many decimal points - has really been determined by the programmer."


"Horizontal scan frequency = pixel clock / total # of horizontal pixels per scan line (including borders)


Vertical scan frequency (or refresh rate) = Horizontal scan frequency / total # of scan lines (including borders)"

 

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CCLAY,


Thanks for doing the tests from 60-75hz to see what you could determine. I ended up doing something very similar as well and couldn't notice anything.


Coincidentally, I also connected a stand alone dvd player and tested a few scenes as well and saw stutter in the same spots. I believe that the stutter simply comes from the translation of film to video, or the 3:2 pulldown and creates this annoying affect. I also think that it is just more pronounce for those of us displaying the picture so large and so clear - everything little imperfection stands out.


Brian


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Our Home Theater - http://www.fatbulldog.com

Last updated 6/1/01
 
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