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Discussion Starter · #1 ·
Well im having a little trouble comprehending a few things. ok lets start simple:


film is 23.97fps, video is 29.97fps, say 24fps and 30 fps. to go from 30fps to 24fps you need to do a 3:2 pull down. then you can use 48 and 72hz refresh rates and not have any jitter. Now this is all fine and dandy for 480i dvd stuff. Does 1080i and 720p source material do this too? do i need to run my 60hz 720p signal at 48/72hz for movies? does my 30hz 1080i signal need to be run at 36hz?



now for my resolution troubles. dvd, 720/480 2x of that is 1440 by 960. Easy enough for 4/3 material or letter boxed stuff. But when you stretch out a 480 anamorphic dvd it turns into 854/480, 2x of that is 1712 or 1696 (divisible by 16). This creates problems for my wee little brain. Lets say you have a 4/3 set and are playing an anamorphic dvd. It will look too tall. using this logic on a crt with a anamorphic transfer, i should just be able to sqeeze the vertical to a 16:9 mode and it should look perfect, correct? using the 1440/960 mode. Of course non anamorphic stuff will look crushed. Or am i sopost to shoot for 1712 by 960 for a 16:9 setup for a 16:9 crt setup? this would give me a 16:9 desktop too.



Do you see my problem? Im setting up custom timings for my crt, but i only have 100mhz of bandwith. Thats not enough for 1712/960 48hz, but is enough for 1440/960 48hz. I also dont know if i should run my 720p rez at 60hz or 72hz, or my 1080i rez at 30hs or 36hz.



Does anybody have some preset timings im sopost to use?
 

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Let's start by the begining.


What is your projector ?


Then we will be able to give you the most accurate setting for it.
 

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Discussion Starter · #3 ·
nec 9200, 100mhz bandwith.
 

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I don't have time to get all the way into the weeds on everything, but I can comment on the anamorphic DVD thing.


Whether you're going to use 1440x960 or 1712/1696x960 just depends on whether you want to run square pixels or not. 1440x960 is a perfect 2x in both dimensions, so scaling is good - but the pixels won't be square after you squeeze to 16:9. As you mentioned, the picture will be distorted on everything but anamorphic DVDs. But...non-anamorphic discs can be aspect-corrected in software though, so that isn't necessarily a problem. What is a problem is if you want to use your HTPC for other stuff without changing resolutions - WindowsMedia, MPEG, web, etc. Unless the other software can correct the aspect ratio (hardly anything would), then things will be distorted as you figured.


SC
 

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Discussion Starter · #5 ·
I no problem changing rezolutions(sp). I was planing on a 720p desktop anyway. My problem was the refresh rates. Im not sure if i should use a 72hz or 60hz refresh on 720p, or a 30hz 36hz refresh on 1080i.


So far ive come up with this. Projectors basicly need zero portches(sp), i can do power strip pretty easy by now.


SO i got some resolutions so far. 1440/960 48hz squeese for anamorphic dvds thats about 100mhz. 720p 72hz is about 100mhz, and so is 1080i 36hz. Im not sure if i can make power strip settings for the same rez, but differnt refresh rates, ive always had a problem with that, and most of the time it doesnt switch.
 

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First of all film is not 23.97fps it is 24fps.

Second a 720x480 anamorphic DVD does not become 854x480 as you suggest.
 

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Discussion Starter · #7 ·
Quote:
Originally Posted by htpcfan
First of all film is not 23.97fps it is 24fps.

Second a 720x480 anamorphic DVD does not become 854x480 as you suggest.


Then what does it become? dlp projectors like the h31 have 854/480 panels to perfectly fit widescreen dvds. A 720/480 anamorphic dvd has to be stretched to something in order to look right. 854/480 is 16:9 so it should look right on a display that doesnt stretch pixels, like a 16:9 1280/720 pc desktop or digital projector.
 

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Quote:
Originally Posted by Nightanole
Then what does it become? dlp projectors like the h31 have 854/480 panels to perfectly fit widescreen dvds. A 720/480 anamorphic dvd has to be stretched to something in order to look right. 854/480 is 16:9 so it should look right on a display that doesnt stretch pixels, like a 16:9 1280/720 pc desktop or digital projector.
What do you mean what does it become? :confused:

The 720x480 pixel grid is mapped onto the 854x480 grid by the scaler.

Think about it? How can you possible make 854 out of 720 without scaling?


It appears like you have been listening to a salesman who just wanted you to believe you can watch 1:1 pixel mapped anamorphic DVDs on such a device. :)
 

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Discussion Starter · #9 ·
Ok how does one watch an anamorphic dvd in the correct aspect ratio? pc's and fixed pixel displays aside, a crt simply stretches the 720 pixels out so it makes a 16:9 image. its not 854 pixels, its 720 pixels stretched out. I got that part.


But what about pcs, how do pcs make the anamorphic transfer look right? A pc does not stretch its pixels. Lets say you have a 1280/720 desktop. If you just pop a raw 720/480 anamorphic dvd in it, it will look stretched out, like when you watch a dvdplayer in 16:9 mode connected to a 4:3 tv set. I assume the pc software stretches out the image to fill 854/480 pixels?
 

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Quote:
Originally Posted by Nightanole
Ok how does one watch an anamorphic dvd in the correct aspect ratio? pc's and fixed pixel displays aside, a crt simply stretches the 720 pixels out so it makes a 16:9 image. its not 854 pixels, its 720 pixels stretched out. I got that part.
No you did not get it.


A CRT does NOT stretch the horizontal 720 pixels squeezes instead it squeezes the 480 vertical scanlines from a 4:3 to a 16:9 image format.


Ok, I try this one more time: FORGET 845, there is no 845 ever, never. :)


An anamorphic DVD is a DVD that has the 16:9 format expanded onto a 4:3 format, in other words the picture is stretched vertically on the DVD. The whole reason behind this is to get more resolution in the vertical direction, since now there are 480 lines of resolution for a smaller vertical area.


In the horizontal direction, NOTHING, is changed, so it was 720 to begin with and it will remain 720.
 

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CRTs don't need zero porches, but you can reduce them from standard values.


I use 1920 x 1080i at 71.928hz primarily and sometimes 1280 x 720p at 71.928hz (actually at 75hz for PAL, but that's inconsequential).


1280x720


1280,72,136,72,720,19,3,44,88192,272




1920x1080i


1920,56,128,112,1080,4,10,30,89666,286


I don't use a 60hz res, as I don't watch NTSC video. If you only watched DVD and wanted a 720p res, 1440x720 would be a better choice - cleaner scaling.
 

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Man, you're worrying about a bunch of sh!t that you DON'T need to be worrying about. Your projector is going to be maxed out (sweet spot) at around 1280x720 maybe 1440x960 (mine is set at 60hz) so that is where you set your desktop and then simply load some players/codecs and ENJOY the picture. Personally I use a 6600GT with ZP, nvidia codecs, FFDshow with very little denoise/sharpen. Works GREAT. DON'T stress over the small stuff. You'll NEVER see the difference with your projector. MAYBE on a big 9 incher you might. I used to tweak tweak tweak until I wrecked everything and had to start over. Not any more. I actually WATCH the MOVIE now and NOT the millimeter here and there of imperfect convergence.


I'm NOT trying to be a prick here, I'm just trying to get you to relax and ENJOY your projector.
 

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That sounds like good sound advice DPB. Can you tell me what ZP stands for? I read about a program about a month ago in the wee hours of the night that improved imaging significantly. Unfortunately, my computer was shutdown by another family member before I could bookmark the page and now I can't find it. It had several screen shots with before and after toggling including one of Yoda. If this sounds familiar to anyone, could you tell me what it was and hopefully provide a link?


Thank you,

Craigo
 

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You should use 1440x720 if you are using a 16:9 raster, or 1440x960 for a 4:3 raster. USe a multiple of 24hz, i.e. 48 or 72. 48hz is unbrearably flickery for me, so I use 72hz. You are correct as you stated above it's not exactly 72hz, it's a multiple of the 23.97 so it.s 71.91hz or whatever.


You will then setup the AR of your player, say TT or zoom player for non-anamorphic stuff so that it is displayed correctly. You can have several different settings for different AR material, for widescreen non-anamorphic, for 4:3, etc.


This is assuming you're watching mainly all film-based material. If for some reason you only watch TV shows on DVD or something, then you'd probably want to pick 60hz refresh for instance.

Quote:
But what about pcs, how do pcs make the anamorphic transfer look right? A pc does not stretch its pixels. Lets say you have a 1280/720 desktop. If you just pop a raw 720/480 anamorphic dvd in it, it will look stretched out, like when you watch a dvdplayer in 16:9 mode connected to a 4:3 tv set. I assume the pc software stretches out the image to fill 854/480 pixels?
You will set the PC resolution using the drivers or powerstrip to a manual resolution that you want. For instance, say you want a 16:9 raster, for a 16:9 screen and everything in that. You will choose 1440x720 as the PC resolution. Then you will reduce the V-size of your raster down to 16:9, and anamorphic DVD will keep the correct AR, scaled at a perfect 2x to 1440x720. non-anamorphic DVD you will set up a separate AR setting for that and it will look just fine as well.
 

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Discussion Starter · #16 ·
Um whats this 1440/720 rez thing? I get the 1440/960 rez, but 1440/720?


1440/960 with a ver collapse would be a 16:9 aspec for a anamorphic transfer. 1440 is 2x 720 for hor, but ver 720 is not 2x 480. 1440/720 is 2:1, if i collapse it the ratio gets even bigger, not the 16:9 1.78:1 ratio im aiming for. I guess if i compress the 1440 it would fit...
 

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I'm sorry I was confusing. 1440 was 2x the horizontal size, but 720 is 1.5x the vertical size which makes the scaling easier. 960lines is too much for an 8-inch machine to resolve in 16:9. 720in the 16:9 frame is a good target, and if you have 960 in 4:3 that makes for 720 in the 16:9 frame.
 

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Discussion Starter · #18 ·
UR KILLIN ME!!!


Ok im gona go lie down now, maybe ill die being crushed by my 125lb 8 incher :D
 
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