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Discussion Starter · #1 ·
OK,

I have a P3-933 system. What I want o know is what type of system is necessary to eliminate the studder when there is a scene pan? Will even the fastest processor/memory type combo make a difference?




Asus CUV4X, Radeon AIW, Win2k, 256(pc133), LT150 projector

(all drivers, bios, SPs, etc. updated)
 

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I don't know about Win2K (I use WinME), but the most important thing for me is using 60Hz refresh on my projector (but it's not an LT150). Of course, eliminating most other background processes and unchecking 3:2 pulldown (so that it is really enabled) in DVDGenie, goes without question. Your processor is definitely fast enough. Good luck.


Carey
 

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Yep, its the software rather than the hardware. You got power aplenty, just need a few tweaks here and there. I never fully solved the judder issue in WinDVD/Win2k (although I didn't try very hard!) - now I'm leaving all my tweaking and fine tuning for the TheatreTek player once it arrives in the hope that it has less of a judder problem (but being honest I think it will have just as much and its up to us to individually solve it).

Regards,

Paul
 

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Cary "Of course, eliminating most other background processes and unchecking 3:2 pulldown (so that it is really enabled) in DVDGenie, goes without question."


I thought leaving checked turned on 3:2 pulldown. Please explain.



Warren
 

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Depending on your display, using an even

multiple of 24hz (e.g.: 72hz) as your

VGA card refresh rate might help.


Just try the different options for VGA

card refresh rate and see if some work

better than others.


You are running with DMA enabled on your

DVD-ROM drive, right?
 

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Maybe this can help a little.


When I recently reinstalled win98SE on a separate partition, with no added junk, I tried ATI 4.1 player and noticed the picture was not going smoothly, as it used to do before the reinstall. The DMA was enabled by default (with Intel Ultra ATA Driver), so what was the problem?


Then I realised that I forgot to reinstall DX 8.0. I ran the installation file and the playback was much better. With TT player it is even better still.


Leszek.
 

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loganross,


If you're running at anything that is not divisible by 24, then you're going to get judder. If you're running your projector at 60Hz, then each frame is getting repeated 3 or 2 times, which results in visible judder (3-2 pulldown). Same thing for 75Hz, 80Hz or 85Hz.....It's not evenly divisible by 24, so some frames are going to get repeated more, resulting in judder.

Try running at 72Hz (if your projector can handle it), that way, each frame gets repeated 3 times, which should make pans silky smoothe.


-Ryan
 

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Warren,


Unchecking it in DVDGenie sets the registry key to "1" which means "enabled." It has been backwards this way for a while and still is in 4.05. It's been discussed in previous threads on setting up the ATI player. This is the way to have it for 60Hz. You can definitely see a constant micro studder if it's disabled (or checked).


I've found the jerky pans (not necessary micro-studder) can be projector dependent. Some digital projectors just produce a smoother picture at 60Hz with native resolution, no matter what. At 72Hz (or 71.928 for that matter) it may look just a tad smoother (if you really concentrate hard), but only up until a "big" jerk or two happens, which is really noticeable and annoying, and it's random.


I find it much more stable and consistently smooth for vertical or horizontal panning when set to 60Hz. And 59.94 or 60 (using Powerstrip) doesn't make any difference for me either. I don't use PS except to initially store my special resolution in the driver.


A good demonstration of display dependence, is when I move the VGA cable over to my flat panel and watch a DVD, it jerks like crazy, though it's completely smooth on my LCD projector with the same setup. This always amazes me. Yet I have another flat panel that runs fairly smooth, but using a different PC with all kinds of garbage on it. Go figure. I think once you get the software running as smooth as possible, it's a matter of finding the setting that your projector will sync to best.


Carey
 

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Discussion Starter · #9 ·
DMA is enabled using directx 8.0 plus the patch. I am using the LT150 projector so I can't run at 72z. I am running it at 70hz. I will see if running at 60 helps. I do run at the 150's native resolution of 1024x768. I have tried power strip but I did not find that it made any difference when setting sync properties to match exactly what the 150's manual stated.


what will dvd genie do for me?
 

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Actually, you need to have your refresh rate set for 71.928 if possible. You can get close to this in Power Strip. I finally got it there after having it set at 72 and the difference is quite dramatic. It doesn't seem like a small variance can make such a difference, but it does because it determines the frequency of the stutter and if you're dead on at 71.928, the chances of seeing the stutetr during a slow pan, the only time you can see them anyway, is sharply reduced.
 

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Quote:
Originally posted by Carey P


I don't use PS except to initially store my special resolution in the driver.


Carey
Carey, what is the advantage of this? Did you notice an improvement without running PS and how is it done? Interested.


John Moschella
 

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Quite often, juddering can be inherent in the movie itself. At least, I assume it is, because you can see some judder even on 35mm film presentations.


So, although the above suggestions will decrease judder to a certain extent, I imagine there will always be *some* present.


-Bon
 

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John,


There's absolutely no advantage to this. Powerstrip doesn't hurt DVD play at all. I was just pointing out that I don't need Powerstrip. I have tried the experiment (many times, in fact) of setting the refresh as close as I could to 59.94 or 71.928 and could not get any improvement over a straight 60Hz driver setting. So there's no reason to have it running while playing a DVD. If I had seen an advantage, I would certainly be using it, since fractional refresh numbers can not be stored into the driver settings (they are rounded off to integer values).


Carey
 

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Quote:
Originally posted by Bon
Quite often, juddering can be inherent in the movie itself. At least, I assume it is, because you can see some judder even on 35mm film presentations.


So, although the above suggestions will decrease judder to a certain extent, I imagine there will always be *some* present.


-Bon
I think that Bon is correct about this. I encourage everyone to go to the theater with a critical eye. You will notice judder during camera motion that is most likely the limitation of the 24 fps rate.


Carey, thanks for the explanation. My personal view is that the judder reduction dependency on refresh rate is very projector dependent. Theoretically an exact integer multiple of the approximately 24 fps rate should have the same judder as actual film.


John Moschella
 

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Quote:
Originally posted by Bon
Quite often, juddering can be inherent in the movie itself. At least, I assume it is, because you can see some judder even on 35mm film presentations.


So, although the above suggestions will decrease judder to a certain extent, I imagine there will always be *some* present.


-Bon
I went through this whole issue about a year ago. Jerky pans are caused by HTPC. I compared my DVDO iscan to Power DVD and the DVDO had no problems with jerky pans. It did however have a problem with visible scan lines on the DVDO. So I decided to live with high resolution and jerky pans.


I'm glad to see that I am not the only one who sees this. When I tried to solve this over year ago the people on the forum thought I was crazy or had my PC configured wrong. I've done all the tweaks posted here, flashed the bios on my motherboard, video card, and DVD drive, and the jerky pans are still present!!!


I think the problem is the $30 program that we have as the heart of our $10,000 systems. Cheap software never works right.


As far as 35mm goes the judder in a theater is annoying, but very different than what I see in my home theater. The Film has more of a strobe affect, whereas HTPC has more of miniature pause. It seems that it can't process the DATA fast enough.


Does anyone have smooth pans on there HTPC?


Thanks,

~Jay
 

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Jay: I do, but it's not a $30 solution. More like a $1,125 solution (SDI card plus a modded standalone player).


I think Bon's right. What we think of as judder sometimes isn't. Rather, it is a jerky pan from either the film or the DVD transfer. For the longest time I tried working out the judder from a pan at the beginning of Breakfast at Tiffany's. As it turns out, it must be in the source. Man, did I waste a lot of time on that. :D


That said, the software players seem to drop frames a lot, even on fast machines. It's not their fault; rather, it appears to be MS's video renderer DirectShow filter. The Cineplayer decoder DirectShow filter doesn't seem to send along quality information to the video renderer. Otherwise, I could quantify exactly how many frames it drops.
 

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Quote:
Originally posted by dschmelzer



That said, the software players seem to drop frames a lot, even on fast machines. It's not their fault; rather, it appears to be MS's video renderer DirectShow filter. The Cineplayer decoder DirectShow filter doesn't seem to send along quality information to the video renderer. Otherwise, I could quantify exactly how many frames it drops.
SDI isn't really what I want, I really like the ergonomics of my software player. But is Dscaler really that good? Can it really compare to software DVD players?


Maybe I don't understand how to work Dscaler, but it just doesn't look that great. My DVDO looked much better with Dish Network stuff, but Dscaler has two advantages: 1) Higher resolution, and 2) it's just a click away. The DVDO involved getting up and switching a box, and maintaining another resolution on the projector. That is why I don't use it anymore.


Is there a way around this MS DirectShow filter problem? Or better yet a way to fix it? Software DVD is SO good in every other way.


BTW I'd love to see a SDI mod for my DishPlayer;)


~Jay
 

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The fundamental problem is that HTPC's drive the DVD decoding off the audio clock rather than the video clock. Since the video clock isn't synced to the audio clock it slips over time which results in periodic skipped frames.


The dropped frames cannot be eliminated, but the period between them can be lengthened by choosing a refresh rate which corresponds to NTSC 59.94Hz (ie. 71.928Hz or 47.952Hz).


A 60Hz refresh rate will introduce 3:2 judder which masks the dropped frames. The motion is not as smooth as a 23.976 multiple but most people are accustomed to 3:2 judder on NTSC television so the judder may not be objectionable.


Professional video equipment and scalers use a genlock function to sync the incoming and outgoing refresh rates to prevent dropped frames. Standalone DVD players use a single clock for both audio and video so there is no drift between the clocks to cause dropped frames.


There are some excellent threads on stuttering in the archives:

Bjoern Roy's Judder/Stutter Guide
Are occasional missed frames/stutters normal for a HTPC?


Dave.
 

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Jay!


Yes, I have "smooth" pan's on my HTPC. I run it @59.942Hz as it is currently the best on my projector. I have tried @71.928Hz, but this only works when I'm running 800x600 on my LCD-pj???

This is quite frustrating as 71.928 looks so nice and smooth, but when you get the occasionally "studder" it just ruins the experience :-(


I have given up and are living with the 60Hz as it is pretty smooth, but I would like to some day go 3x24FPS.


Best regards,

Thomas.
 
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