JudderTest software - Page 8

Hi arca,

Will keep you updated.

Thanks and regards.

Thanks arca for the excellent software.

I've been using it with my PC with Radeon X1300 using VGA output to a Panasonic plasma 42PV500. At the default 1024x768 @ 60Hz, there is some tearing.

The magic number for me seems to be 59.801Hz, then there is almost no tearing, although close to that frequency there will be a tear slowly moving up/down the screen.

Does anybody else have experience with Juddertest and the Pannys PX500 or PV500 series?

I wonder if your database is ready? It will be an excellent resource for display owners to share their "magic numbers".

Hello, everyone.

I got fed up with jerky video playback on my Linux HTPC and Plus UP-1100P projector, so I wrote a program today to help me solve the problem.

It's a Judder Test tool for Linux. It is command-line based, rather than GUI-based like this tool, which would allow a person to include it in a bootable scripted test CD/DVD for HTPC's.

It uses OpenGL for video sync and video output, and while it lacks a few features of the Judder Test for Windows, it has a few other features I've never seen anywhere else.

I would welcome the input of anyone who has worked with the Judder Test for Windows.

Find out all about it here in the HTPC - Linux Chat forum. That thread has a link to the Judder Test for Linux home page.

Please direct your comments and suggestions to the thread linked above.

Hi all,

I m new with Juddertest. First problem I m dealing with is:
When I start judder test on my 1280x720 pj he starts running ok without drops BUT......: I can t get out of the program! I ve tried every sort of keyboard combinations (Q, ALT+TAB, CNTR+ALT+DEL, ALT+F5 etc.) but my systems hangs. Even my mouse does not move anymore. Strangely enough juddertest keeps running. I let it run for 3 minutes to see if it Quits autom. than but without result. So I had to push my on/off swith on my computer. Rebooted and tried it again for a few times but without result.....

Can anyone help here?

In the bottom right corner there is a Time Limit field.

Esc works for me

Hi,

I'm not too familiar with judder test but I am trying to use it to get my Panasonic TH42PV500 set up with a Radeon 9800 pro graphic card using the VGA input.

The following is my powerstrip string setting - 1360,56,136,256,768,5,3,27,86239,2


I had the application running, and used it to get everything just perfect ... then for some unknown reason I lost my settings following a reboot ...

Now when I try to run jddertest I get the following error -

"Failed to run judder test.

Failed while waiting for vertical blanking."

Does anyone know what is causing this runtime failure ?

Has anyone got a better setting for powerstrip for this plasma ?


I watch both NTSC & PAL content ... but the display will not operate below 55Hz ... how do I set it for PAL ?

BTW ... this is my first post ... hello and thanks in advance for any help, and forgive the newbie silly questions ... I am learning lot of new things here ...

Welcome to AVS!

It seems your videocard settings may have been messed up - perhaps vertical resync needs to be re-enabled?

Failing that, you may need to install Driver Cleaner Pro (check with Google!), uninstall the ATI drivers, reboot, run Driver Cleaner Pro with ATI selected, reboot, then install your ATI display drivers again.

Then again, the above may not work. Good luck!

Thanks ...

This is getting strange ... got up this morning ... can't remember what I did but ... judder test now works !!!

I think it may have been due to an adjustment I made to ATI catalyst 3d settings ... there is an option "wait for vertical refresh" which I set to always off ... but I can't be sure.

I now have the display set up so that it does not drop any frames in a 60s test .. but I notice some tearing about 1/3 distance from the top of the screen ... it is not that visible with bar speed 1 but from 2 upwards it starts to become very visible ... I tried adjusting front porch, back porch, vertical frequency, plasma clock phase, plasma clock but it seem difficult to adjust out ... it may be fine, but any advice ?

Here is my best powerstrip string - 1360,56,136,256,768,6,3,23,85919,2

Judder is a great tool by the way .. not only is it good for adjusting your screen ... but for those of us learning it gives a great idea how video displays work. Thanks to the author ...

Just a suggestion but ... if you are not accepting money for it why not set up a voluntary donation to charity via pay pal or something ... give people the option to express their gratitude...

Personally, I'd love JudderTest to go Opensource and also accept donations - I'd love to add a 3:2 pulldown simulation to it.

I think you will have to find a different refresh rate to eliminate tearing too. It will take a lot of trial and error to find the right frequency.

I suggest starting with 59.94 hz - that is the standard NTSC refresh rate.

EDIT: Arca beat me to it. Thanks again for the excellent software! It's also a great way to test if any background processes are interfering - if JudderTest is reporting too many dropped frames start removing processes or services.

Is there nothing at sysinternals_com to monitor process activity in real time with minimal CPU/RAM load ?

... I tried the settings you gave me for powerstrip, thanks... Definite improvement, Frequency is spot on but still a little tearing ... will have to play around to see if I can get it any better. At least there is no frame loss ...

Perhaps the best thing to do it use the HDMI input on the plasma rather than the VGA. But there are pro's and con's to that too ... not least the fact the Panasonic don't recommend it.

... one conclusion I am starting to believe ... this stuff is still the domain of tech savvy and/or hobbyist ... Microsoft HTPC's are not really ready for mass market ...

Lets see how they do with Vista .. I await with scepticism ... and probably my next PC will be a Mac!

Newbie here............I have a Sony VPLHS20 PJ which I use PowerStrip to achieve the 56Hz refresh required timing for 1368x768 1:1 native rez support. The Sony EDID only goes to 1024x768....ugh. Anyway, I'm using TheaterTek 2.x with FFDShow 2X resize & filters with SP-DIF audio pass-through to AV amp/receiver. I do not use reclock and my DVDs (NTSC) are stored on HDDs for playback. I currenly don't see much Judders or Stutters but I've also dropped my FFDShow settings so my P4 2.8Ghz CPU is only at ~ 40% usage on playback. I have a Radeon 9600XT with Cat6.7 drivers thru a DVI-D link to PJ.

So, here is my question........how do I setup/config JudderTest for the above ? I guess I'm not catching the meanings of the settings, etc. ? What am I looking for ?

Also, I looked at Reclock as a way to see what was happening on my HTPC but I notice its real trick/focus is to sync the frame rate to the refresh rate to eliminate audio sync issues.....well my ~ 56Hz HS20 allows me little latitude for refersh change to achieve 1368x768 and I didn't want to install Reclock when currently I don't have audio lip sync issues.

Please help a newbie on setup tutorial....I've read the thread and guess I'm a little dense.

Thanks !

Juddertest needs to have Powerstrip installed, otherwise it won't run.

I suggest setting the bar speed to 5 or 10 when doing your test - I find that is the best speed for finding stutter/tearing when trying out different frequencies.

Also, be careful that you don't mistake stutter due to frame drops versus stutter because of a refresh rate mismatch. Juddertest is EXTREMELY sensitive to whatever is running on your PC - frame drops can occur so watch out for those! Too many and you will see what looks like stutter - you will need to eliminate any framedrops because of background programs first before you can verify that your projector is in sync with your videocard.

I'm not sure how Reclock can help you with such an oddball refresh rate on that projector.

Would you mind outlining a quick setup/config tutorial and what to look for ? I'm trying to read the thread and no real detail. I have not installed so maybe it is straight forward but was looking for a quick how-to for NTSC analysis.

As far as Reclock....I don't have lip sync issues....believe it or not with 56Hz refresh and NTSC playback but I was going to install to view the frame drop analysis function. Looks like JudderTest may be easier/better without inducing other factors that ReClock might.

Anyway, any help would be appreciated.

Just extract the zip file into a directory. Make sure Powerstrip is running.

Run Juddertest. It should automatically pull the timings from Powerstrip. Select the desired bar speed - try 5. Leave everything else alone.

Click on the "Judder Test" button. Watch the green bars scroll by. They should scroll smoothly with no hiccups or tearing.

Also watch the frame drop counter - if everything is perfect it should stay at 0. If you get one or two, but it never goes up after that, then you are probably okay - this means there aren't any background processes that are interfering with Juddertest.

If there are no frame drops, and you see stutter or tearing, that means the videocard's refresh rate isn't perfectly synced with your projector. You will have to adjust the timings - it will take trial and error! The closer you are, the less frequent the stutter/tearing will be.

My criteria is that there should be no stutter or tearing for at least 5 minutes. Staring at these bars for 5 minutes can be a challenge though - watch your health!

Thank You !

Question.....this whole thread talks about the fact that PJs and HDTVs are fixed frequency. I take it means at a certain rez. Example, my undocumented, un-EDID 1368x768 1:1 rez at 56Hz for the Sony VPLHS20. So, if in fact this is truly fixed the thread shows folks as you say "tweeking" the PS timings. I guess my question is that "fixed" means kinda-fixed around the 56Hza until it doesn't sync ? If so, how much % up and down around the "fixed" frequency is there typically ?

Usually the video refresh rate that you tweak is slightly different from the display's refresh rate - usually because of variances in the hardware. For example, some people have their videocard's output 60.1 hz instead of 60.00 hz because one (or both!) of the device's video clocks are very slighly off. Nothing is perfect!

My wild guess, based on my very very limited experience with displays (a 19" CRT monitor and a Benq 8700+ DLP projector) is that your refresh rate can be within .02% (point zero two) and you couldn't tell the difference.

If you are off by 1% you WILL notice a stutter/tear however. Here is a formula for predicting when a stutter will occur:

Take the refresh rate of your video card and subtract the refresh rate of your display. Invert the value and that will be how many seconds the video will play smooth before stuttering.

For example, if your display expects 60.000 hz at 1280x720 (like my Benq 8700+), but you told the videocard to output a refresh rate of 59.94 hz, then you will get a stutter at:

1 / (59.94 hz - 60.00h z) = 16.6666s (ignore the negative sign)

So you will get a stutter at around every 17 seconds, even though it is only off by .1%!

If your videocard's clocks is perfectly accurate, AND the input clock of your display is also perfect, then you will not get a stutter if the refresh rates match perfectly.

Well, I ran the test and it seems to perform fine....however, really haven't tried at length. Some questions.
1) How do you exit from the test ? I tried ESC, ALT+F4, no luck.
2) The bars in my limited test seem to progress smooth with no stutter or tearing. However, the right edge of the bar is a little "fuzzy". Is this normal of the motion or is the bars supposed to be rock soild green rectangles ?
3) I see the timings and refresh but I thought this test showed not only my PS timings from the HTPC to PJ but what the PJ was actually driving internally the LCDs at ? I realize the test itself is showing any effect of the difference but I thought there was some OSD label to show both Hz refresh rates ?

Lastly, as FYI to other readers I found my Sony VPLHS20 that requires 56Hz refresh for 1368x768 support has a sync/out-of-sync range of 1Hz...basically 55.9Hz to 56.9Hz.

Thanks.

1) Press Q.
2) The fuzziness may be an artifact of the projector. They are supposed to be perfectly smooth on a perfect display. I wouldn't worry about it as long as you have 1:1 pixel mapping.
3) It is impossible for the PC to know what the projector is driving the panel at. You will only see what Powerstrip thinks the videocard is outputing at. Remember, clock crystals on the videocard can differ from what Powerstrip displays, and the clock crystals in your projector can also have error.

The goal of Juddertest is to ensure, visually, that the refresh rates of the PC and the display match. When they match you eliminate stutters/tears.

It is possible for displays to automatically sync with input devices, within a certain range. If you run Juddertest using a multisync CRT monitor, it should always be perfectly smooth no matter what refresh rate you choose. It is very rare for a digital display to do the same however.

Have fun.

I gather you can adjust the PS timings real time in the test or before you hit run ? I think I'd only be tweeking the Refresh/Hz rate but wanted a quick how-to before I tried and fried.

Yep you can. It should be self-explanatory.

Powerstrip does not work with the new generation nvidiacards (G80). Is there any possibility to run Juddertest without powerstrip?

Sounds like a good feature request! Arca?

Acually I found out that I can run PS with my card but the reported timings are totally screwed up. The new nvidiacards have totally different drivers (thats why PS is not supporting them)

I can't run JudderTest, powerstrip is running but reports that odd error appeared some pages ago...

Failed to run judder test.

Failed while waiting for vertical blanking.

Here's the PS string: 1280,48,32,80,800,2,6,15,71308,6

Picture (I can't put it inside an URL, too tiny post count...)
img444.imageshack.us/img444/6678/juddertestdf9.jpg

Any clue? Thanks...

What videocard and video drivers?