CurtPalme.com Home Theater Forum

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

Greetings folks,

A while back after posting on here about the "jail bar" ringing I was getting with my Marquee, I went out and scored a nice deal on a VP so I could manually adjust porch settings to get around the ringing. I ended up with the following settings:

H-Shift: 356, H-Front: 110, H-Sync: 44, H-Back: 356, V-Shift: 38, V-Front: 9, V-Sync: 5, V-Back: 28

As a result of this change, I ended up with what I would describe as "jitter". Not sure if that's the proper term. Basically the image "shakes" left-to-right by a very minute distance, back and forth, fairly rapidly. It's super noticeable if you're standing right in front of the screen, not so much if you're in seating position watching a movie, but you can still see it if you're looking for it. Still, we're shooting for perfection here, right? Smile

My video path is: VP->HDMI->Denon->HDMI->HDFury2->RGBHV->PJ
The jitter is still there if I remove the Denon from the chain.

I thought this must be caused by cheap cabling. I didn't have a proper VGA->RGBHV cable at the time so I bought a used one from a computer surplus store to use until I got everything going. My assumption seemed to be confirmed by the fact that if I went completely analog (VP->RGBHV->PJ) the jitter went away (not a workable long term solution since I watch bluray).

So I got new cables today from Monoprice, and unfortunately I'm still seeing the jitter! I've tried the following configs:

VP->15ft HDMI->HDFury2->1ft RGBHV->PJ

VP->3ft HDMI->HDFury2->1ft RGBHV->12ft RGBHV->PJ

I'm starting to think the culprit might be the HDFury2. Is that possible? Any ideas on what else I can try to fix the jitter?

Cheers,
Joe

**AnalogRocks** · Posted: Thu Mar 26, 2009 5:26 am Post subject:

Try playing with your H sync numbers and maybe reduce the H porch pixels a bit ( 88ish? ). I had horizontal jitter on my PC to my RPTV when I had the wrong porch settings.

I've since wiped that PC out so I can't give you specific numbers sorry.

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

Thanks AR. I'll give it a shot. Honestly I'm a bit lost when it comes to messing with these values. Not sure exactly how to go about it. All I know is that if I change it too much from what I listed above then the sides of the image start getting chopped off. H-sync is pretty finicky - a little bit of change generally causes the whole image to go haywire.

Btw, I have no jitter if the connection is completely analog, so I'm not sure if the porch settings are to blame here.

**AnalogRocks** · Posted: Thu Mar 26, 2009 5:36 am Post subject:

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

I'm just shooting for plain ol' 1080p60.

HDFury2 is left shifted? I never saw that with it hooked up to my RP-CRT. It is true that if I use the standard timings for 1080p then the image is shifted to the left, but based on other threads I'd read I thought this was common for Marquee's and 1080p signals from bluray players and such. Didn't think it was the fault of the HDFury2. Confused

Can you clarify for this newbie what exactly you mean by "give yourself more horizontal offset to the right"? Thanks.

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

Hey AR, you rock. Thanks for suggesting I keep tweaking the porch values. For some reason I had bad luck before messing with the H-Sync, but I tried again and came out with completely different timings that don't cause the jitter. sweet!

H-Shift: 276
H-Front: 4
H-Sync: 227
H-Back: 276
V-Shift: 36
V-Front: 4
V-Sync: 5
V-Back: 36

I still wonder why it was working fine before with the old timings when the video chain was all analog, but it's hard to care when everything is working ok now. Very Happy

**Curt Palme** · Posted: Thu Mar 26, 2009 12:35 pm Post subject:

http://www.youtube.com/watch?v=OBAsxLKC1Dk

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

Now I know what porch settings the Beattles had that made them shake so much. Very Happy

**AnalogRocks** · Posted: Thu Mar 26, 2009 4:52 pm Post subject:

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

There's something funny going on with my DVDO VP50Pro. I can put in custom porch/sync settings that don't cause jitter, HOWEVER, if I change to a different resolution and then back to my custom res (say I'm using 1440x960 then later want to go back to my custom 1080p) the jitter comes back! The settings are exactly the same as before, so I'm totally confused. The only way I've found to get rid of the jitter is to start from scratch at the standard 1080p timings and then customize the porch/sync values again back to where I had them before. Does this make any sense? Am I doing something wrong?

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

I've tried over a dozen different timings, they all work fine (no jitter) until I switch to another resolution and then back to the custom one. Then the jitter appears. I'm at a loss for what else to try. Any thoughts on whether this is a pj issue or a VP issue?

1031 · Joined: 22 Mar 2006 Posts: 657 Location: Finland

Hard to say is that Vp or projector issue? Back when i had DVDO HD+ it has some issues with custom resolutions (i did 1080i with custom timings and if i changed resolution for different source then my custom 1080i was changed to 1080P??)
But with my VP-50 i havent noticed similar issues that you have noticed.
Btw. Do you have original belly fans in place? I have had some raster jitter with different belly fans. Now with Papst fans rasters are near as stable as they are with original fans.

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

stock fans as far as I know.

what can I do to isolate the issue as pj or vp?

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

btw, is it at all possible this might be caused by the HDFury2?

1031 · Joined: 22 Mar 2006 Posts: 657 Location: Finland

Groundloop is one possibility.. unconnect all sources from Vp-50 and see if jitter goes away. Use Vp´s internal patterns and see if there is jitter when sources are unconnect.

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

I think I've narrowed this down to the HDFury2. Does that sound crazy? Here's what I see:

- When I output from the VP's RGBHV output instead of HDMI, the picture looks pristine. I can change and customize resolutions 'till the cows come home and the jitter doesn't appear.

- I just so happen to have my rev1 HDFury2 still lying around (currently using rev3), and guess what happens when I hook the rev1 up instead of the rev3? The jitter behavior is different - in fact it's "mostly" gone. Instead of a constant left-right shaking, it jumps left-right a tiny bit once every 3-to-5 seconds.

It'd help me to know if anyone else is pushing custom timings (especially for 1080p) through the HDFury2. Or am I the only one that hasn't jumped on the Moome train. Smile

schmoe · Joined: 30 Mar 2008 Posts: 374 Location: Seattle, WA

Here's a video of what the jitter looks like. I put a piece of masking tape with a black vertical line on the screen to give a reference point for the jitter.

Oh, and another reason I suspect the HDFury2: If I switch the colorspace output on the VP from RGB to YCbCr, then the image gets *really* nasty. Things start to distort. Check out this video. It's hard to blame this on anything but the HDFury2, correct me if I'm wrong. Can't be the cables, especially when YCbCr is a lower bandwidth signal to begin with (right?). The HDFury2 has to do more "work" to convert YCbCr to RGB and this is the result. I suppose it could still be the VP, but that seems exceedingly unlikely to me, especially when analog output works fine.