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Discussion Starter · #1 ·
I am using my laptop and the VGA (15pin)monitor out to go into my Epson 5000XB LCD projector's 15 pin computer in jack. The Laptop has the Rage Mobility M1 AGP video card. The projector is an 800x600. I'm using PowerDVD.DVD movie scenes which feature lots of action, sudden bright light, or very deep colors show an occasional, but annoying, horizontal line that slowly travels up the picture. It goes away as soon as the action dies down.Otherwise, the picture is excellent and much better than using the S video port of the projector. Help!!!! Are there any custom resolution or refresh rates? Using Powerstrip, I've tried everything from 60 - 85khz. Some are better than others, but none make it go away
 

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I use an Epson 5000 with no such symptom- Macs or PC.

Maybe a few details will help, such as color of line, does the image tear at the line, does the rate of travel change with refresh rate, does it happen under battery power, etc.

Also, does the same symptom occur with a problem scene recorded to disk, and played back?

Good luck...

apg
 

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If you can use another source (pref PC) to the PJ then you can at least start to eliminate the suspects...


If you can get the PJ working as desired with another source it will obviously be the laptop... Once (if) this is the case posting in the HTPC forum will get you better answers for this issue...


One problem is Laptops are not the best of devices to be trying to do this with but you should be able to get at least adequate results...


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Discussion Starter · #4 ·
Thanks for your reply to my post concerning horizontal line with the Epson 5000XB. I spent a Lot of time working on this last night. I used my Desktop computer with Intel 810 chipset (Presario 5000 with DVD Express) this time to output to the projector--same problem. You asked for specifics. The horizontal line has no color really, I guess above and below it, the picture is not exactly lined up. When I used 1024x768 and Espons "resize" button, the horizontal line more or less stayed in the middle of the screen as opposed to travelling upwards. Any more help? kjaalto
 

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The "discontinuity" in the picture you are seeing is in all likelihood a downconversion artifact going from an anamorhpic widescreen DVD to 800X600 resolution display, in both cases. As you note, there is no actual line, just a sort of break in the picture continuity.


To playback anamorhpic DVD on a PC with square pixels (that's how computer displays work, as opposed to video), you need 848X480. Some display chips can downconvert without obvious artifacts; many, like the Matrox G400, the Rage series, can't. So you see this artifact you describe.


Regards,


Jon
 

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kjaalto,


Have you tried a different VGA cable? Some of the cheaper ones can cause odd problems. Also, do you have anything else connected to the projector (i.e. audio cables)? If so, try removing them. Also, try plugging the projector power cable into one of those 3 pin to 2 pin plug adapters (to remove the groung pin). I had a ground loop problem that was eliminated that way.
 

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Entering Sherlock mode:

Since the line moves vertically, we can eliminate a flakey LCD pixel row or frame buffer in the projector.

The line symptoms change with Laptop resolution. Could be that line noise or a ground loop problem getting into laptop frame buffer... does it go away when laptop is running on batteries _with power supply disconnected_?

Since the image appears to tear at the line, and the line doesn't have apparent color, it would appear that this is a de-interlacing problem in the laptop software.

_But_, the same symptoms appear using hardware decoding in a desktop. Back to a projector fault...

What we still haven't eliminated, though, is interference.

I once saw something similar when my refrigerator compressor used to kick in, on my computer monitor- I put the monitor on a surge suppressor, and no more problem.

So, if you have a surge suppressor handy, or can borrow one- try that for both projector and computer. It may also be that you have a VGA cable with a flakey shield. (Flakey signal lines give color abberations, and flakey sync gives jitter.)

apg
 

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Discussion Starter · #8 ·
Thanks to all who replied. I'm still having my problem. I've done a whole lot of experimenting with this and have had a lot on contact with Epson, who are not much help. They tell me to use the S-video in (which does not show the "tearing" problem I'll admit, but the picture is no where as good) I decided to try an experiment where I tried to display a simple digital photograph (.jpeg file) and "move" it around by using the slider bar to pan across the otherwise still picture. The same tearing problem! (son's head goes slightly left while body stays in position while panning horizontally across the photo) Keep in mind that both DVD and photos do not show this problem when displayed on my laptop's built in screen. Does this tell anybody anything about what's going on? I've tried every refresh rate known to man (and my video card) and can make the problem SLIGHTLY better (by going to a higher refresh rate, like 100) or worse by going lower, but I can't find the one that makes this problem go to an acceptable level.

HELP!!!
 

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Man, do I feel your pain. I, too, had the same projector with the same problem and it pretty much killed my hope of getting a cheap LCD just for fun. What you're describing is, indeed, screen tearing, and it's only seen on the computer inputs, whether it's dScaler, dvd, or just moving a window. It does not appear on the video inputs, but the internal scaler is pretty bad. At the time I had the problem, I did some searching on screen tearing and found this thread:
http://www.avsforum.com/ubb/Forum10/HTML/004509.html


Here is the pertinent information:


posted 02-07-2001 12:37 PM
Quote:
Originally posted on 02-07-2001 12:37 PM by Larry Davis:
What you are describing is a classic example of tearing. Your projector doesn't do triple buffering, unlike the Davis DL450/DLS8/Cinema One. It's likely that by lowering the refresh rate, you will reduce the visibility of the tearing. Since this is a projector issue and not a scaler/player one, to fix the problem, you will need a new projector.
I only wonder why apg isn't seeing this problem.
 

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Can you try

1) plugging your PC in a different outlet (try from the same one as the projector.)


2) try different resolutions / frequency on your PC


3) try connecting to a monitor (to make sure the image coming out of the laptop is not the problem


 

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Hello,

If the problem happens during bright flashes and action type scenes only and not with S-Video then your gamma setting may be too high. I have seen some projectors behave like this and it was always because of the gamma setting.I don't know the reason for this but it does happen.

I can make my projector do the very same thing when I turn up the gamma setting to high on my JVC-D721BK DVD player. Works with S-Video but not with Component or RGB.

I hope this helps you out.


Avery


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[This message has been edited by thxave (edited 07-06-2001).]
 

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Have you tried turning off the display on the laptop? That is, so that only the projector is being driven? If you have, have you also tried it with both the laptop and the projector being driven?


Also, try setting your desktop resolution to 800x600 vs 1024x768.



As an aside, I tried driving a 1024x768 DLP compaq projector with both my PC and my laptop. The PC could do 1024x768 and looked incredible on the projector. The laptop could only do 800x600 and looked absolutely awful on the projector.

 

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"I only wonder why apg isn't seeing this problem."


I just had a projector party on the Fourth. Twenty people, outdoors, from our HT Collective. Sony VAIO feeding an Epson 5000. We watched "Tremors" I looked specifically for any kind of artifacts related to tearing, synchronization, dropped frames, etc. We all looked. Other than a few dropped frames in the first few minutes, taken care of by tweaking Windows, the picture looked great. Absolutely no signs of tearing. SVGA @60Hz.

BTW, the image when using NTSC out of the VAIO was bloody awful. SVGA out was fine...

apg

 

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Quote:
Originally posted by apg:


[snip]


We watched "Tremors" I looked specifically for any kind of artifacts related to tearing, synchronization, dropped frames, etc. We all looked. Other than a few dropped frames in the first few minutes, taken care of by tweaking Windows, the picture looked great. Absolutely no signs of tearing. SVGA @60Hz.


[snip]
Huh, that gives me hope. You don't have to look hard for this problem. On my projector, it was very obvious when there was any fast motion, regardless of what program I was using. I had just figured it was a projector hardware problem, but I guess I'm gonna have to try again. Maybe it has to do with the different flavors of the 5000. Some have the problem, some don't.
 

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Since the projector is 800x600 native, the computer should probably be set to that. I had disappointing results w/ a 800x600 native DLP when I tried to boost the resolution up a notch, even though the projector's max resolution was 1024x768. I couldn't tell from kjaalto's posting(s) exactly which resolutions he is trying from the laptop.


One reason apg might not have the problem could be the model(s) in question. Kjaalto's says he's using an EPSON 5000 "XB" model whilst apg sounds like he might be using the 5000. (without the "XB"? -- perhaps one rev earlier)? Projectorcentral.COM does show different contrast ratio and ANSI lumen specs between the two, as well as slightly different H-V Synch ranges.


I'm awaiting an EPSON 7000 XB in the mail and praying it doesn't have the same problem. If anyone knows it does, feel free to burst my bubble (gently).


[This message has been edited by Jude (edited 07-06-2001).]
 

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Discussion Starter · #17 ·
I have been spending way too much time on this! Maybe I should just give up. HOWEVER, this weekend I tried to play with the gamma setting. It did not fix the problem, but along the way I discovered something very interesting. Just to bring you up to date, I have tried both Power DVD and DVD Express, and the problem exists with both programs, so I don't think it's the software. I have been altering refresh rates, etc, with Powerstrip but here's the interesting thing. I first tried to adjust the gamma setting using Powerstrip. When I made slight or drastic adjustments, everthing BUT the DVD window got lighter or darker! In other words, the gamma adjustments I was making with Powerstrip had no effect on the movie that was showing in the Power DVD window!!! Does this mean that all the refresh rate changes I have been making using Powerstrip have not been being applied to the DVD window? I eventually went into the Epson projectors color adjustments and adjusted the gamma there. Of course, everything on the screen responded to this--but no luck removing the tearing.

Finally, for today, if this is simply a projectors inability to handle video (jpeg, mpeg) what is the explanation? Why can any CRT monitor or laptop display I have tried handle it with no problem and this (in 1998) $4500 projector can't????? Remember, when I simply bring up a jpeg photo and use the slider bar to pan across, the tearing occurs. This is not something a data grade projector should have a problem with. If I had a lot of animation in a Powerpoint presentation, would I have this problem? I bet I would. Just don't feel like spending a few more hours designing one!!! I'm getting on the horn with Epson today. Wonder if they'll give me a 5000, which APG says works great?
 

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Quote:
Originally posted by kjaalto:
In other words, the gamma adjustments I was making with Powerstrip had no effect on the movie that was showing in the Power DVD window!!!
I believe in powerstrip there's a separate checkbox if the gamma adjustments are to apply to the overlay (where the DVD window is) vs. the desktop.


I believe that the problem with tearing, when no triple buffering is done, is that all parts of the screen are not updated simultaneously. So say the top half has 1 frame, and the bottom half has the next frame. That's why you see a discontinuity on pans. But for fixed motion, you won't see any problems.


My projector (Davis DLX650 clone) had a tearing problem, until there was a firmware upgrade to do triple-buffering. I actually didn't really notice the tearing at first, but once I saw it, I could see it all the time.


Mike





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"Kjaalto's says he's using an EPSON 5000 "XB" model whilst apg sounds like he might be using the 5000. (without the "XB"? -- perhaps one rev earlier)?"


As far as I can tell, the two models, (And the 7000/7000XB XGA models), are all the same. XB stands for "Extra Bright"- it uses a higher wattage bulb assembly, but the power supply, circuitry, optics appear to be identical.

_However_,there was some problem with the Sony power supply modules on the earliest 5000; Epsons warranty service specifically points out that any 5000 projectors with an apparent blown bulb should be sent pack for repair. When I did so, (After only 14 hours on it...), the service slip said power supply replaced. It still had the original bulb.

Unlikely that this has any bearing on kjaalto's problem, but one never knows...

apg

 

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Discussion Starter · #20 ·
Thanks APG. You know, now that you mention it, every once and while (especially after I travel with the projector) I'll push the power button and the lamp will not come on! To solve this I unscrew the bulb cover, remove the bulb and then replace it (same bulb). Voila! It comes on with no problem. This power supply thing might not be the cause of my tearing problem as you say, but it gives me a leg to stand on with Epson. I'm waiting for a call back from them as we speak.


Can anyone define "triple buffering" for me, and is it a feature one would normally know about by looking at the specifications for a given projector?
 
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