This is topic Weird motion artifacts during DLP presentation in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.


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Posted by Aaron Haney (Member # 747) on 05-22-2006, 10:25 PM:
 
This weekend I went to see "Over the Hedge" at the Century 22 in San Jose (on Winchester Blvd). The movie was presented via a 2K DLP projector with the Dolby Digital Cinema logo shown before the feature. Aside from the usual DLP limitations (mediocre resolution and poor black level), I was surprised to notice a strange motion articfact visible during the show.

Whenever there was an image onscreen with slow, even movement, such as slow camera pan, I could see various details in the image blur momentarily, over and over, about once every second or so. It looked like a video compression problem, although not the type I am normally used to.

It was most noticiable during the end credits, which are so blurry as to be nearly unreadable, but I also saw it at various other times during the movie, including the trailers at the beginning of the show.

Has anyone else been to this theater and noticed the problem? I've been to a lot of theatrical DLP presentations, but this is the first one I've seen with this particular defect.
 

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Posted by Tommie Evans (Member # 2674) on 05-23-2006, 01:03 PM:
 
Hi Aaron

I take it the DLP presentation you saw in 2k had the 3 mirror system and not a single mirror and colour wheel? Usually with a colour wheel if you move your head/vision from side-to-side you can see the colours 'break-down' on the contours of shapes in the image. Possibly the colour wheel had been knocked or damaged?

Another occurance, especially with computer generated images is that the over-sampling of pixels or aliasing might be ropey in some details i.e. fur and blades of grass as an example, but usually this is seen as a shimmering effect within the pixels?
 

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Posted by Darryl Spicer (Member # 711) on 05-23-2006, 04:23 PM:
 
I thought they would all be the three mirror dlp chips in use on professional equipment.
 

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Posted by Aaron Haney (Member # 747) on 05-23-2006, 04:41 PM:
 
I'm under the impression this is a three chip installation. I'm familiar with what colorwheel effects look like, and this looked very different. It also did not look like any aliasing effect I'm familiar with. It's very hard to describe. Imagine an object is moving across the screen steadily, and once every second or so, it blurs or smears along its direction of motion, just for a frame or two. I wish I could describe it more clearly, but it's one of those things you just have to see for yourself.
 

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Posted by Alan Gouger (Member # 543) on 05-23-2006, 05:24 PM:
 
Did you see this during the movie as well. If it was limited to just the intro it is possible what you saw was caused from the intro material originating from 30 FPS video.
 

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Posted by Aaron Haney (Member # 747) on 05-23-2006, 09:55 PM:
 
It was during the entire feature.
 

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Posted by Frank Angel (Member # 248) on 05-24-2006, 04:50 AM:
 
So what are you saying....there can actually be flaws in digital? GHASP! But....but, my dreams are shattered....they told us that only FILM had flaws...especially after a few showings; you know, it gets scratched and dirty and looses all its color. On the other hand, digital is the same the billionth effin time it is viewed as it is the first time.....that is, with its low contrast, poor blacks, soft images and now we discover, glory be, motion artifacts that cause in-and-out-of- focus it the camera pans. Oh my, who woulda thunk it?! It's great for STILL pictures; with movies.....not so good.

OK, enuf sarcasm....but this just goes to show, what every techie knows, that NO technology is perfect. I wish the digevangelists would just admit that and stop bashing film that has served us for a century.

It's really a matter of what exactly the imperfections are. Personally I think I am a lot more comfortable with some flects of random dirt rather than a continuous focus flutter on all camera movement once every second. And I assume this projector was relatively new....like it's probably been in service all of a year or two and played, what, a dozen or so features if that?

Yet, their's my "old technology" as they are now refering to 35mm film, my trusty Simplex XL that hasn't broken down in more years than most of the TI tech guys have been alive. Let's see the longevity track record of the current 2K digital "roll out." Bet the exhibitors who are shelling out $100,000 per screen to get on this 2K "bandwagon" (1200 screens out of 36,000...some bandwagon) are hoping it their longevity will be a tad longer than the life of those 1.3K digital projectors of the once lauded 1.3K rollout.

Ah, hope springs eternal. Sorry, guys I think the sarcastic button must be stuck.
 

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Posted by Louis Bornwasser (Member # 3063) on 05-24-2006, 09:10 AM:
 
Remember, PR being what it is, there is no ad revenue for old stuff, so 'zines will "push" that which pays the ads.

I still have never seen or heard of a completely fair "shootout". I find this to be the height of disingenuousness. Should not the wattage be matched? Should not we look at "mixed media?" (Not cartoons.) Louis
 

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Posted by Paul Konen (Member # 41) on 05-24-2006, 10:09 AM:
 
All professional DLP systems are 3 chip systems. No color wheel.

I've seen artifacts when watching Cable TV, but have yet to see it with DLP. I've been looking because of what you guys have said too.

I don't see how there could be artifacts when each frame is scanned , encoded, and projected individually. It isn't done like early internet video where you would get an initial frame and then as it played, the resolution would improve.
 

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Posted by Jack Ondracek (Member # 1466) on 05-24-2006, 11:08 AM:
 
Could this be a server problem?

During the recent demo at the Transit Drive-In, I was able to watch the server "at work" (though the problems described here weren't observed at the demo). Actually, if it weren't for a little blinking light, one wouldn't have necessarily noticed it. Assuming the flashing had something to do with periodic data transfer from the hard drive to a buffer, I wonder if that might have been related to what Aaron saw.
 

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Posted by Mattias Ohlson (Member # 1662) on 05-24-2006, 11:19 AM:
 
I think that the artifact described is called error diffusion or motion contouring. From what I understand dlp cheats in using some spatial real estate to render gradients. With moving objects there can be problems. The thing is that this artifact goes unnoticeable by many people.
I am surprised the artifact is described as so noticeable.
Thus 4k sxrd should be the choice for digital cinema.
 

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Posted by Frank Angel (Member # 248) on 05-24-2006, 12:52 PM:
 

quote: Paul Konen

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I don't see how there could be artifacts when each frame is scanned , encoded, and projected individually. It isn't done like early internet video where you would get an initial frame and then as it played, the resolution would improve.

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Development of the Digital Micromirror Device (DMD) Microsystem

9/7/2005
Author(s): Michael R. Douglass

Abstract: The Digital Micromirror Device (DMD) developed by Texas Instruments has made tremendous progress in both performance and reliability since it was first invented in 1987. From the first working concept of a bistable mirror, the DMD is now providing high-brightness, high-contrast, and high-reliability in over 5,000,000 projectors using Digital Light Processing™ technology. In recent years, the DMD has achieved the status of being a commercially successful MEMS device. The knowledge we gained through our characterization and testing helped us achieve this success. The performance of our production DMD has achieved, and in some cases exceeded, our reliability goals. For every new DMD as well as for each major design change, Texas Instruments performs a detailed failure modes and effects analysis (FMEA). This process assures the standards achieved for reliability and performance are maintained on all subsequent designs. This paper discusses some of the metrology developed for the DMD, accelerated stress testing techniques, environmental testing, unique DMD life tests, test equipment development, packaging, modeling and failure analysis. The use of characterization and testing and how they were essential to achieve our reliability goals will be discussed. Keywords: DLP™, DMD, MEMS, testing, characterization, reliability, picture reliability...

Development of DLP

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4/10/2003
Author(s): A.B. Sontheimer and D.J. Mehrl

Abstract: This paper will show how different operating conditions improve hinge memory lifetime of the Digital Micromirror Device (DMD). The correlation of parametric measurements to physical properties will also be developed. Specific operating conditions explored include the effects of (1) on/off duty cycle, (2) relaxation during nonoperation and (3) reversibility on hinge memory lifetime performance.

DLP Hinge Memory Test

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Lifetime Estimates and Unique Failure Mechanisms of the Digital Micromirror Device™

2/4/1998
Author(s): M.R. Douglass

Abstract: This paper discusses Digital Micromirror Device (DMD) reliability development activities; failure modes investigated (e.g., hinge fatigue, hinge memory, stuck mirrors, and environmental robustness); various acceleration techniques (e.g., temperature and duty cycle); corrective actions implemented; and the resulting evidence that the DMD is exceeding original reliability goals.

DLP Failure Modes

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...At sections of the [mirror] hinge where the most stress was expected, there was no evidence of dislocations, grain irregularity, or fatigue... We now estimate, as we have demonstrated [in lab tests], that [mirror] hinges will not break during at least 10 years of normal use in any application and more than 50 years in most applications. To date, we have not identified the point at which a hinge wears out.

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Yes, certainly no useful information there!

Does anyone know what the warranty is on new DLP cinema projectors? How many stuck pixels/mirrors can there be before it's considered defective?
 

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Posted by Bill Enos (Member # 440) on 05-25-2006, 08:30 AM:
 
Does anybody really believe what is in David's quoted section? When one of these things, dies how long will it take for a tech with parts, circuit boards, etc. to show up? I'm betting 2 weeks minimum, and you'd better be ready to write a check for at least five or six grand.
 

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Posted by Frank Angel (Member # 248) on 05-25-2006, 01:54 PM:
 

quote: Bill Enos

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Re DLP white papers----An engineering smoke screen-no useful information contained.

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You noticed that too, eh, Bill? They sure know how to spin it -- not that you would expect much more when the fox is testing the fencing around the chicken coop.

Although they seem to be congratulating themselves that the testing shows that they've reached their "goals," they are pretty vague about what those goals were. Will these modules be guaranteed not to have a single mirror hinge failure for 10 years or to use their own high-tech definition....getting "stuck." Obviously TI knows there is this possibility. So knowing that the hinges can fail, what happens when they do? I mean, does TI pro-rate the modules in the same way say the lamp manufacturers do? Because in my mind, a single stuck mirror....that pinpoint of wrong light or dark in an image is WAY more annoying that any fleck of dirt is with film. As far as I'm concerned, anything that is constant like that would be unacceptable -- a scratch line for example with film....same thing.

Given TI's testing, they must have some benchmark as to operation-time-to-failure, whatever it is -- they say 10 years -- that they will guarantee a perfect image without a single stuck mirror hinge. Will they replace an entire module? And what is the cost to pull the failed module and install and align a new one? That can't be an in-house maintenance procedure like replacing much of the hardware in a film projector system.

These are questions that I certainly would want to have answered before I would invest in this technology.

Then there is the practical, real-world impact. If and when hinges get stuck and it costs $$ to replace and align a new module, given what we know about the level of concern exhibitors have for image quality on their screens, how many stuck hinges do you think it will take after a module is out of warrantee, before Mr. Exhibitor will bite the bullet and spend his concessions money to replace and install? Does anyone imaging that the exhibitor who lets his lamps burn until his patrons can barely see the image is going to order a new module because he sees a single speck of errant light on the screen?

Unless TI can get the modules to simply turn off when a single hing fails and a message popup on the monitor that says, "OPERATION FAILURE -- MODULE MUST BE REPLACED TO CONTINUE" I am afraid we are going to be doomed to seeing many beautiful star-fields in blackouts.
 

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Posted by David Stambaugh (Member # 1102) on 05-25-2006, 02:12 PM:
 
Certainly the buyers of these $100K projectors are getting some kind of warranty, are satisfied that the units will perform, and have service arrangements in place. You make it sound like nobody has considered any of this. Just because nobody from a major circuit, or TI, or Dolby has posted details on these issues here doesn't mean they haven't been taken into full consideration. Give these guys at least some credit!

In 1998 (8 years ago!) TI was quoting a calculated MTBF of 119,000 hours for the DLP chips. That's undoubtedly higher now. What's the MTBF on a new Kinoton or Christie 35mm projector? How many years (or hours of operation) is a new intermittent guaranteed to perform absolutely perfectly, no wear or slop or any other problem?
 

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Posted by Bruce Hansen (Member # 281) on 05-25-2006, 06:16 PM:
 
This problem sounds like what happens in some standards conversions. Where frame rate, and number of scan lines must be changed. Could it be that the theater received the wrong type of file, and the server and/or projector are trying to standards convert it?
 

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Posted by Steve Guttag (Member # 268) on 05-25-2006, 06:16 PM:
 
David, you do give these guys too much credit...there is no real long term warranty in place. I have a customer with three DCinema DLPs that are now out of warranty...the repair bills will be huge.

As for film projectors running with their intermittent working flawlessly...one has to misuse the machine for the intermittent to fail, even after 50-years. Misuse does include not maintianing the oil level and changing it. There is very little else on this planet that has given the service life of a film projector. Especially the ones after 1950.

A problem with semiconductors is the obsolesence of the semis themselves...what if a chip goes out of production? Multiply that by how many chips are on each board and the problem grows geometrically. In order to incorporate current semiconductor availability, one may have to redesign a circuit...how long after a projector goes out of production does a manufacturer keep re-engineering a product only have yet another component need to be redesigned?

Compare that to film projectors where not only the main manufacturer makes the parts but so do 3rd party companies like Wolk and LaVezzi. Look at how many models of film projectors each manufacturer has had to come up with...as for the operation of the machine (the film part), Century has had really 2 when you get down to it...Sure the turrets and the various gates get that model count up but the GR-7 on the "C" is the same GR-7 that is on the turreted machine today...Simplex has a similar story with the Super, E-7 and XL... in that once the XL came out...all of the future "models" were really just variations that use about 90% of the same parts, particularly on the gear side.

There has never been this overwhelming need to keep coming out with new models of projectors to stave off parts that were no longer available. By the 50s, most of the projector companies really have had their final form though their earlier products are STILL running today.

The closest we've had to current machines using obsolete parts is Century's bearings...many of those are special now and one must order in the 1000s to have a reasonable price (as a supplier...hence Strong, Wolk and LaVezzi tend to be the source for them). Simplex generally still has off-the-shelf bearing sizes.

With electronics, things get very propritary. You will NEVER get the service life out of a digital projector that you can with a film projector...not unless some new technology we haven't seen comes out.

The question becomes for the digital systems is can they get the cost down such that a disposable projector is financially fesible and just how long must a projector run before it is considered no longer viable.
 

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Posted by David Stambaugh (Member # 1102) on 05-25-2006, 10:17 PM:
 
Steve, you make a lot of valid points and far be it for me to argue with you (I may be dumb but I'm not crazy! ). I do think the exhibitors are aware of all this, especially the threat of their new DLP system becoming "obsolete" in a much shorter time than conventional projectors due to evolving technology and obsolescence of electronic parts. Yet they're making the move anyway. Either the numbers crunch out better than we think, or there's something in that $5-a-bottle water the exhibitors are drinking that's affecting their business judgement.
 

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Posted by Steve Guttag (Member # 268) on 05-26-2006, 06:26 AM:
 
David, I think you last statement is the correct one...remember the industry you are talking about...what percentage of them have had bankruptcy in their legacy?
 

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Posted by Frank Angel (Member # 248) on 05-26-2006, 09:01 AM:
 
Then on the other hand, how many chains are actually moving forward with this conversion? A few big name chains, yes, but I saw somewhere that slightly less than half the screens in the country are owned by small chains and independents. Hearing that there is a buy of 170 systems here or 200 screens there doesn't exactly constitute an unstoppable semi hurdling down a mountainous downgrade. Additionally, because today a chain puts out a press release that it's committed to digital, that doesn't mean that after those 170 conversions have been in place for a year or two, they may not be saying in their board rooms or whereever the bean counters hang out, "Geez, was THAT a mistake or what?!" A couple of hundred conversions is no guarantee that any company will necessarily continue to install digital in every other 1000 or 2000 of their screens.

We all talk here very seriously and at length about the nuances of image quality, but we all know that the primary concern of corporate exhibition has never been exclusively image quality -- methinks they can live with a lot more motion artifacts and sawtooth titles than we can. In the end, digital will have to prove itself as giving them a decided, competitive, economic advantage over their competitors who don't convert or even over their non-digital booths, or those relatively few installs that they lauded in today's press releases may very well come to a screeching hault. Two or three years from now it could very easily turn out that "We are committed to the wonders of digital," could turn into, "I wish I had never said 'Bring it on.'" It won't be the first time someone was sold an expensive bill of goods only to find out later that it wasn't all it was cracked up to be.

Time will write the last chapter of this story.
 

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Posted by Tim Reed (Member # 137) on 05-26-2006, 10:00 AM:
 
Frank, you are in serious denial. NATO wants it, so that's all the impedus that is needed. Fall in line. It is happening and it's not going to go away.

Don't you remember when polyester prints became the norm? That was a NATO dictate as well.

Kiss it goodbye.

It's over.


 

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Posted by Scott Norwood (Member # 30) on 05-26-2006, 10:01 AM:
 
Agreed with the comment about how the theatre owners are (mostly) not biting.

The largest proposed installation so far is the Carmike deal, which absolutely will not result in the "up to" 2300 installations that were proposed. Look at the Carmike web site. They have more theatres this year than last, but attendance and revenues are down. They have fewer than $30 million in cash. The were late with their SEC reporting. This is not a healthy company. They can't afford a $300 million installation.

The scattered installations in select AMC/Regal/etc. houses are meaningless. If I owned 6000 screens, I'd put in a few DLP units, too. For a chain of that size, the cost of a few installations is just noise compared to their regular operating costs. They're essentially beta test sites for whenever the technology actually becomes sufficient cost-effective to be worth installing on a larger scale.

Also, consider the reports from the people who have seen the 4k Sony systems that they don't look substantially better than the 2k DLP systems. Add to that the fact that there is _still_ no standard distribution medium or file format (the DCI report was a general outline of requirements, not a standard).

If the industry were financially healthy, a large installation could happen fairly quickly, but it isn't and it won't. I'm becoming increasingly convinced that there will need to be a major reduction in the number of screens in the US in the next few years, and installing new equipment in theatres that may be closing in the forseeable future is probably not a smart move for anyone.
 

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Posted by Jack Ondracek (Member # 1466) on 05-26-2006, 11:27 AM:
 
New intermittent... around $900-ish?

New DLP chip... around $??,000...

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I'm becoming increasingly convinced that there will need to be a major reduction in the number of screens in the US in the next few years,

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quote: Tim Reed

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NATO wants it, so that's all the impedus that is needed. Fall in line. It is happening and it's not going to go away.

Don't you remember when polyester prints became the norm? That was a NATO dictate as well.

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Right now, can anyone actually demonstrate where an investment in digital equipment can give an exhibitor a financial advantage over a competitor who doesn't invest?

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quote: Frank Angel

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How long did it take for the switch to red readers or analog stereo sound?

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