Digitally projected movies

[astro]

‘Star Wars’ to bow on low-tech film (http://www.msnbc.com/news/730584.asp?0dm=C228B)

Per this story has anyone here ever seen a digitally projected movie at a move theatre? Was it better or worse than film? Was it noticeably different in any way?

Lucasfilm’s Mr. McCallum responds that even today’s digital projection would be a big improvement over what most moviegoers see at their local multiplexes. Those who watch Episode II on digital screens “should be able to see a totally flicker-free film, which I think explodes on the screen,” he says. Most important, the digital projection “looks exactly the way you made it,” he says.

[Icarus]

Yes, I saw Shrek digitally projected at a regular movie theatre. I must say that because it was a digitally animated film, I can't really say if it was better/worse or even noticable. I was indeed clear and sharp.

Ever since seeing Shrek I have been curious about the digital projection technology. Did I see a continuous moving image? Or did I see 32 still frames per second projected, as in regular film?

[Zebra]

I've seen some digital projected movies. I saw Shrek and Dinosaurs digitally projected. Again both are digital animated films so they looked really good.

I did see a 'regular' movie once (I can't remember the film) but it was being projected by two machines to make it bright enough.

Right now the image is still not quite as good. The big advantage is that the 'film' won't break or scratch or other wise degrade over time. (although it is rare that a film stays in theatres that long)

[Smeghead]

Originally posted by Icarus
I was indeed clear and sharp.


Perhaps you were, but how was the movie?

Bwahahaha!!!

[Sam Stone]

Digital does not have the contrast ratio of film, so the blacks look more like a very dark grey, which tends to make the picture look a bit 'flat'.

However, that's the comparison between perfect film and digital. The reason why the digital people keep trying to compare it to 'your multiplex' is that by the time the average person sees the film in a multiplex it's scratched, stretched, and the cineplex projectors are often dimmer than they should be. This eliminates the advantage of film.

So the bottom line is that digital won't look as good as a primo print in an excellent theater, but will look substantially better than the average film in the average multiplex.

Very few theaters are properly equipped to project the film digitally, however.

[scr4]

Originally posted by Sam Stone
Digital does not have the contrast ratio of film, so the blacks look more like a very dark grey, which tends to make the picture look a bit 'flat'.

That's interesting. Do those projectors use LCDs? I presume the limitation is the LCD and not the signal format (color depth)? In conventional terms, what's the color depth and pixel count?

[KneadToKnow]

Originally posted by Icarus
Did I see a continuous moving image? Or did I see 32 still frames per second projected, as in regular film?
You saw x still frames per second, same as in regular film. Same as on TV. Same as on your computer. Same as every other form of projecting moving images I've ever heard of.

I don't give a value for x above because it varies for the different methods I list. :)

[Green Eyed Stranger]

I have seen quite a few movies digitally projected, mainly because I work with some of the technology that's used for it. (I won't say who I work for, because I'm not speaking for them).

Even though I work with the technology, I'll try to be objective.

Currently, as far as I know, all digital projection systems installed currently aure using TI's DLP cinema projectors. You can check TI's website (http://www.dlp.com/dlp/cinema/cinema.asp) for the exact details on how they work, but basically, as I understand it, thre are 3 chips (R, G, and B) with a resolution of 1280x1024 pixels.

TI has licensed these chips to projector makers (Barco, Christie (I think), and one other I can't think of just at the moment). Supposedly these chips have a higher contrast ratio (which is the point Sam Stone brings up above). Whether or not it's as good as film, I can't say, but listening to people with better eyes than I, all I can say is that it's a mixed opinion.

JVC also has an entry for digital cinema, but as far as I know there are no installations using it at this moment. You can look at their website (http://www.jvcdig.com/digital_cinema.htm) for more info. I haven't seen it, so I won't comment on it.

At this point, I should point out that I'm basing "digital cinema" on the system that was rolled out with Toy Story 2 in November of 1999. There was another set of systems used for Episode I earlier in 1999.

At that time, and until very recently, the movies were served up by QuVIS' (www.quvis.com) QuBit server. Recently, there have been releases shown with Technicolor/Qualcomm servers, and I think a few others. This website (http://www.tech-notes.net/Dig-Cine/Digitalcinema.html) gives a nice little timeline of digital cinema.

Okay, that's a broad brush of what's currently out there, so where is it going? People in the film camp will say that digital shouldn't replace film until it can match 70mm resolution (which is a Great Debate in itself). The digital side, says that the current systems (with the 1280x1024 resolution) is similar to what the majority of people see in the theaters anyway, so why not roll it out?

Personally, I think it will come down to one thing, and one thing only: money. I think digital cinema will be a reality, simply because digital systems have overtaken every other analog system (yes I know people still buy vinyl records, and vacuum tubes).

That's broadly what I know about digital cinema. I hope it at least kinda addressed the OP.

Take care,

GES

[flex727]

Originally posted by KneadToKnow

You saw x still frames per second, same as in regular film. Same as on TV. Same as on your computer. Same as every other form of projecting moving images I've ever heard of.

I don't give a value for x above because it varies for the different methods I list. :)

Not exactly. With DLP, gray-scale is achieved by cycling the mirrors on and off extremely rapidly with duty-cycle determining brightness. The image is much smoother in this regard than film.

I've seen nearly every movie that has come out in DLP since I'm fortunate enough to have a DLP-equipped theater very near my home. I find it to be generally superior to film for a number of reasons:

Brighter, more vivid color.

Smoother image (as mentioned above), but most importantly, no "jitter" caused by the variation of each film frame registering in the projector.

No scratches, breaks, reel changes, etc.

I haven't noticed a problem with contrast ratio and I don't know if DLP is technically superior or inferior to film - it seems similar.

Disclaimer - Like GES, I have also worked directly with the technology of digital projection (though not currently). It's a fascinating demonstration of nanotechnology. I can discuss some of the technical aspects of DLP technology on request, but my in-depth knowledge is pretty limited. For anyone interested, I highly recommend the white papers online at the DLP web site (http://www.dlp.com)

[flex727]

One more thing I failed to mention: One of the most interesting things about digital projection (DLP in particular) is that it is digital throughout. The D-to-A converter is your brain. I'm not aware of any other digital technology that does that. It may be silly to say, but I think that's really cool.

[rjung]

Originally posted by flex727
One more thing I failed to mention: One of the most interesting things about digital projection (DLP in particular) is that it is digital throughout. The D-to-A converter is your brain. I'm not aware of any other digital technology that does that.
Technically speaking, wouldn't the D-to-A conversion actually be occurring when the light passes through the LCD and is projected on the screen? Because the electrons hitting the canvas ain't digital, AFAIK.

[flex727]

Originally posted by rjung

Technically speaking, wouldn't the D-to-A conversion actually be occurring when the light passes through the LCD and is projected on the screen? Because the electrons hitting the canvas ain't digital, AFAIK.

Nope. There are thousands of discrete light pulses, all of equal intensity, for each pixel of the image. The method used to achieve the grayscale is, I believe, called binary pulsewidth modulation. Here is a quote from Dr. Hornbeck's white paper (http://www.dlp.com/dlp/resources/whitepapers/mems/dplmems/3proj.asp) on the subject:

[T]he DMD accepts electrical words representing gray levels of brightness at its input and outputs optical words. Suppose, for the sake of simplicity, that the input words have 4 bits, as shown in Figure 12. Each bit in the word represents a time duration for light to be on or off (1 or 0). The time durations have relative values of 20, 21, 22, 23, or 1, 2, 4, 8. The first bit (or least significant bit, LSB) represents a duration of 1/15, the second 2/15, the third 4/15, and the fourth bit (or most significant bit, MSB) represents a duration of 8/15 of the video field time. The possible gray levels produced by all combinations of bits in the 4-bit word are (2)4 or 16 equally spaced gray levels (0, 1/15, 2/15, , 15/15). For example, (0000) = 0, (1000) = 8/15, and (1111) = 15/15. The DMD commonly uses 8-bit words, representing (2)8 or 256 possible gray levels.

Incident light is reflected from the light switches and is switched or modulated into light bundles having durations represented by each bit in the electrical word. To an observer, the light bundles occur over such a small time compared to the integration time of the eye that they give the physical sensation of light having a constant intensity represented by the value of the 4-bit input word.

The image is truly digital, in every sense, until the light enters the eye.

[Sam Stone]

Just to add to that, cheaper DLP projectors only use one chip instead of three, and use a color wheel synchronized with the panel in order to display color. That's what my NEC-LT150 does.

Other projection technologies include LCD and DILA. A DLP panel consists of hundreds of thousands of tiny mirrors which reflect light. In an LCD and DILA panel, the light shines through the panel, and the LCD's turn on and off to block light. The end result is that LCD and DILA is brighter than DLP with the same bub output, but each has a different set of drawbacks. For instance, the space between pixels in an LCD panel passes light, so the pixel 'grid' on the screen is quite visible at close distances. This is typically known as 'screendoor effect'. And because a fully-on LCD pixel still passes some light and the light spillage from the screendoor also hits the screen, it's harder to get a good contrast ratio. DLP panels don't transmit light between pixels, so it's black and hardly visible at all, and generally provides better contrast.

[flex727]

Originally posted by Sam Stone
Just to add to that, cheaper DLP projectors only use one chip instead of three, and use a color wheel synchronized with the panel in order to display color. That's what my NEC-LT150 does.

Yes, quite true. Amazing that this thing has the speed to produce three different pictures sequentially, in addition to all the grayscale stuff I mentioned in my previous post, and have it all seem to be seamlessly integrated to the eye.

Other projection technologies include LCD and DILA. A DLP panel consists of hundreds of thousands of tiny mirrors which reflect light. In an LCD and DILA panel, the light shines through the panel, and the LCD's turn on and off to block light. The end result is that LCD and DILA is brighter than DLP with the same bub output, but each has a different set of drawbacks. For instance, the space between pixels in an LCD panel passes light, so the pixel 'grid' on the screen is quite visible at close distances. This is typically known as 'screendoor effect'. And because a fully-on LCD pixel still passes some light and the light spillage from the screendoor also hits the screen, it's harder to get a good contrast ratio. DLP panels don't transmit light between pixels, so it's black and hardly visible at all, and generally provides better contrast.

I know even less about LCD panels than I do about DLP, but I think you have most of this exactly backwards.

To the best of my knowledge, DLP is much brighter than LCD. Think about it, it's like comparing light bouncing off a mirror with the same light shining through sunglasses (LCD pixels cannot become perfectly transparent, but a microscopically smooth piece of Aluminum can be pretty close to perfectly reflecting).

LCD has a "screen door" effect, but I believe that it's because the pixel frame blocks the light. Although DLP has been tremendously improved to be essentially equavalent to LCD, I think it's generally easier to get good contrast ratio with LCD. The DLP mirror has a lot of supporting structure that can potentially act as reflecting surfaces that have to be (and have been successfully) dealt with to maximize contrast ratio.

[clayton_e]

Originally posted by Icarus
I was indeed clear and sharp.

Hehe.. Can I quote you on that? :D

[Zebra]

What is 'holding up' the roll out of digital cinema is money and standards and one other thing.

First all the studios must agree on a standard of how they want their films projected. If you owned a cinema and invested in projectors that say Paramount and Universal said was OK but then later Fox and Disney said no, you would be stuck with some worthless equipment.


Then there is money. Digital cinema will actually save a lot of money, for the studios. Physical prints are expensive to make, and to ship around the country. The circuts by and large have been killing professional (union) projectionists for a long time. (which is why projection is in such a sorry state imho) So I don't think they will save much on having easier projection systems. But the circuts will have major expense in changing over to digital. They paid to have their sound systems all switched to various digital formats to remain competitive with each other. But I don't think they will go out and change all their projectors on their own.

Also consider small 'mom and pop' theatres in small towns around the country. They will probably never change. So prints of the films will still have to be made. I really don't think the circuts will ever just tell these people to drop dead.


Finally studios have to worry about security. The idea is to download the films from satallites or high speed land lines. What if the film was hacked? What if someone could be selling high digital quality DVDs in front of the theatre by Saturday instead of crappy VHS ones like they do now? I think that concern also needs to be addressed before we'll have digital cinema everywhere.

[Sam Stone]

flex727: I think I was right the first time. I've actually used a number of these projectors. DLP almost always provides better contrast ratio than LCD, and the spaces between the pixels on an LCD projector are light, and the spaces between on DLP are black.

Another issue has to do with 'fill factor' which is the size of the pixels in relation to the size of the gaps between them. The LCOS panels in a DILA projector have better fill factor, so the screen door isn't as noticable.

[ftg]

I of the reasons I don't like digital TV is because of the block-effects that occur sometimes. The easiest to notice are flashes from cameras or explosions. Fast motion in general is quite choppy. Since these seem to be the result of poorly done data compression, I was wondering if digital theater avoids the problem. E.g., us the data sent encoded with a loss-less compression system?

[flex727]

Originally posted by Sam Stone
flex727: I think I was right the first time. I've actually used a number of these projectors. DLP almost always provides better contrast ratio than LCD, and the spaces between the pixels on an LCD projector are light, and the spaces between on DLP are black.

Hmmm, you must be referring to reflective LCD. I was thinking of transmissive. This leads me to believe that the reflective LCD technology provides additional brightness at the expense of contrast ratio. I guess that would be expected.

Another issue has to do with 'fill factor' which is the size of the pixels in relation to the size of the gaps between them. The LCOS panels in a DILA projector have better fill factor, so the screen door isn't as noticable.

DLP is much superior to LCD in fill factor with only a 1 micron gap between 16 micron square pixels. My passing familiarity with DILA would say that it could potentially have 100% fill in one dimension since it uses a linear array that sweeps across the screen (single raster) to create the picture. I don't know what the gap would be in the other direction, probably similar to DLP. I would think that with a linear array of pixels, DILA would have a tremendous cost advantage, but brightness would suffer tremendously (2-3 orders of magnitude!).

[Icarus]

Originally posted by clayton_e

Originally posted by Icarus
I was indeed clear and sharp.
Hehe.. Can I quote you on that? :D
Hmmm, sounds like a good title for my autobiography, or maybe I'll have it on my tombstone.:rolleyes: