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Unless the DCI changes course, fast, the point will be largely moot. DCI 4K is higher resolution than 4k UHD; but 4k UHD hardware is available right now (with the cheap seats down to under $1000, and the 'walk into a Sony store and look rich and clueless' option still likely to set you back only ~$5k). DCI 4K gear is... niche. Not only is it almost entirely high end projectors designed for commercial movie theaters (and priced accordingly), the DCI writes their specs with all the paranoia, loathing, and pathological aversion to user friendliness that you'd expect from an organization composed of the big seven film studios writing a standard to 'protect' their precious content from being obtained in very, very, high quality digitized form once distributed to theaters. (If you thought that HDCP was a nuisance, check out Section 9. Who wouldn't want a projector where support for FIPS 140-2 level 3 is mandatory, and you can blank the embedded keys just by opening the case incorrectly? The spec also covers actual video-related stuff; but the section on DRM, logging, phoning home, and per-showing authorization was not written with customers in mind.)

It's a pity, because I'd like to see the format with more pixels win; but it would be quite a shock if DCI remains anything other than a morass of acronyms designed to keep movie theaters on a very, very, tight lease until their eventual bankruptcy. "This film has been modified from its original version. It has been formatted to fit your screen." will live on for another generation...

4K TV? I guess that's covered under the HDMI supported resolutions.

There is no agreed-upon standard for displaying 4K content in consumer electronics (DCI handles pro equipment), although the HDMI specification theoretically supports two different resolutions at 24-30Hz. I am not looking forward to my clients buying all these amazing [sic] 1st-gen 4K TVs that won't be compatible with any of the source devices coming out in the next couple years.

For example, most movie projectors advance from one frame to the next one 24 times each second. But each frame is illuminated two or three times before the next frame is projected using a shutter in front of its lamp. As a result, the movie projector runs at 24 frames per second, but has a 48 or 72 Hz refresh rate.

Now, the above is probably referring to older film projectors. While I don't know much about cinema projection technology, I have heard that most of the digital equipment used by movie theaters is designed to project at 24 fps, but that the specification for the hardware/software currently used by most theaters calls for it to be capable of 48. (source:DCI) So, 48 fps is not really a "new thing" but is simply an extension of current hardware capabilities. Also, the way I understand conversion technology, when converting to a format for display on a TV it is much easier to use tricks like 3:2 pulldown and interlacing to convert from 24 or 48 fps to the NTSC (60 Hz) or PAL (50 Hz) standards (some sources are sped up from 24 to 25 fps during conversion to PAL) than it is to convert 50 fps to something that can be shown on NTSC equipment. Perhaps someone with more experience in this field could shed some light on this?

I own and operate a movie theatre, and I had my 35mm film equipment removed and replaced with a digital cinema setup earlier this year. In place of my film projector, lamphouse and platter I now have a rackmount cinema server and a digital projector. It takes up a lot less space in the projection room.

The movie studios are pushing for theatres to convert to digital due to the cost savings from not having to create all of those prints on film.

Digital movies and trailers are currently distributed on CRU hard drives. There is talk of going to satellite distribution instead, but at the moment I get hard drives couriered to me in Pelican cases. I copy the movie from the CRU drive onto a raid in my cinema server. Once the CRU drive is copied onto the server I'm done with it and can put it back in the case it came in; the movie actually plays directly from the server.

My picture is brighter and crisper than it ever was with film, it's rock-steady with absolutely no jitter, and scratches and dust are a non-issue. The sound is also vastly better than what I had with film.

My customers don't really seem to notice the picture quality, but I have had a lot of comments and compliments on the digital cinema sound.

There is an official specification for digtal cinema.

From the point of view of the guy who operates this stuff (I'm a projectionist, of course) digital is a lot easier and less time consuming than playing movies on film. The cinema server works like a giant ipod -- I copy the movie onto the server (which takes a half-hour or so but I just go away and come back when it's done), then set up a playlist with all of the trailers and whatever else I want to show with it, and insert cues to do things like turn the lights up and down in the auditorium. The playlist takes about ten minutes to set up. That's it. I press Play to start each show, and at the end of the week I spent two minutes hitting Delete to erase the old movie.

Compare that to film, where I would spend an hour or so getting the movie off of the shipping reels and onto the platter, then spend a half-hour per day cleaning and oiling the projector, plus five minutes threading up each movie on the projector. And another 40 minutes or so tearing the movie down and putting it back on the shipping reels when I've finished playing that movie.

The negative side of the digital versus film is that a fault is less obvious. If the film is buggered up or a gear on the projector is stripped it's usually pretty easy to see the fault and possibly fix it or take steps to deal with it somehow before there is an actual problem that keeps the movie off-screen. (I've actually hand cranked my platter to keep the movie going when one of the motors quit in the middle of a show.) A fault in the digital is both less obvious and more likely to be impossible for the projectionist (me) to fix and deal with.

But digital cinema is sure nice. Having spent my life working with film to this point I wasn't really sure that I would like it, but having had the digital cinema setup for a number of months now I won't say that I miss film. As far as I'm concerned it's all about the results and I'm providing a better presentation for the customers now than I ever could before, so what's not to like?

In some ways digital is probably more idiot-proof than film.

I'd been hoping we'd skip HD and Blu-Ray and go to one of those higher-density mediums one hears about on Slashdot every few weeks. Both formats still require too much compression.

We're not there yet. We're probably there when we get 2K high images at 72FPS without compression artifacts. Somewhere around 72FPS, the annoying strobing on pans disappears. Or, in other words, football games finally look right. Football games are hard because the background is moving, there's action moving in different directions, and viewers care about the detail. The motion compression algorithms can't really handle that situation.

The digital cinema industry has a standard for this. They have two formats, "2K", which is simply 1080p, that is, 1080x2048 pixels, and "4K", which is 2160x4096 pixels. They define two speeds; 24FPS and 48FPS. Color depth is 12 bits. Compression is JPEG 2000. Maximum image data per frame is 1,302,083 bytes (which is actually smaller than you'd expect). Audio is sampled at 96KHz with a depth of 24 bits, and is not compressed. There are 16 audio channels. That's the Hollywood/SMTPE definition of a "movie" in the digital era.

In actual practice, most films now being distributed digitally are going out in "2K" mode, at 24 FPS,with 8 audio channels. The spec has headroom to double each of those numbers.

A 2-hour movie at all the highest ratings is about 500GB. So that's what needs to be delivered to the consumer. Neither HD nor Blu-Ray can do that yet.

I actually had a chance to meet with Walt Ordway, the head of DCI's technology branch, at my school a few years ago (he's a Northeastern University Alumnus). He gave a really nice presentation about what they're doing to secure the distribution masters and minimize piracy. Basically, they have a Digital Source Master (DCM) which is a final cut of the movie in a high definition format taken directly from post-processing. From this, they make various distribution masters in different formats for DVD, TV, Airline showings, and also conversion to film masters. One of the masters they make is a Digital Cinema Distribution Master. After processing, this is what is actually sent to the cinemas.

After all the video, audio, subtitle, and auxiliary data channels (things like cues for curtains, theater lighting, etc.) are compressed and packaged, it's encrypted via AES with a 128-bit key. Along with the compression and encryption process, a watermark is embedded into the video source. The Digital Cinema Package (DCP), as it is now called, is delivered to the theater via satellite uplink, hard drive delivery, internet, etc. However, the encryption key is delivered separately, via secure courier, and each theater will get a different key. The DCP is uploaded into a central server in the theater, where it will then be scheduled by the manager to be loaded into a specific screen on a set schedule. Each screen will have a digital projector along with its own server to store a local copy of the DCP.

Key entry and decryption only actually happens when the movie is played, and as everything is decrypted, the forensic watermark is added to the video as well as the audio. This watermark is unique not only to the theater, but to the specific projector and even the time that it was played. This ensures that if anyone is sitting in a theater with a camcorder, they can trace it back to the exact showing using the embedded watermarks.

If anyone is interested in checking out the Digital Cinema System Specifications, they were awarded final approval on July 20, 2005 and can be found at http://www.dcimovies.com/DCI_Digital_Cinema_System _Spec_v1.pdf

The Digital Cinema Package file (reference) sent to cinemas is indeed encrypted (as well as digitally signed). The high speed data link between a playout server at the cinema and the projector is also encrypted.

I would not consider myself an expert, but this is my field, so let me give everyone a REALLY quick lesson in 1) JPEG2000 and 2) "lossy" video compression.

JPEG2000 is an advanced set of tools for video compression. It is used at the highest levels of distribution, and has been proposed for consumer use as is the case here. For more on JPEG2000 a decent primer is here.

If you are watching content at home, it already has gone through a "lossy" compression scheme. Whether it is DTH satellite MPEG2 or MPEG4), cable (MPEG2/NTSC - yes NTSC is a lossy compression scheme), or terrestrial (MPEG2 ATSC or NTSC), DVD (MPEG2), or even LaserDisc (NTSC), your content has gone through a lossy scheme.

Remember, Google is your friend, and although not perfect, wikipedia can answer many questions. For more on video compression here is a nice little presentation.

The short story is everyone shouldn't get real upset about JPEG2000 and it being lossy. Cheers.

Yes, of course the reason it's not ready is due to steaming piles of DRM crap.

I found the Digital Cinema Initiative homepage and I looked over the DCI_Digital_Cinema_System_Spec_v1.pdf

Some 60% to 80% of the one-hundred-and-seventy-six page specification is nothing but monstrous piles of DRM on top of DRM on top of DRM.

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Yes, of course the reason it's not ready is due to steaming piles of DRM crap.

I found the Digital Cinema Initiative homepage and I looked over the DCI_Digital_Cinema_System_Spec_v1.pdf

Some 60% to 80% of the one-hundred-and-seventy-six page specification is nothing but monstrous piles of DRM on top of DRM on top of DRM.

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3.1.4.2. Frame Rates The DCDM image structure is required to support a frame rate of 24.000 Hz. The DCDM image structure can also support a frame rate of 48.000 Hz for 2K image content only. The frame rate of any individual DCDM master is required to remain constant. Metadata is carried in the image data file format to indicate the frame rate.

The defined image sizes are 2048 x 1080 (called "2K images") or 4096 x 2160 (called "4K images"), with 12-bit RGB color. The "2K" format is basically 1080p HDTV at the screen, but with better (or at least less) compression for transport. Audio is uncompressed.