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UK to Build Network of 150 Digital Cinemas
mikael writes "According to this article at the BBC, a network of 250 digital screens in 150 cinemas across the country is being planned. Each film is losslessly compressed from 1 Terabyte down to 100 Gigabytes and encrypted onto a portable hard disk drive with a key unique to each cinema, which is then delivered to the cinema. Each cinema projector will be capable of showing films at resolutions of 2048 x 1080 pixels. "The key benefit is the distribution and screening of documentaries, British and foreign language films, as making a digital copy is considerably cheaper than spending over £1500 pounds to make a copy of a single film". Other benefits include better picture quality and the ability to show more films each day." The UK Film Council has a brief overview of the project as well.
Subject says it all. There's something fishy about a feature film at 1080p24 compressed "losslessly" down to 100GB. That's 573GB (yes, bytes) per hour uncomrpessed, assuming 24 bits per pixel. Even D5 compression isn't lossless, and that's 5:1.
Film canned at 3000DPI is assumed to have all useable details captured. If the film this is replacing is 35mm (1 x 1.5 inches)then a resolution of 3000x4500 is required for replacement. 2048x1080 falls a bit short.
Blessed are the pessimists, for they have made backups. -- 0 1 My two bits
2048 x 1080 = 2211840 pixels per frame
3 bytes per pixel (24 bit color) = 6635520 bytes per frame
24 frames per second (to match the framerate of regular film) = 159252480 bytes per second = 151.875 megabytes per second
1 terabyte = 1024 * 1024 megabytes = 1048576 megabytes
Therefore 1 terabyte is 6904.204 seconds of video
6094.204 / 60 = 115.070 minutes of video
That's just over 1 hour, 55 minutes of video.
Sounds pretty reasonable for most movies; I guess they'd need 2 hard drives for movies longer than that, which I guess wouldn't add all that much to the cost of distribution since a 100 Gb hard drive is what, 50 bucks?
I'd be more interested in learning what kind of hard drives they have that can read 151.875 Megabytes per second continuously. I'd imagine that if you don't use a filesystem and just stream raw video off of the drive it would help because the drive wouldn't do any seeking. Still, 151.875 Megabytes sustainable must require some kind of high end SCSI drive so I guess my original supposition of $50/hard drive must be off.
I'd say that this is an idea whose time has definitely come.
It says "visually lossless". That is marketingspeak for "awful quality but no man in the street will notice".
Compare to digital tv.
Um, one slight problem. If you shoot digital and project digigtal, the final projected image is what you shot in the camera with an extra compression step on top.
If you shoot 35mm film, you get your negative, you cut the negative, you create a duplicate of the negative, then you create more duplicate negatives from that, then you finally create prints from those duplicate negatives. So by the time it gets to the cinema screen it's not unusual for a 35mm print to have gone through four or five _analogue_ copying stages from the original film negative.
As a result, the resolution of a final 35mm print is almost certainly substantially less than 2048x1080, whereas digital holds that resolution from start to finish (absent crappy compression schemes).
If you shoot 35mm film, you get your negative, you cut the negative, you create a duplicate of the negative, then you create more duplicate negatives from that, then you finally create prints from those duplicate negatives. So by the time it gets to the cinema screen it's not unusual for a 35mm print to have gone through four or five _analogue_ copying stages from the original film negative.
Er, ignoring digital editing systems that cut at least one step out of that process, I'm not sure where you're getting "four or five" analogue copying stages even out of your own example.
"You get your negative" - this is the original film. "You cut your negative" - this is still the original film. "You create a duplicate of the negative" - ok, this is copy 1. "You create more duplicate negatives" - this is copy 2. You're not making copies of copies, you're making a bunch of copies from one original. "You finally create prints from those duplicate negatives" - this is copy 3. So, only three copies are made through the most laborious process possible - and digital editing systems cut one copy out of that.
Not to mention that film has been around for more than 100 years and so much R&D and technological advancement has gone into it over that time that the quality loss is really minimal through every stage. Sure, if you kept making copies of copies of copies of copies, eventually you'd see a real resolution difference from the original; but you won't in any commercial film.
As a result, the resolution of a final 35mm print is almost certainly substantially less than 2048x1080, whereas digital holds that resolution from start to finish (absent crappy compression schemes).
Different film stocks have different grain properties, and it's the size and distribution of the grains (the crystals) that hold the detail in analog film. Some film stocks have more than 3,000 crystals per inch, some have less. But all would be significantly and noticeably higher in resolution and detail than 2048x1080 digital resolution even after the production process was complete and all copies made.
I have seen several commercial films shot, edited and projected digitally - including Final Fantasy: The Spirits Within and the last Star Wars. They looked good - cleaner than film prints, surely - but there was noticeable and obvious (to me) pixelization and aliasing throughout the films. Most people probably wouldn't have noticed and/or cared, especially in the absence of the analog "noise" caused by film grain, but it was clear to me that either the projection system or the films themselves did not have the actual resolution of their film counterparts. I don't know what the resolution of the projection systems used in the US is, but I doubt it's much (if at all) lower than 2048x1080.
1) Original Negative
2) Positive Negative (copy on negative masked stock)
3) Dupe Negative (negative again) (digital editing here)
4) Copy Negative (positive)
5) Print Negative (shipped to theatres)
And no, you still have lots of resolution left at that point. I know people that have made the films you speak of, and matching curves between series was one of their most prized accomplishments.
(yes I worked for Kodak)
Are there such things as video projectors that accept an encrypted stream of data?
/. summary said, but near-lossless, probably a Fraunhofer MP4 encoding set to a medium to high quality setting.
Yes, which is what these systems will be using. Fraunhofer-gessellschaft (of MP3 encoder fame) is the technology behind these projectors. The stream is encrypted the entire length of the data path until it hits the electronics driving the LCD screen. Each server has a key built in, supposedly impossible to recover without destroying the system. Each film to be distributed is encrypted with both a master key, and the private half of the projector's key. There are several stages of decryption, allowing a mostly uncompressed and decrypted stream to be presented to the final stage electronics. The decryption at the projector stage is lightweight, as it is less likely to be subjected to a significant cryptographic attack because it relies on having fully authenticated equipment elsewhere in the chain.
The servers regularly contact an authentication centre, so that audits can be made as to the number of showings. The servers also come with tamper-resistant housings which then disable the system until it can once again contact the auth centre. There is a bunch of other security stuff, the projectors are never sold, but only licensed to the theatre for a fixed time and have to be returned or inspected at regular intervals.
From the article, it sounds like they only have the "medium" quality screens going in, at 2k by 1k pixels. This means they'll only be installed in smaller theatres, because such low resolution looks really bad on larger screens. Also, the compression isn't lossless, like the
F-G will be showing off these projectors this year at CeBit, according to marketing bumpf I got from them recently. This BBC story is probably based on a press release from the building tsunami of announcements leading up to CeBit.
the AC
Hemos is like...sci-fi fans;he thinks technology is cool, but he hasn't bothered to understand the science it's based on