Future Developments of Digital Cinema

February 11, 2013
By

Preamble

I’d watched a DVD screener of Skyfall, and this highly compressed facsimile was a mere 1/10th of the resolution of the 2k original.[1] My wife wanted to see it in the theater, so after I’d already watched it on my computer I enjoyed it in the theater as well. But in the theater, I really started to notice things like the sets, the makeup, how craggy Daniel Craig is getting, and (uh-oh) chromatic aberration from the Master Primes the film was lensed with (citation needed). I almost enjoyed it more on my computer screen, because I was watching a story, whereas in the theater I became more conscious of the craft. Perhaps the lack of visual detail in the DVD screener forced my brain to actively fill in the gaps, engaging my subconscious in an exercise in imagination, whereas the 2k projection made everything very literal.

Then, the other night, I was watching (and thoroughly enjoying) an episode of Strikeback from Cinemax, and realized that just about everything I watch is at 640×360 resolution or less, and almost every 45-minute show compressed to something like 350 MB. And yet they are enjoyable. Meanwhile, I’m reading the cinematography blogs about all the other technologies that start to feel like total overkill. “4k television, is coming.” Cue the glorious music. I’m trying to keep abreast of Sony / Canon / Red’s 4k camera offerings… “4k and beyond,” is what one blog post oozed, with an air of almost suffocating optimism, as though universal justice and world peace and sustainable ecology would all be within reach, if only we could grasp in our hands the mighty silver bullet of 8k (gasp!) capture…but there’s just so much new gear out there all the time that it is a career unto itself just keeping up.  “Oh man,” I thought, “I’m watching and enjoying a show that’s one fortieth of the resolution of 4k capture and projection…maybe I need to see the optometrist.”

And then I had an epiphany: I suddenly felt I knew where the evolution of digital cinema is going. Spoiler alert: it’s not about more pixels. That is, more pixels will always be a marketing gimmick, but 2.5 K is a threshold beyond which the returns are diminishingly small. 4k in cinema is sort of like that 24-bit 96khz capture in the audio world. It’s just a number, since no one can see the difference between 2.5k and 4k on the big screen anyway. Prophetically, This Is Spinal Tap has a scene that could very well go down in history as the zeitgeist of the digital age – “It goes to eleven.”

The Big Epiphany

Digital cinema technology is following precisely the same path of evolution that audio and photography technology followed in bygone decades. It starts out as a grainy novelty, a pale shadow of the real thing, and advances until it crosses the threshold of verisimilitude.  Once a recording technology, be it audio, still photograph, or moving pictures, crosses the threshold where the recording cannot perceivably be distinguished from the real thing, audiences say, okay, good enough. Then the technicians dig in, and start really exploring how to maximize their signal within such a finely-threaded yet extremely broad canvass. But as the CAPTURE of high-fidelity audio, photography and video becomes more and more accessible, it is still the DELIVERY of these recordings that still requires the highest-end equipment. For digital cinema, delivery is where the next phase of evolution will naturally take place, since there aren’t any practical delivery pipelines that come anywhere close to representing the true quality of the original image.

History I – Evolution of Audio

Audio recording brought the orchestra into people’s homes, but it was like listening to that orchestra through a telephone. You could identify the song, but there was no dynamic range in volume, the bass was nonexistent and the highs were muddy. Fast forward through the iterations of vinyl, tape, digital and now “lossless” compressed audio, and even audiophiles admit that 24-bit 98khz sampling is…well…overkill.  A palm-held device like the H4N absolutely smokes the high-end recording studio of a couple decades ago. The CAPTURE phase of high quality audio recording and delivery has been democratized.

With the Capture phase exhaustively evolved, technicians have, for the last couple of decades, been metaphorically stretching their limbs.  Ever notice that all your MP3’s and CD’s originating from the early 1990’s onward are just louder than your golden oldies? Compare a Simon and Garfunkel disk (not the remastered one) to one from Norah Jones. Norah croons louder. The lack of noise in the digital recording formats combined with compression and expansion effects in mastering allowed recording engineers to use a broader range of volume. The quiet bits are even more quiet, the louder bits are louder. There is now more creative space for the artist to explore the medium.

As for DELIVERY: My Bose Quiet Comfort 15‘s are nice, I’d even say good enough, but Audio in movie theaters is now capable of delivering frequencies so low you can’t hear them but you feel them in your chest, and frequencies so high our inner hound can only whimper. Volumes so low you can barely hear them, and volumes so high your ear turns them into distortion. Movie theater surround-sound puts the bad guy back over your left shoulder and the incoming jet to your front left. The evolution of capture and presentation technologies is essentially complete; what remains is the democratization of these ultra-high-level and still very expensive sound systems. We’re closer now than we’ve ever been, with living-room surround-sound systems; they’re still a bit pricy, and most people consider a decent pair of stereo speakers to be good enough. The really really good sound delivery system you buy now is still going to be really really good in 50 years…because 50 years from now the human species is still going to have the same pairs of ears.

History II – Evolution of Photography

As photography evolved, it all but killed realistic painting as an art form since even early photographs could reproduce reality more faithfully. Portraits were no longer just for the self-celebrating dynasties of rich patrons, but became accessible to everyone. Cameras got smaller and found their way into people’s hands. Fast forward through the evolution of 4×5 plates, nitrate-based film on a roll, 35mm Kodachrome…in the here and now, even consumer-level DSLR cameras take photographs with more detail than the naked eye can see, and with HDR photography, a greater latitude than the eye can see. Even the camera manufacturers feel that the 24-36 megapixel range is “enough.” If you want to tweak your pictures after-the-fact, 16-bit RAW gives you lots to play with.

In the photography world, we of course have a range of lenses that squash and expand physical space, tilt/shift lenses that distort perspective, lenses and cameras that can literally see in the dark, or on the other hand take pictures of the disk of the sun. We can take photographs through telescopes of other corners of the universe, we can take pictures of infra-red and ultraviolet spectrums, x-rays and so on…in other words, photography has developed beyond the limitations of our eye.

As with the evolution of audio, the capture phase has evolved, perhaps beyond the simple plateau of “good enough” all the way to the heights of insanely ridiculous. At the pro and consumer level, manufacturers are now struggling to make lenses good enough to resolve the resolutions available, since the very properties of the wavelengths of light are becoming a bottle neck, spawning the development of exotic aspherical lenses and coatings to corral that troublesome quantum-level distortion into the genie’s bottle. “Damn it, Lisa, I just bought this 36-megapixel Nikon and when I zoom in to 800% magnification, the letters on the pill bottle in the background are a little fuzzy.” I mean, jeeze.

The Capture being thus evolved, the technicians now get busy to explore the vast possibilities…in the same way that modern CD’s are louder than the old ones, today’s photographs are now stretched and tuned in ways never before possible. HDR photography, for example, compresses a wider range of tonal values into the smaller digital container of the 16-bit RGB photograph. Photo stitching automatically combines multiple images into 360° panoramas. And then there’s Instagram…

The main limitation is still DELIVERY. Take, for instance, my MacBook Pro 17” LED screen. Or your Cinema display, or your full-raster HDTV, your Sony Bravia or what have you. These screens have great color, great contrast, they’re sharp as hell, and photos look great on them. Or do they? Here’s the kind of thing I do for shits and giggles – I recently took out my spot meter and measured the contrast range of full black to full white on my computer screen. Surprise – only five stops of dynamic range. That means that the eleven-stop range on my 5D-MkIII is being represented in the tiny five-stop range of my laptop screen. Hmmm….what about print? Same thing – under a bright light, and in ideal conditions, the best photo reproductions have a 5-stop range between pure black and pure white. Maybe someone needs to invent darker black ink. As for the question of resolution…I can’t see the pixels on my screen until I get really close, so yeah, 1920×1200 is good enough. The over-sampling of a Retina display is nice, but not nicer enough to really care.

I’ve now arrived at the main point of this whole article, which is really this: The CAPTURE phase of digital cinema has never been better…but the DELIVERY technology still pretty much sucks.

So, skipping now to…

History III – Evolution of Digital Cinema

Lumiere, blah blah blah, mise-en-scene, blah blah blah, Potemkin, Citizen Kane, blah blah…the Dogme group…blah blah blah…and the evolution of cinema to its present form…which is still in flux. Peter Jackson’s technologically hyphenated 48-fps-4k-3D Hobbit may very well represent the most informationally dense visual spectacle since that noble tribe of refugee slaves beheld Jim Jannard parting the Red Sea — oops, that was a typo — I meant Moses, of course. The Hobbit should be retitled The Goliath. It’s projected at double the frame rate, four times the pixels of a 2K projection, all in visual stereo, which equates to 2 x 4 x 2, or sixteen times more visual information splashed up on the screen than the projection of a conventional movie. Advocates for high frame rates and high resolutions are so convinced that this is better, that even when confronted with a fairly meh audience response, they proclaim; “It really is better, people just have to get used to it.”

One thing that people can not get used to is the botched job many theaters make of 3D projection, which involves using polarizing filters that block half of the light coming from the projector. The 3D glasses block another half of the light, so that what you see is only 1/4 as bright as a 2D movie. People complain, simply, that 3D movies are too dark. Which leads us right back to dynamic range.

Conclusion

Significantly better than our computer / iPad / HDTV screens, the digital projectors at the cinema has the capability of delivering a 2000:1 contrast range. But much more common are the projectors rated for a 1000:1 contrast ratio. But these are only the advertised numbers – you need the ideal screen, the right viewing angle and distance, and the bulb in your projector has got to be brand spanking new. And hopefully the theater’s green Exit signs aren’t casting a horrid green glow into the shadows. Most theaters deliver contrast ratios between 250:1 and 500:1, but sometimes as low as 60:1 in the case of 3D theaters that have done it the cheap way. Which is…drumroll…between 6 and 9 stops of dynamic range.

The ALEXA captures a 14-stop dynamic range. Written on the side of a digital projector, this would be a 16,000:1 contrast range.

Put another way, if the dynamic range of the audio delivery were this poor, the loudest explosion we’d hear would be about the same as a dog barking in the exit row, and the quietest signal would sound like a car idling in the front of the screen. Lots of floor noise, no really high volumes at all.

So, my “eureka” moment really boils down to: the future of digital cinema is greater latitude – possibly in capture, but certainly in delivery. Until consumer devices and movie theaters give us brighter brights and darker darks, we’re still looking at pale shadows. Even if they are at mind-boggling resolution.

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Pretentious footnote:

[1] The 2.35:1 aspect ratio requires cropping a 640×360 video down to 640×272, and a 2k projection is cropped to 2048×871 pixels. The former totals 174,080 pixels, the latter totals 1,783,808 pixels. Thus a fairly standard format for streaming video and delivering content over the web is 1/10th the resolution of a 2k projection.

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