How High Frame Rate 3-D Works


Will audiences ultimately embrace high frame rate 3-D? The jury’s still out.
© ChinaFotoPress/Getty Images

For all of the billions of dollars that Hollywood has dumped into movie production over the past century, it's an industry that's been curiously stuck when it comes to certain aspects of motion picture technology. That's especially true regarding frame rates and 3-D movies.

Now that digital technology has triumphed over film, one of the biggest advances in video is high frame rate shooting. High frame rate video is just that — it has higher frame rates than have traditionally been used in motion picture recordings. Frame rates generally refer to frames per second (fps), the number of discrete images a device displays for every second of playback.

Frame rates matter. In the early 1900s, films had no sound, and these silent movies were generally shot at frame rates between 15 and 20 fps. Those speeds are a visual tipping point of sorts, one at which our eyes begin to see a succession of images as moving video instead of just a sequence of still pictures.

In the 1930s, more and more films featured audio. At very low frame rates, audio didn't play back properly with the images; unintended noise was a byproduct of slower frame rates and it interfered with sound quality. So film directors opted for 24 fps, a rate at which video and audio played well together and created a pleasing onscreen effect for audiences. Furthermore — and significantly — 24 fps didn't consume an inordinate length of film, so it helped keep costs down. It was the advent of the 24 fps standard, which has been in widespread use ever since.

In the past few years, digital video has achieved a level of quality that surpasses film, and one of the most beautiful aspects of digital is that it doesn't eat up film. Instead, everything is recorded to reusable media such as flash drives, which means that you can shoot higher frame rates without worrying about blowing your entire budget on film.

As you can probably imagine, higher frame rates are a boon to the additional depth and dimension of 3-D content.

Frame Rate Firsts

Calculating the budget for old-school film used to be a significant part of the moviemaking process. Digital media frees up filmmakers from that limitation.
Calculating the budget for old-school film used to be a significant part of the moviemaking process. Digital media frees up filmmakers from that limitation.
© philipimage/ThinkStock

Film isn't free. Suppliers charge productions per foot of film, which is equivalent to about 18 frames. When crews shoot many feet of film per day, costs can skyrocket in a hurry. Thanks to reusable digital media, directors are now exploring high frame rate video, which can hit 60 or even 80 fps.

What's the point of higher frame rates? After all, researchers say that your eyes can't really distinguish between individual images at all once you go faster than around 50 fps. But at these rapid speeds you'll notice that scenes look crisper and that motion often seems to flow more smoothly.

You can see a simulated example of the differences at this website, and also at this Red camera corporate page. Notice the striking differences in motion blur and sharpness as frame rate increases.

Now, add those high frame rates to today's ever-improving 3-D technology and you start imagining the sort of retina-ravishing content that directors might be able to conjure. It's called high frame rate 3-D (HFR 3-D), and it typically refers to content shot at 48 fps or faster. It completely changes the look and feel of 3-D flicks.

That's in large part thanks to the fact that 3-D movies are often challenging to watch, even for people with strong stomachs. It all has to do with the physics of light. If you're not up to speed on how 3-D works, be sure to read How RealD 3-D Works and How is digital 3-D different from old 3-D movies?

In short, because you have two eyes with two slightly different perspectives on your environment, movies shot in 3-D must have two cameras, too. Each camera captures data that will be seen by either your left or right eye. The polarized glasses you wear in the theater act as a decoding device of sorts, each allowing only the visuals intended for the appropriate eye. Your brain then fuses the images together into an illusion of 3-D.

The HFR System

Peter Jackson, director of “The Hobbit,” is one of high frame rate 3-D’s biggest proponents.
Peter Jackson, director of “The Hobbit,” is one of high frame rate 3-D’s biggest proponents.
© Jenna Blake/Corbis

You need a sophisticated system to play back digital HFR 3-D data onto a movie screen. This system comprises three fundamental parts, including a storage device, media block and a digitalcinema projector.

Usually, a server computer stores all of the movie content on a hard drive. The data streams from the server to the media block via a high-definition serial digital interface (HD-SDI) cable. The media block plays a vital role, decrypting and decoding the data into a format that works with the projector.

Because of the massive amount of data involved with HFR 3-D, a cable interface is often too slow, strangling the data flow and affecting image quality. So some newer systems integrate the server and media block into a compact piece of hardware that's installed directly into the projector.

After the media block unlocks the data for playback, the final piece of the system is the digital cinema projector. A vast majority of theaters use Texas Instruments' DLP Cinema technology, which can display 3-D content with a single projector.

And that leads us back to frame rates. 3-D movies shot in 24 fps often seem blurrier, especially in fast-moving action scenes. In these instances, the images never seem to meld, leaving your eyes confused and, potentially, your stomach lurching. This is where 48 fps HFR 3-D proves its value. Action sequences seem much smoother and more vivid.

At 48 fps, 3-D movies have much less stuttering and flickering. Audiences see each individual frame of the movie twice per second (called double-flashing), which means each eye sees 96 fps – altogether, both of your eyes are absorbing 192 fps.

Director Peter Jackson's series of "The Hobbit" was the first major release of a high frame rate movie in history. "The Hobbit: An Unexpected Journey" was released in 2012. It was followed by "The Hobbit: The Desolation of Smaug" in 2013 and "The Hobbit: The Battle of the Five Armies" in 2014.

All three movies were shot at 48 fps and in 3-D. They were also converted to 24 fps, 2-D versions for audiences that didn't want to see 3-D and also for theaters not equipped to project high frame rate 3-D movies.

Shooting at 48 fps is one thing. Playing back the content is another. For example, if you shoot a movie at a high frame rate, you need a projection system capable of displaying high frame rates, too, otherwise your high-speed video is pointless. Not many theaters have high-speed projectors, but they're coming.

The TV Paradox

High frame rate 3-D cameras are being used to capture all the action at sporting events.
High frame rate 3-D cameras are being used to capture all the action at sporting events.
© Ronald Martinez/Getty Images

For many people the distinct look of 24 fps video is what makes movies cinematic. Purists who truly love the 24 fps film experience, complete with all of its blurring, stuttering and visible artifacts often decry high frame rate video. They say it looks too inorganic, too artificial, too cheap and too cold to relay the kind of emotional connection of film. It looks too much, they say, as if you are simply on a movie set or watching a behind-the-scenes documentary.

Digital proponents admit that there is a period of acclimation required for your eyes to get used to the clarity and lifelike scenes of high frame rate video. Once your eyes and mind get accustomed to the effects, they argue, there's no going back to film.

They liken this transition as similar to the shift from vinyl to compact disc. Although some music lovers say nothing beats the warm sounds from a spinning record, the technical perfection of digital formats is certainly more precise and, in hindsight, it's obvious which format won out.

Television broadcasts have been using frame rates at higher than 50 fps for decades. And with the advent of HDTV broadcasts, particularly with sporting events, it's clear that viewers love the high resolution, detail and sharpness of digital. It could be that these kinds of broadcasts will be a gateway of sorts for the expectations of a new generation of audiences. Perhaps if young people are weaned on higher frame rate productions, it will become a new normal and film will begin to look outdated and primitive by comparison.

A Question of Content

For years, critics have lambasted movies that incorporate 3-D. Much of that criticism is valid, in large part because many recent movies were shot in 2-D and then converted to 3-D after the fact. Those results can be pretty dreadful, with cluttered, multi-dimensional scenes lacking visual coherence of any kind.

Just as viewers may need time to adjust to the clarity of HFR 3-D, so too do the studio personnel who make the content. Not every director has access to the kinds of budgets allocated to films such as "The Hobbit," meaning other films may look rather amateurish by comparison until cinematographers learn to use their new tools.

In addition, directors must learn to envision stories as HFR 3-D experiences from the outset. They'll have to set up each scene ultimately from the perspective of moviegoers, thinking about how to use 3-D to draw each viewer's eyes to a particular part of a scene at each moment of the film.

However, high frame rate video is incredibly easy to mishandle, largely because it reveals any flaws in movie sets, costumes and makeup. Viewers see each and every teensy detail of every moment of the movie, and any aspect that doesn't suspend your disbelief becomes a glaring mistake that detracts from the experience and makes it less satisfying.

To that end, many critics and proponents alike believe that HFR 3-D may have a place only in certain types of feature films. Director Peter Jackson says that epic, action-oriented films with sweeping battlefield views are some of the best applications of the technology. In these sequences, HFR 3-D adds many layers of depth to the scene, making it more realistic and more engrossing. It's as if viewers are plunked right into the middle of the action. But is that enough to drive HFR as a defining technology in cinema?

High Frame Rate's Future

Like his colleague Peter Jackson, James Cameron is a fan of high frame rate 3-D. He’s using it for his upcoming sequels to “Avatar.”
Like his colleague Peter Jackson, James Cameron is a fan of high frame rate 3-D. He’s using it for his upcoming sequels to “Avatar.”
©Fabrice Coffrini/AFP/Getty Images

Less than a decade ago, hardly any theaters had the digital projectors needed to show digital 3-D movies. Now there are tens of thousands of well-equipped theaters all over the world, but theater owners are once again faced with new technology, wondering whether they need to move to HRF-capable projection systems.

If Hollywood doesn't go all-in on high frame rate 3-D content, then there's no reason for theaters to invest in new equipment. As such, if you don't live in major metropolitan area, you may have to do some traveling to find a facility that supports HFR 3-D.

There's also the larger question of how long it will take studios to truly embrace HFR 3-D. To date, "The Hobbit" movies are the only ones to use this technology. Director James Cameron is expected to shoot HFR 3-D for two sequels to "Avatar" (which may even be shot at 60 fps), but beyond those two film franchises it's anyone's guess as to whether HFR 3-D will really take hold. At present, it is very much a fringe technology and it may never make permanent inroads into the industry.

If HFR 3-D is to triumph, movie production teams will have to get savvier and change their approach to maximize their impact. Makeup and costume artists, lighting teams and set builders will all need to expect that every minute detail of their work will be exposed onscreen. Special effects and computer-generated effects artists will face the same challenges. Directors will somehow have to balance the immense clarity of HFR 3-D with compelling narrative and be sure that the technology doesn't somehow overshadow the tale.

If they succeed, perhaps a nearly century-old film standard will finally fall by the wayside. If they fail, perhaps we'll be waiting for a new recording technology to somehow grab audiences in the way that 24 fps film does now.

Author's Note: How High Frame Rate 3-D Works

Directors like Peter Jackson and James Cameron aren't content with sitting on today's technology. They see the infinite possibilities in the digital filming technologies and they want to blaze new trails in cinematography. As with all pioneers who smash against known boundaries, it's impossible to say whether they'll eventually make a new way forward in filmmaking or if other digital side roads will sidetrack HFR 3-D. Final answers are probably a long time coming — these movies take years to plan and shoot. But if ambitious directors can make critical and financial successes from their technological adventures, it's a good bet that HFR 3-D will stick around for a least a few more years.

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Sources

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