AV Magazine
Director Ang Lee’s new film The current limits of projection technology can push frame rates up to 240 and even 480fps if resolution is reduced from 4K to 2K and 3D is neglected.
The November theatrical release of Billy Lynn’s Long Halftime Walk has a groundswell of Awards buzz because of its unprecedented visual format of 4K resolution, 3D and a speed of 120 frames a second (fps - also denominated as 120p or 120Hz).
No major motion picture has ever been released at rates of 60 let alone 120, the nearest being Peter Jackson’s The Hobbit, a 48fps 3D 4K film in 2012.
Nor is this some experimental sideshow. Its director is the two-time Oscar winner Ang Lee (Brokeback Mountain, Life of Pi) and the $50 million Sony Pictures distributed Iraq war drama stars Kristen Stewart and Vin Diesel.
Yet higher frame rates have been relatively common in proAV for decades - and demand is steadily increasing, according to Barco’s Maria Dahl Aagaard, strategic marketing manager, simulation.
“This is especially evident within the projection industry and several of the high end markets it serves such as simulation and high end visitor attraction,” she says. “Within these sectors HFR helps improve the viewing experience by providing smooth life like images and suppressed motion blur artefacts. Think fast jet and racing car simulators, roller coaster dark rides and also museum-based astronomy shows. These trends are filtering into other important market segments such as rental and staging and more mainstream AV as well.”
Historically, expectations have been much lower for the consumer market which has primarily been driven by the movie and TV industry where films have been shot in 24 fps - an artefact of Hollywood’s decision to accommodate the optical soundtrack 90 years ago.
Its shortcomings include blurry images - particularly noticeable in any fast action panned movements - and strobing - immediately apparent in stereoscopic, large-format movies.
For this reason HFR is widespread in theme park 3D and 4D attractions. “When you immerse an audience in front of a large screen the fast motion can create kinetosis (motion sickness),” explains Bryan Boehme, director of sales for location based entertainment, Christie. “Humans can perceive motion at 960fps so if we can bring rates up to 120 this smooths the image out.”
The current limits of projection technology can push frame rates up to 240 and even 480fps if resolution is reduced from 4K to 2K and 3D is neglected. “Resolution is actually perceived to be greater at higher frame rates,” says Boehme. “It’s like looking through a window in comparison to the representation of an image you get with 24fps.”
A problem: Making content at such extreme frame rates is barely practical. Ang Lee is pushing production boundaries his film which consumed 40 times as much data as a conventional film.
Moreover, to shunt the data through the projector fast enough some serious horsepower is required which is why Christie’s Mirage is one of a handful of machines capable of it. It can process data at 1.2 Gigapixels a second with a Trulife electronics processor and also uses Christie laser technology to throw 28fL (72000) on screen. Even then two of them are needed to show Lee’s picture at 120fps for both eyes.
Many cinema fans will argue for the textural aesthetics of 24fps and have criticised Jackson’s use of 48 on the basis that the picture looked too much like video.
That said, trends are changing “due to the exposure from home entertainment and visitor attraction venues. People are no longer willing to settle for second best,” says Aagaard.
PC’s have always had higher refresh rates than TV but the latest TV sets into retail are incorporating 120Hz. After broadcasters like BT and Sky have rolled out 4K and high dynamic range, Ultra HD services they will turn attention to upping speed from 50/60 to 100/120 to erase the motion blur which mars fast sports action.
Douglas Trumbull, the vfx whizz who pioneered HFR motion simulation ride films in the 1970s with Showscan, is back with a new system. Magi Pod is capable of playing back 4K, 3D and 60 (per eye) using a single Christie Mirage and a hemispherically curved Torus screen. Trumbull intends to pre-fabricate the 70-seater Pods for quick install into multiplex or amusement parks.
Shooting at 120 unlocks the ability for fine control in post over ‘the look’ of the material because the camera’s shutter angle is no longer locked in to the rushes. In effect it offers a new technical and creative tool: technical because from the 120 master a number of exhibition options (e.g 2K 3D 120fps, 4K 3D 60fps) can be derived; and creative because a filmmaker could select frame rates for different moments within the same same story much as they’d use focal length, lighting or colour.
The only thing dragging back HFR from going mainstream is cultural inertia. “When cavemen drew stick paintings on rock that was state of the art,” says Boehme. “Imagine if they could see a renaissance painting. It would look much more realistic but it would also be so alien to them. It will take a while for us all to get out of our comfort zone.”
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