In motion picture technology—eitherfilm orvideo—high frame rate (HFR) refers to higherframe rates than typical prior practice.
The frame rate for motion picture film cameras was typically 24 frames per second (FPS) with multiple flashes on each frame during projection to prevent flicker. Analog television and video employedinterlacing where only half of the image (known as avideo field) was recorded and played back/refreshed at once but at twice the rate of what would be allowed for progressive video of the same bandwidth, resulting in smoother playback, as opposed toprogressive video which is more similar to how celluloid works. The frame rate of analog television and video systems was either 50 or 60 frames per second. Usage of frame rates higher than 24 fps for feature motion pictures and higher than 30 fps for other applications are emerging trends. Filmmakers may capture their projects in a high frame rate so that it can be evenly converted to multiple lower rates for distribution.
In early theater history, there was no standardframe rate established.Thomas Edison's early films were shot at 40 fps, while theLumière Brothers used 16 fps. This had to do with a combination of the use of a hand crank rather than a motor, which created variable frame rates because of the inconsistency of the cranking of the film through the camera. After the introduction ofsynch sound recording, 24 fps became the industry standard frame rate for capture and projection of motion pictures.[1] 24 fps was chosen because it was the minimum frame rate that would produce adequate sound quality. This was done because film was expensive, and using the lowest possible frame rate would use the least amount of film.[2]
A few film formats have experimented with frame rates higher than the standard 24 fps. The original 3-stripCinerama features of the 1950s ran at 26 fps.[3] The first twoTodd-AO70 mm features,Oklahoma! (1955) andAround the World in 80 Days (1956) were shot and projected at 30 fps.[4]Douglas Trumbull's 70 mmShowscan film format operated at 60 fps.[5]
TheIMAX HD filmMomentum, presented atSeville Expo '92, was shot and projected at 48 fps.[6] IMAX HD has also been used in film-based theme park attractions, including Disney'sSoarin' Over California.[7]
The proposedMaxivision 48 format ran35 mm film at 48 fps, but was never commercially deployed.[8]
Digital Cinema Initiatives has published a document outlining recommended practice for high frame rate digital cinema.[9] This document outlines the frame rates and resolutions that can be used in high frame rate digital theatrical presentations with currently available equipment.
In the case of cinema shot on film, as opposed to (whether analog or digital) video, HFR offers an additional benefit beyond temporal smoothness and motion blur. Especially for stationary subject matter, when shot with sufficientlyfast stock, the physically random repositioning offilm grains in each frame at higher rates effectivelyoversamples the image's spatial resolution beyond the minimum fineness of individual grains when viewed.
Peter Jackson'sThe Hobbit film series, beginning withThe Hobbit: An Unexpected Journey in December 2012, used a shooting and projection frame rate of 48 frames per second, becoming the first feature film with awide release to do so.[10] Its 2013 sequel,The Hobbit: The Desolation of Smaug and 2014 sequel,The Hobbit: The Battle of the Five Armies, followed suit. All films also have versions which are converted and projected at 24 fps.
In 2016,Ang Lee releasedBilly Lynn's Long Halftime Walk. UnlikeThe Hobbit trilogy, which used 48 frames per second, the picture shot and projected selected scenes in 120 frames per second, which is five times faster than the 24 frames per second standard used in Hollywood.[11] Lee's 2019Gemini Man was also shot and distributed in 120 frames per second.[12]
Other filmmakers who intend to use the high frame rate format includeJames Cameron in hisAvatar sequels[13][14] andAndy Serkis in his adaptation ofGeorge Orwell'sAnimal Farm.[15]
In early 2022, Cameron announced that HFR conversions for his previous films,Avatar andTitanic, were in the works.[16]
Avatar: The Way of Water released on December 16, 2022 with a dynamic frame rate. Some scenes are displayed up to 48 fps, while others are displayed in a more traditional, slower rate.[17]
Even when shot on film, frame rates higher than 24 fps and 30 fps are quite common inTV drama andin-game cinematics. Approximately 50 or 60 frames per second have been the standard in television and video equipment, broadcast, and storage standards since their inception. Support for native 120 fps content is a primary feature of newUltra-high-definition television standards such asATSC 3.0.
Some media players are capable of showing arbitrarily high framerates and almost all computers and smart devices can handle such formats as well. In recent years some televisions can take normal 24 fps videos and "upconvert" them to HFR content byinterpolating the motion of the picture, creating new computer-generated frames between each two key frames and running them at higher refresh rate. Similar computer programs allow for that as well but with higher precision and better quality as the computing power of the PC has grown, either real-time oroffline.
Filmmakers may originate their projects at 120, 240 or 300 fps so that it may be evenly pulled down to various multiple differing frame rates for distribution, such as 25, 30, 50, and 60 fps for video and 24, 48 or 60 fps for cinematic theater. The same is also done when creatingslow motion sequences and is sometimes referred to as "overcranking."[18]
Usually, cameras (including those in mobile phones) historically had two ways of encoding high framerate (or slow motion) video into the video file: thereal-time method and themenial method.