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filmmaking Filmmaking (film production) is the process by which a motion picture is produced. Filmmaking involves a number of complex and discrete stages, starting with an initial story, idea, or commission. It then continues through screenwriting, casti ...
,
video production Video production is the process of producing video content for video. It is the equivalent of filmmaking, but with video recorded either as analog signals on videotape, digitally in video tape or as computer files stored on optical discs, hard dri ...
,
animation Animation is a method by which still figures are manipulated to appear as moving images. In traditional animation, images are drawn or painted by hand on transparent celluloid sheets to be photographed and exhibited on film. Today, most ani ...
, and related fields, a frame is one of the many ''
still image An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...
s'' which compose the complete ''
moving picture A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmospher ...
''. The term is derived from the historical development of
film stock Film stock is an analog medium that is used for recording motion pictures or animation. It is recorded on by a movie camera, developed, edited, and projected onto a screen using a movie projector. It is a strip or sheet of transparent ...
, in which the sequentially recorded single images look like a framed picture when examined individually. The term may also be used more generally as a noun or verb to refer to the edges of the image as seen in a camera viewfinder or projected on a screen. Thus, the camera operator can be said to keep a car in frame by panning with it as it speeds past.


Overview

When the moving picture is displayed, each frame is flashed on a screen for a short time (nowadays, usually 1/24, 1/25 or 1/30 of a second) and then immediately replaced by the next one.
Persistence of vision Persistence of vision traditionally refers to the optical illusion that occurs when visual perception of an object does not cease for some time after the rays of light proceeding from it have ceased to enter the eye. The illusion has also been d ...
blends the frames together, producing the
illusion An illusion is a distortion of the senses, which can reveal how the mind normally organizes and interprets sensory stimulation. Although illusions distort the human perception of reality, they are generally shared by most people. Illusions may o ...
of a moving image. The frame is also sometimes used as a unit of time, so that a momentary event might be said to last six frames, the actual duration of which depends on the
frame rate Frame rate (expressed in or FPS) is the frequency (rate) at which consecutive images (frames) are captured or displayed. The term applies equally to film and video cameras, computer graphics, and motion capture systems. Frame rate may also be c ...
of the system, which varies according to the video or film standard in use. In North America and Japan, 30 frames per second (fps) is the broadcast standard, with 24 frames/s now common in production for high-definition video shot to look like film. In much of the rest of the world, 25 frames/s is standard. In systems historically based on
NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
standards, for reasons originally related to the Chromilog NTSC TV systems, the exact frame rate is actually (3579545 / 227.5) / 525 = 29.97002616 fps. This leads to many synchronization problems which are unknown outside the NTSC world, and also brings about hacks such as drop-frame timecode. In film projection, 24 fps is the normal, except in some special venue systems, such as
IMAX IMAX is a proprietary system of high-resolution cameras, film formats, film projectors, and theaters known for having very large screens with a tall aspect ratio (approximately either 1.43:1 or 1.90:1) and steep stadium seating. Graem ...
,
Showscan Showscan is a cinematic process developed by Douglas Trumbull that uses 70mm film photographed and projected at 60 frames per second, 2.5 times the standard speed of movie film. History Trumbull first came to the public's attention for his work o ...
and Iwerks 70, where 30, 48 or even 60 frame/s have been used. Silent films and 8 mm amateur movies used 16 or 18 frame/s.


Physical film frames

In a strip of movie film, individual frames are separated by
frame line A frame line is the unused space that separates two adjacent images, or film frames, on the release print of a motion picture. They can vary in width; a 35mm film with a 1.85:1 hard matte has a frame line approximately high, whereas both a f ...
s. Normally, 24 frames are needed for one
second The second (symbol: s) is the unit of time in the International System of Units (SI), historically defined as of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds e ...
of film. In ordinary filming, the frames are photographed automatically, one after the other, in a
movie camera A movie camera (also known as a film camera and cine-camera) is a type of photographic camera that rapidly takes a sequence of photographs, either on an image sensor or onto film stock, in order to produce a moving image to project onto a movie sc ...
. In
special effects Special effects (often abbreviated as SFX, F/X or simply FX) are illusions or visual tricks used in the theatre, film, television, video game, amusement park and simulator industries to simulate the imagined events in a story or virtual w ...
or
animation Animation is a method by which still figures are manipulated to appear as moving images. In traditional animation, images are drawn or painted by hand on transparent celluloid sheets to be photographed and exhibited on film. Today, most ani ...
filming, the frames are often shot one at a time. The size of a film frame varies, depending on the still film format or the motion picture film format. In the smallest 8 mm amateur format for motion pictures film, it is only about 4.8 by 3.5 mm, while an
IMAX IMAX is a proprietary system of high-resolution cameras, film formats, film projectors, and theaters known for having very large screens with a tall aspect ratio (approximately either 1.43:1 or 1.90:1) and steep stadium seating. Graem ...
frame is as large as 69.6 by 48.5 mm. The larger the frame size is in relation to the size of the
projection screen A projection screen is an installation consisting of a surface and a support structure used for displaying a projected image for the view of an audience. Projection screens may be permanently installed, as in a movie theater; painted on the w ...
, the sharper the image will appear. The size of the film frame of
motion picture film Film stock is an analog medium that is used for recording motion pictures or animation. It is recorded on by a movie camera, developed, edited, and projected onto a screen using a movie projector. It is a strip or sheet of transparent p ...
also depends on the location of the holes, the size of the holes, the shape of the holes. and the location and type of sound stripe. The most common film format, 35 mm, has a frame size of 36 by 24 mm when used in a still 35 mm camera where the film moves horizontally, but the frame size varies when used for motion picture where the film moves vertically (with the exception of
VistaVision VistaVision is a higher resolution, widescreen variant of the 35 mm motion picture film format which was created by engineers at Paramount Pictures in 1954. Paramount never used anamorphic processes such as 2.55: 1, CinemaScope but refin ...
and
Technirama __NOTOC__ Technirama is a screen process that has been used by some film production houses as an alternative to CinemaScope. It was first used in 1957 but fell into disuse in the mid-1960s. The process was invented by Technicolor and is an anamor ...
where the film moves horizontally). Using a
4-perf pulldown Negative pulldown is the manner in which an image is exposed on a film stock, described in the number of film perforations spanned by an individual frame. It can also describe the orientation of the image on the negative, whether it is captured h ...
, there are exactly 16 frames in one foot of 35 mm film, leading to film frames sometimes being counted in terms of "
feet and frames The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...
". The maximum frame size is 18 by 24 mm, (silent/full aperture), but this is significantly reduced by the application of sound track(s). A system called KeyKode is often used to identify specific physical film frames in a production.


Video frames

Historically, video frames were represented as
analog waveform An analog signal or analogue signal (see spelling differences) is any continuous signal representing some other quantity, i.e., ''analogous'' to another quantity. For example, in an analog audio signal, the instantaneous signal voltage varies c ...
s in which varying voltages represented the intensity of light in an analog
raster scan A raster scan, or raster scanning, is the rectangular pattern of image capture and reconstruction in television. By analogy, the term is used for raster graphics, the pattern of image storage and transmission used in most computer bitmap image s ...
across the screen. Analog
blanking interval In analog video, blanking occurs between horizontal lines and between frames. In raster scan equipment, an image is built up by scanning an electron beam from left to right across a screen to produce a visible trace of one scan line, reducing the ...
s separated video frames in the same way that frame lines did in film. For historical reasons, most systems used an interlaced scan system in which the frame typically consisted of two
video field In video, a field is one of the many still images which are displayed sequentially to create the impression of motion on the screen. Two fields comprise one video frame. When the fields are displayed on a video monitor they are "interlaced" so th ...
s sampled over two slightly different periods of time. This meant that a single video frame was usually not a good still picture of the scene, unless the scene being shot was completely still. With the dominance of digital technology, modern video systems now represent the video frame as a rectangular raster of
pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the sm ...
s, either in an RGB color space or a color space such as YCbCr, and the analog waveform is typically found nowhere other than in legacy I/O devices. Standards for the digital video frame raster include Rec. 601 for
standard-definition television Standard-definition television (SDTV, SD, often shortened to standard definition) is a television system which uses a resolution that is not considered to be either high or enhanced definition. "Standard" refers to it being the prevailing s ...
and Rec. 709 for
high-definition television High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
. Video frames are typically identified using
SMPTE time code SMPTE timecode ( or ) is a set of cooperating standards to label individual frames of video or film with a timecode. The system is defined by the Society of Motion Picture and Television Engineers in the SMPTE 12M specification. SMPTE revised t ...
.


Line and resolution

The frame is composed of picture elements just like a chess board. Each horizontal set of picture elements is known as a
line Line most often refers to: * Line (geometry), object with zero thickness and curvature that stretches to infinity * Telephone line, a single-user circuit on a telephone communication system Line, lines, The Line, or LINE may also refer to: Art ...
. The picture elements in a line are transmitted as
sine In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is oppo ...
signals where a pair of dots, one dark and one light can be represented by a single sine. The product of the number of lines and the number of maximum sine signals per line is known as the total resolution of the frame. The higher the resolution the more faithful the displayed image is to the original image. But higher resolution introduces technical problems and extra cost. So a compromise should be reached in system designs both for satisfactory image quality and affordable price.


Viewing distance

The key parameter to determine the lowest resolution still satisfactory to viewers is the viewing distance, i.e. the distance between the eyes and the monitor. The total resolution is inversely proportional to the square of the distance. If d is the distance, r is the required minimum resolution and k is the proportionality constant which depends on the size of the monitor; : r = k^2 \cdot \frac Since the number of lines is approximately proportional to the resolution per line, the above relation can also be written as : n = k \cdot \frac where n is the number of lines. That means that the required resolution is proportional to the height of the monitor and inversely proportional to the viewing distance.


Moving picture

In moving picture (TV) the number of frames scanned per second is known as the frame rate. The higher the frame rate, the better the sense of motion. But again, increasing the frame rate introduces technical difficulties. So the frame rate is fixed at 25 ( System B/G) or 29.97 ( System M). To increase the sense of motion it is customary to scan the very same frame in two consecutive phases. In each phase only half of the lines are scanned; only the lines with odd numbers in the first phase and only the lines with even numbers in the second phase. Each scan is known as a
field Field may refer to: Expanses of open ground * Field (agriculture), an area of land used for agricultural purposes * Airfield, an aerodrome that lacks the infrastructure of an airport * Battlefield * Lawn, an area of mowed grass * Meadow, a grass ...
. So the field rate is two times the frame rate.


Example (System B)

In system B the number of lines is 625 and the frame rate is 25. The maximum video bandwidth is 5 MHz. The maximum number of sine signals the system is theorically capable of transmitting is given as follows: The system is able to transmit 5 000 000 sine signals in a second. Since the frame rate is 25, the maximum number of sine signals per frame is 200 000. Dividing this number by the number of lines gives the maximum number of sine signals in a line which is 320. (Actually about 19% of each line is devoted to auxiliary services. So the number of maximum useful sine signals is about 260.)


Still frame

A still frame is a single static
image An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...
taken from a
film A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...
or
video Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) sy ...
, which are kinetic (moving) images. Still frames are also called freeze frame, video prompt, preview or misleadingly
thumbnail Thumbnails are reduced-size versions of pictures or videos, used to help in recognizing and organizing them, serving the same role for images as a normal text index does for words. In the age of digital images, visual search engines and image- ...
,
keyframe In animation and filmmaking, a key frame (or keyframe) is a drawing or shot that defines the starting and ending points of a smooth transition. These are called ''frames'' because their position in time is measured in frames on a strip of film ...
, poster frame, or screen shot/grab/capture/dump. Freeze frames are widely used on video platforms and in video galleries, to show viewers a preview or a teaser. Many video platforms have a standard to display a frame from mid-time of the video. Some platforms offer the option to choose a different frame individually. Video and film artists sometimes use still frames within the video/film to achieve
special effect Special effects (often abbreviated as SFX, F/X or simply FX) are illusions or visual tricks used in the theatre, film, television, video game, amusement park and simulator industries to simulate the imagined events in a story or virtual w ...
s, like
freeze-frame shot In film and video, a freeze frame is when a single frame of content shows repeatedly on the screen—"freezing" the action. This can be done in the content itself, by printing (on film) or recording (on video) multiple copies of the same source fr ...
s or still motion.


Investigations

For criminal investigations it has become a frequent use to publish still frames from
surveillance Surveillance is the monitoring of behavior, many activities, or information for the purpose of information gathering, influencing, managing or directing. This can include observation from a distance by means of electronic equipment, such as ...
videos in order to identify suspect persons and to find more witnesses. Videos of the J.F. Kennedy assassination have been often discussed frame-by-frame for various interpretations. For medical diagnostics it is very useful to watch still frames of
Magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wav ...
videos.Lister Hill National Center for Biomedical Communications
A classic diagnosis with a new ‘spin’
retrieved 29 June 2014


Fourth wall usage

Some humor in animation is based on the
fourth wall The fourth wall is a performance convention in which an invisible, imaginary wall separates actors from the audience. While the audience can see through this ''wall'', the convention assumes the actors act as if they cannot. From the 16th cen ...
aspect of the film frame itself, with some animation showing characters leaving what is assumed to be the edge of the film or the film malfunctioning. This latter one is used often in films as well. This hearkens back to some early cartoons, where characters were aware that they were in a cartoon, specifically that they could look at the credits and be aware of something that isn't part of the story as presented. These jokes include: * Split frames – Where the ''fourth wall'' is broken by two frames, the lower half of the previous frame and the upper part of the next frame, showing at once, usually showing
frame line A frame line is the unused space that separates two adjacent images, or film frames, on the release print of a motion picture. They can vary in width; a 35mm film with a 1.85:1 hard matte has a frame line approximately high, whereas both a f ...
s, with jokes involving them including a character crossing the frame itself. * ''Film break'' – A famous form of the joke, where the film either snaps or is deliberately broken, with often the ''fourth wall'' coming into play during this period when, rightfully, there should be nothing on screen. * ''Gate hair'' – A famous form of joke where the animator intentionally places fake "gate hairs" within the frame, which one of the animated characters plucks and removes from the frame. * Editorial marks – Where those marks which an editor would normally employ on a "work print" to indicate the intended presence of a fade or a dissolve or a "wipe" to the SFX department are animated, and the film follows suit, or doesn't, depending upon the intended effect. * Cue marks – Where those marks, usually circular for non-Technicolor titles and "serrated" for Technicolor titles to indicate a reel changeover are animated for a humorous effect. This could also be employed for the famous "false ending" effect, employed even today in popular songs. For ''
Inglourious Basterds ''Inglourious Basterds'' is a 2009 war film written and directed by Quentin Tarantino, starring Brad Pitt, Christoph Waltz, Michael Fassbender, Eli Roth, Diane Kruger, Daniel Brühl, Til Schweiger and Mélanie Laurent. The film tells an altern ...
'', the cue marks for the reel changes of the ''Nation's Pride'' pseudo-documentary employed exceptionally large scribed circles with a large "X" scribed within it—marks which would never be utilized in actual editorial practice (motor and changeover cue marks are supposed to be clearly visible to the projectionist, but not obvious to the audience). * Exiting the frame – This joke, an extension of the split frames joke, has characters depart from the sides of the frame, sometimes finding themselves falling out of the cartoon entirely.


See also

*
Akinetopsia Akinetopsia (Greek: a for "without", kine for "to move" and opsia for "seeing"), also known as cerebral akinetopsia or motion blindness, is a term introduced by Semir Zeki to describe an extremely rare neuropsychological disorder, having only been ...
(motion blindness) *
Aspect ratio (image) The aspect ratio of an image is the ratio of its width to its height, and is expressed with two numbers separated by a colon, such as ''16:9'', sixteen-to-nine. For the ''x'':''y'' aspect ratio, the image is ''x'' units wide and ''y'' units high ...
* Freeze frame (disambiguation) * Freeze frame television * Film grammar *
Frame rate Frame rate (expressed in or FPS) is the frequency (rate) at which consecutive images (frames) are captured or displayed. The term applies equally to film and video cameras, computer graphics, and motion capture systems. Frame rate may also be c ...
*
Frame grabber A frame grabber is an electronic device that captures (i.e., "grabs") individual, digital still frames from an analog video signal or a digital video stream. It is usually employed as a component of a computer vision system, in which video frames ...
*
Key frame In animation and filmmaking, a key frame (or keyframe) is a drawing or shot that defines the starting and ending points of a smooth transition. These are called ''frames'' because their position in time is measured in frames on a strip of film ...
*
List of film formats This list of motion picture film formats catalogues formats developed for shooting or viewing motion pictures A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art t ...
*
Shot (filmmaking) In filmmaking and video production, a shot is a series of frames that runs for an uninterrupted period of time. Film shots are an essential aspect of a movie where angles, transitions and cuts are used to further express emotion, ideas and mo ...
*
Slow motion Slow motion (commonly abbreviated as slo-mo or slow-mo) is an effect in film-making whereby time appears to be slowed down. It was invented by the Austrian priest August Musger in the early 20th century. This can be accomplished through the use ...
*
Thumbshot {{Wiktionary Thumbshots are screenshots of online documents such as web page in small thumbnail sizes. Thumbshots help users to visualize web sites or preview links before clicking. The dimension of a thumbshot image (usually under 120 pixels in w ...
*
Widescreen Widescreen images are displayed within a set of aspect ratios (relationship of image width to height) used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ratio greater than t ...


Notes


References


External links


The image areas on a 35 mm film frame
{{Authority control Film formats Film and video terminology Articles containing video clips Television technology