Jerkiness (sometimes called strobing or choppy footage) describes the perception of individual still images while watching a

motion picture A film, also known as a movie or motion picture, is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, emotions, or atmosphere through the use of moving images that are generally, since ...

Description

Motion pictures are made from still images shown in rapid sequence. Provided there is sufficient continuity between the images and provided the sequence is shown fast enough, the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

interprets the sequence as continuous motion. However, some technologies cannot process or carry data fast enough for sufficiently high

frame rate Frame rate, most commonly expressed in frame/s, or FPS, is typically the frequency (rate) at which consecutive images (Film frame, frames) are captured or displayed. This definition applies to film and video cameras, computer animation, and moti ...

s. For example, viewing motion pictures by

Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...

connection generally necessitates a greatly reduced frame rate, making jerkiness clearly apparent. In conventional

cinematography Cinematography () is the art of motion picture (and more recently, electronic video camera) photography. Cinematographers use a lens (optics), lens to focus reflected light from objects into a real image that is transferred to some image sen ...

, the images are filmed and displayed at 24 frames per second, at which speed jerkiness is not normally discernible. Television screens refresh at even higher

frequencies Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

PAL Phase Alternating Line (PAL) is a color encoding system for analog television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

and SÉCAM television (the standards in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

) refresh at 25 or 50 (

HDTV High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it ref ...

) frames per second.

NTSC NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170. In 1953, a second ...

television displays (the standard in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

) refresh at 29.97 frames per second.

Animated cartoon Animation is a filmmaking technique whereby still images are manipulated to create moving images. In traditional animation, images are drawn or painted by hand on transparent celluloid sheets to be photographed and exhibited on film. Animati ...

films are typically made at reduced frame rates (accomplished by shooting several

film frame In filmmaking, video production, animation, and related fields, a frame is one of the many '' still images'' which compose the complete ''moving picture''. The term is derived from the historical development of film stock, in which the sequentia ...

s of the individual drawings) so as to limit production costs, with the result that jerkiness tends to be apparent, especially on older

limited animation Limited animation is a process in the overall technique of traditional animation that reuses frames of character animation. Early history The use of budget-cutting and time-saving animation measures in animation dates back to the earliest commerc ...

features.

Other uses

Strobing can also refer to cross colour and Moiré patterning. Cross colour refers to when any high frequency luminance content of the picture, close to the TV system's colour sub-carrier frequency, is interpreted by the analogue receiver's decoder as colour information. Moiré patterning is where an interference pattern is produced by fine scene detail beating with the line (or even

pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...

) structure of the device used to analyse or display the scene.

Description

Other uses

References

See also