Jerkiness, sometimes called strobing or choppy, describes the perception of individual still images in a motion picture. 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 and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

interprets the sequence as continuous motion. However, some technologies cannot process or carry data fast enough for sufficiently high frame rates. For example, viewing motion pictures by

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

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

cinematography Cinematography (from ancient Greek κίνημα, ''kìnema'' "movement" and γράφειν, ''gràphein'' "to write") is the art of motion picture (and more recently, electronic video camera) photography. Cinematographers use a lens to foc ...

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

Television screen A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...

s refresh at even higher frequencies.

PAL Phase Alternating Line (PAL) is a colour encoding system for analogue 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 large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

) refresh at 25 or 50 (

HDTV 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 ...

) frames per second.

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 ...

television displays (the standard in North America) refresh at 29.97 frames per second. Animated cartoon 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 sequenti ...

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 commerci ...

features. 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 systems 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 image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the ...

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

See also