SIGMA is an electronic
verification service offered by
Nielsen Media Research
Nielsen Media Research (NMR) is an American firm that measures media audiences, including television, radio, theatre, films (via the AMC Theatres MAP program), and newspapers. Headquartered in New York City, it is best known for the Nielsen rat ...
and is generally used for
commercials
A television advertisement (also called a commercial, spot, break, advert, or ad) is a span of television programming produced and paid for by an organization. It conveys a message promoting, and aiming to market, a product, service or idea. ...
,
infomercials
An infomercial is a form of television commercial that resembles regular TV programming yet is intended to promote or sell a product, service or idea. It generally includes a toll-free telephone number or website. Most often used as a form of di ...
,
video
Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, whi ...
news releases,
public service announcements,
satellite media tours, and
electronic press kits.
It operates by encoding the SIGMA
encoder ID, date of encoding, and time of encoding in lines 20 and 22 of the video signal, which is outside of the area displayed on a normal
television
Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...
screen (this is similar to how
closed captioning
Closed captioning (CC) is the process of displaying text on a television, video screen, or other visual display to provide additional or interpretive information, where the viewer is given the choice of whether the text is displayed. Closed cap ...
is transmitted).
On a professional
video monitor
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 signa ...
with
underscan capability activated or a computer display of the entire
video 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 ...
, the SIGMA data will look like small, moving white lines at the top of the frame. Nielsen provides overnight reports of
airplay
Airplay is how frequently a song is being played through broadcasting on radio stations. A song which is being played several times every day (spins) would have a significant amount of airplay. Music which became very popular on jukeboxes, in n ...
in all
television markets in the country.
Television technology
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