1080i (also known as Full HD or
BT.709
Rec. 709, also known as Rec.709, BT.709, and ITU 709, is a standard developed by ITU-R for image encoding and signal characteristics of high-definition television.
The most recent version is BT.709-6 released in 2015. BT.709-6 defines the P ...
) is a combination of
frame
A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent.
Frame and FRAME may also refer to:
Physical objects
In building construction
*Framing (con ...
resolution
Resolution(s) may refer to:
Common meanings
* Resolution (debate), the statement which is debated in policy debate
* Resolution (law), a written motion adopted by a deliberative body
* New Year's resolution, a commitment that an individual mak ...
and scan type. 1080i is used in
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 ...
(HDTV) and
high-definition video. The number "1080" refers to the number of horizontal lines on the screen. The "i" is an abbreviation for
"interlaced"; this indicates that only the even lines, then the odd lines of each frame (each image called a video field) are drawn alternately, so that only half the number of actual image frames are used to produce video. A related display resolution is
1080p, which also has 1080 lines of resolution; the "p" refers to
progressive scan, which indicates that the lines of resolution for each frame are "drawn" on the screen in sequence.
The term assumes a
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 ...
aspect ratio of
16:9 (a rectangular TV that is wider than it is tall), so the 1080 lines of vertical resolution implies 1920 columns of horizontal resolution, or 1920 pixels × 1080 lines. A 1920 pixels × 1080 lines screen has a total of 2.1
megapixels
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 ...
(2.1 million pixels) and a temporal resolution of 50 or 60
interlaced
Interlaced video (also known as interlaced scan) is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. This ...
fields per second. This format is used in the
SMPTE 292M SMPTE 292 is a digital video transmission line standard published by the Society of Motion Picture and Television Engineers (SMPTE). This technical standard is usually referred to as HD-SDI; it is part of a family of standards that define a Serial ...
standard.
Broadcast standard
Within the designation "1080i", the ''i'' stands for
interlaced scan
Interlaced video (also known as interlaced scan) is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. This ...
. A frame of 1080i video consists of two sequential
fields
Fields may refer to:
Music
* Fields (band), an indie rock band formed in 2006
* Fields (progressive rock band), a progressive rock band formed in 1971
* ''Fields'' (album), an LP by Swedish-based indie rock band Junip (2010)
* "Fields", a song b ...
of 1920 horizontal and 540 vertical
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 ...
s. The first field consists of all even-numbered TV lines and the second all odd numbered lines. Consequently, the horizontal lines of pixels in each field are captured and displayed with a one-line vertical gap between them, so the lines of the next field can be interlaced between them, resulting in 1080 total lines.
1080i differs from
1080p, where the ''p'' stands for
progressive scan, where all lines in a frame are captured at the same time. In ''native'' or ''pure'' 1080i, the two fields of a frame correspond to different instants (points in time), so motion portrayal is good (50 or 60 motion phases/second). This is true for
interlaced video
Interlaced video (also known as interlaced scan) is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. Thi ...
in general and can be easily observed in still images taken of fast motion scenes. However, when 1080p material is captured at 25 or 30 ''frames''/second, it is converted to 1080i at 50 or 60 ''fields''/second, respectively, for processing or broadcasting. In this situation both fields in a frame do correspond to the same instant. The field-to-instant relation is somewhat more complex for the case of 1080p at 24 ''frames''/second converted to 1080i at 60 ''fields''/second; see
telecine
Telecine ( or ) is the process of transferring film into video and is performed in a color suite. The term is also used to refer to the equipment used in the post-production process.
Telecine enables a motion picture, captured originally on fi ...
.
The
field rate
The refresh rate (or "vertical refresh rate", "vertical scan rate", terminology originating with the cathode ray tubes) is the number of times per second that a Raster scan, raster-based display device displays a new image. This is independent fro ...
of 1080i is typically 60 Hz (i.e., 60 fields per second) for countries that use or used
System M (
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 ...
and Brazilian
PAL-M
PAL-M is the analogue TV system used in Brazil since 19 February 1972. At that time, Brazil was the first South American country to broadcast in colour. Colour TV broadcast began on 19 February 1972, when the TV networks Globo and Bandeirantes t ...
) as analog television system with 60 fields/sec (such as United States, Canada, Mexico, Japan, South Korea, Taiwan and Philippines), or 50 Hz for regions that use or used
625-lines (
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 ...
or
SECAM
SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''color sequential with memory''), is an analog color television system that was used in France, some parts of Europe and Africa, and Russia. It was one of th ...
) television system with 50 fields/sec (such as most of Europe, most of Africa, China, India, Australia, New Zealand, Middle East, and others). Both field rates can be carried by major digital television broadcast formats such as ATSC, DVB, and ISDB-T International. The frame rate can be implied by the context, while the field rate is generally specified after the letter i, such as "1080i60". In this case 1080i60 refers to 60 fields per second. The
European Broadcasting Union (EBU) prefers to use the resolution and ''frame rate'' (not field rate) separated by a
slash
Slash may refer to:
* Slash (punctuation), the "/" character
Arts and entertainment Fictional characters
* Slash (Marvel Comics)
* Slash (''Teenage Mutant Ninja Turtles'')
Music
* Harry Slash & The Slashtones, an American rock band
* Nash ...
, as in ''1080i/30'' and ''1080i/25'', likewise 480i/30 and 576i/25.
["High Definition (HD) Image Formats for Television Production," EBU-TECH 3299, EBU.UER, Geneva, January 2010, page 7] Resolutions of 1080i60 or 1080i50 often refers to 1080i/30 or 1080i/25 in EBU notation.
1080i is directly compatible with some
CRT HDTVs on which it can be displayed natively in interlaced form, but for display on
progressive-scan—e.g., most new LCD and plasma
TVs, it must be deinterlaced. Depending on the television's video processing capabilities, the resulting video quality may vary, but may not necessarily suffer. For example, film material at 25fps may be deinterlaced from 1080i50 to restore a full 1080p resolution at the original frame rate without any loss. Preferably video material with 50 or 60 motion phases/second is to be converted to 50p or 60p before display.
Worldwide, most HD channels on satellite and cable broadcast in 1080i. In the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, 1080i is the preferred format for most broadcasters, with
Warner Bros. Discovery
Warner Bros. Discovery, Inc. (WBD) is an American multinational mass media and entertainment conglomerate headquartered at 230 Park Avenue South in New York City. It was formed after the spin-off of WarnerMedia by AT&T, and its merger with Di ...
,
Paramount Global
Paramount Global ( doing business as Paramount) is an American multinational mass media and entertainment conglomerate owned and operated by National Amusements (79.4%) and headquartered at One Astor Plaza in Midtown Manhattan, New York. ...
, and
Comcast owned networks broadcasting in the format, along with most smaller broadcasters. Only
Fox
Foxes are small to medium-sized, omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull, upright, triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or ''brush'').
Twelve sp ...
- and
Disney
The Walt Disney Company, commonly known as Disney (), is an American multinational mass media and entertainment conglomerate headquartered at the Walt Disney Studios complex in Burbank, California. Disney was originally founded on October ...
-owned television networks, along with
MLB Network
The MLB Network is an American television sports channel dedicated to baseball. It is primarily owned by Major League Baseball, with Warner Bros. Discovery through its sports unit, Comcast's NBC Sports Group, Charter Communications, and Cox C ...
and a few other cable networks, use
720p
720p (1280×720 px; also called HD ready, standard HD or just HD) is a progressive HDTV signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcast ...
as the preferred format for their networks;
A+E Networks
A&E Networks (stylized as A+E NETWORKS) is an American multinational broadcasting company that is a 50–50 joint venture between Hearst Communications and The Walt Disney Company through its General Entertainment Content division. The company ...
channels converted from 720p to 1080i sometime in 2013 due to acquired networks already transmitting in the 1080i format. Many ABC affiliates owned by
Hearst Television
Hearst Television, Inc. (formerly Hearst-Argyle Television) is a broadcasting company in the United States owned by Hearst Communications. From 1998 to mid-2009, the company traded its common stock on the New York Stock Exchange under the symbol ...
and former
Belo Corporation
Belo Corporation was a Dallas-based media company that owned 20 commercial broadcasting television stations and three regional 24-hour cable news television channels. The company was previously known as A. H. Belo Corporation after one of the ...
stations owned by
TEGNA
Tegna Inc. (stylized in all caps as TEGNA) is an American publicly traded broadcast, digital media and marketing services company headquartered in Tysons Corner, Virginia. It was created on June 29, 2015, when the Gannett Company split into t ...
, along with some individual affiliates of those three networks, air their signals in 1080i and upscale network programming for master control and transmission purposes, as most syndicated programming and advertising is produced and distributed in 1080i/p, removing a downscaling step to 720p. This also allows local newscasts on these ABC affiliates to be produced in the higher resolution (especially for
weather forecasting
Weather forecasting is the application of science and technology to predict the conditions of the atmosphere for a given location and time. People have attempted to predict the weather informally for millennia and formally since the 19th cent ...
presentation purposes for map clarity) to match the picture quality of their 1080i competitors.
Some cameras and broadcast systems that use 1080 vertical lines per frame do not actually use the full 1920 pixels of a nominal 1080i picture for image capture and encoding. Common subsampling ratios include 3/4 (resulting in 1440x1080i frame resolution) and 1/2 (resulting in 960x1080i frame resolution). Where used, the lower horizontal resolution is scaled to capture or display a full-sized picture. Using half horizontal resolution and only one field of each frame (possibly with added anti-alias filtering or progressive capture) results in the format known as qHD, which has frame resolution 960x540 and 30 or 25 frames per second. Due to the chosen 16x16 pixel size for a compressed video packet known as a ''macroblock'' as used in ITU H.261 to H.264 video standards, a 1080-line video must be encoded as 1088 lines and cropped to 1080 by the de-compressor. The 720-line video format divides perfectly by 16 and therefore does not require any lines to be wasted.
See also
*
Field (video)
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 ...
*
High-definition television in the United States
High-definition television (HDTV) in the United States was introduced in 1998 and has since become increasingly popular and dominant in the television market. Hundreds of HD channels are available in millions of homes and businesses both terrest ...
*
Interlaced video
Interlaced video (also known as interlaced scan) is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. Thi ...
*
List of common resolutions
This article lists computer monitor screen resolutions that are defined by standards or in common use. Most of them use certain preferred numbers.
Computer graphics
; Pixel aspect ratio (PAR): The horizontal to vertical ratio of each pixel.
; ...
*
Sony HDVS
Sony HDVS is a range of high-definition video equipment developed in the 1980s to support an early analog high-definition television system (used in multiple sub-Nyquist sampling encoding (MUSE) broadcasts) thought to be the broadcast television ...
Wideband Analog Video
*
Telecine
Telecine ( or ) is the process of transferring film into video and is performed in a color suite. The term is also used to refer to the equipment used in the post-production process.
Telecine enables a motion picture, captured originally on fi ...
* Other common resolutions:
4320p 2160p 1080p 720p
720p (1280×720 px; also called HD ready, standard HD or just HD) is a progressive HDTV signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcast ...
576p 576i 480p 480i 360p 240p
References
External links
High Definition (HD) Image Formats for Television Production(
EBU technical publication)
{{Video formats
Video formats
Television terminology