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1080i (also known as Full HD or BT.709) is a combination of frame resolution and scan type. 1080i is used in high-definition television (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 of each frame, then only the odd lines, are drawn alternately, so that only half the number of lines are ever updated at once. A related display resolution is 1080p, which also has 1080 lines of resolution; the "p" refers to progressive scan, which indicates that each full frame appears on the screen in sequence.
The term assumes a widescreen 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 1080i screen has a total of 2.1 megapixels (2.1 million pixels) and a temporal resolution of 50 or 60 interlaced fields per second. This format is used in the SMPTE 292M standard.
Within the designation "1080i", the i stands for interlaced scan. Each frame of 1080i video consists of two sequential fields of 1920 horizontal and 540 vertical pixels. 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. [1]
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 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.
The field rate of 1080i is typically 60 Hz (i.e., 60 fields per second) for countries that use or used System M (NTSC and Brazilian PAL-M) 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 or SECAM) 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, as in 1080i/30 and 1080i/25, likewise 480i/30 and 576i/25. [2] 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, 1080i is the preferred format for most broadcasters, with Warner Bros. Discovery, Paramount Global, and Comcast owned networks broadcasting in the format, along with most smaller broadcasters. Only Fox- and Disney-owned television networks, along with MLB Network and a few other cable networks, use 720p as the preferred format for their networks; A+E Networks 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 and former Belo Corporation stations owned by TEGNA, 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 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.
Interlaced video 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 enhances motion perception to the viewer, and reduces flicker by taking advantage of the phi phenomenon.
Progressive scanning is a format of displaying, storing, or transmitting moving images in which all the lines of each frame are drawn in sequence. This is in contrast to interlaced video used in traditional analog television systems where only the odd lines, then the even lines of each frame are drawn alternately, so that only half the number of actual image frames are used to produce video. The system was originally known as "sequential scanning" when it was used in the Baird 240 line television transmissions from Alexandra Palace, United Kingdom in 1936. It was also used in Baird's experimental transmissions using 30 lines in the 1920s. Progressive scanning became universally used in computer screens beginning in the early 21st century.
Advanced Television Systems Committee (ATSC) standards are an American set of standards for digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard and, like that standard, is used mostly in the United States, Mexico, Canada, South Korea and Trinidad & Tobago. Several former NTSC users, such as Japan, have not used ATSC during their digital television transition, because they adopted other systems such as ISDB developed by Japan, and DVB developed in Europe, for example.
Enhanced-definition television, or extended-definition television (EDTV) is a Consumer Electronics Association (CEA) marketing shorthand term for certain digital television (DTV) formats and devices. Specifically, this term defines an extension of the standard-definition television (SDTV) format that enables a clearer picture during high-motion scenes compared to previous iterations of SDTV, but not producing images as detailed as high-definition television (HDTV).
The display resolution or display modes of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT) displays, flat-panel displays and projection displays using fixed picture-element (pixel) arrays.
Deinterlacing is the process of converting interlaced video into a non-interlaced or progressive form. Interlaced video signals are commonly found in analog television, digital television (HDTV) when in the 1080i format, some DVD titles, and a smaller number of Blu-ray discs.
HD-MAC was a broadcast television standard proposed by the European Commission in 1986, as part of Eureka 95 project. It belongs to the MAC - Multiplexed Analogue Components standard family. It is an early attempt by the EEC to provide High-definition television (HDTV) in Europe. It is a complex mix of analogue signal, multiplexed with digital sound, and assistance data for decoding (DATV). The video signal was encoded with a modified D2-MAC encoder.
HDV is a format for recording of high-definition video on DV videocassette tape. The format was originally developed by JVC and supported by Sony, Canon, and Sharp. The four companies formed the HDV Consortium in September 2003.
480p is the shorthand name for a family of video display resolutions. The p stands for progressive scan, i.e. non-interlaced. The 480 denotes a vertical resolution of 480 pixels, usually with a horizontal resolution of 640 pixels and 4:3 aspect ratio or a horizontal resolution of 854 pixels for an approximate 16:9 aspect ratio. Since a pixel count must be a whole number, in Wide VGA displays it is generally rounded up to 854 to ensure inclusion of the entire image. The frames are displayed progressively as opposed to interlaced. 480p was used for many early plasma televisions. Standard definition has always been a 4:3 aspect ratio with a pixel resolution of 720 × 480 at 60 Hz for NTSC regions, and 720 or 768 × 576 for PAL regions. However, standard definition defines a 15.7k Hz horizontal scanrate, which means that interlacing has to be used for those resolution modes. The lowercase letter "p" in 480p stands for progressive, so the two must not be confused.
720p is a progressive HD signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HD (1.78:1). All major HD broadcasting standards include a 720p format, which has a resolution of 1280×720p.
480i is the video mode used for standard-definition digital video in the Caribbean, Japan, South Korea, Taiwan, Philippines, Western Sahara, and most of the Americas. The other common standard definition digital standard, used in the rest of the world, is 576i.
576p is the shorthand name for a video display resolution. The p stands for progressive scan, i.e. non-interlaced, the 576 for a vertical resolution of 576 pixels. Usually it corresponds to a digital video mode with a 4:3 anamorphic resolution of 720x576 and a frame rate of 25 frames per second (576p25), and thus using the same bandwidth and carrying the same amount of pixel data as 576i, but other resolutions and frame rates are possible.
High-definition video is video of higher resolution and quality than standard-definition. While there is no standardized meaning for high-definition, generally any video image with considerably more than 480 vertical scan lines or 576 vertical lines (Europe) is considered high-definition. 480 scan lines is generally the minimum even though the majority of systems greatly exceed that. Images of standard resolution captured at rates faster than normal, by a high-speed camera may be considered high-definition in some contexts. Some television series shot on high-definition video are made to look as if they have been shot on film, a technique which is often known as filmizing.
1080p is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen vertically; the p stands for progressive scan, i.e. non-interlaced. The term usually assumes a widescreen aspect ratio of 16:9, implying a resolution of 2.1 megapixels. It is often marketed as Full HD or FHD, to contrast 1080p with 720p resolution screens. Although 1080p is sometimes informally referred to as 2K, these terms reflect two distinct technical standards, with differences including resolution and aspect ratio.
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 that the content of one field will be used on all of the odd-numbered lines on the screen and the other field will be displayed on the even lines. Converting fields to a still frame image requires a process called deinterlacing, in which the missing lines are duplicated or interpolated to recreate the information that would have been contained in the discarded field. Since each field contains only half of the information of a full frame, however, deinterlaced images do not have the resolution of a full frame.
HD Lite is the re-transmission of a particular HDTV channel at reduced picture quality compared to the source.
High-definition television describes a television 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 refers to the generation following standard-definition television (SDTV), often abbreviated to HDTV or HD-TV. It is the current de facto standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television and Blu-ray Discs.
4K resolution refers to a horizontal display resolution of approximately 4,000 pixels. Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 3840 × 2160 is the dominant 4K standard, whereas the movie projection industry uses 4096 × 2160.