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1080i is a term used in high-definition television (HDTV) and video display technology. It means a video mode with 1080 lines of vertical resolution. The "i" stands for interlaced scanning method. This format was once a standard in HDTV. It was particularly used for broadcast television. This is because it can deliver high-resolution images without needing excessive bandwidth. This format is used in the SMPTE 292M standard.
The number "1080" in 1080i refers to the number of horizontal lines that make up the vertical resolution of the display. Each of these lines contributes to the overall detail and clarity of the image. The letter "i" stands for interlaced. This is a technique where the image is not displayed all at once. Instead, the frame is split into two fields. One field contains the odd-numbered lines, and the other field contains the even-numbered lines. These fields are displayed in rapid succession, giving the appearance of a full image to the human eye. The interlacing technique was developed to improve the motion portrayal of images without doubling the required bandwidth. This is particularly useful in broadcasting, where bandwidth efficiency is crucial. The frame rate is typically 50 or 60 fields per second, depending on the region. This effectively means 25 or 30 frames per second when the fields are combined. [1]
A key difference between 1080i and 1080p is how the lines of resolution are displayed. Both offer 1920x1080 pixels, but the display method is different. In 1080p, the "p" stands for progressive scan. Each frame is drawn line by line, from top to bottom, creating a complete image in a single pass. This results in a sharper and more stable picture, especially in fast-moving scenes. On the other hand, 1080i uses an interlaced method. The two fields that make up a frame are captured at slightly different times, leading to a misalignment in fast-moving parts of the image. This can cause artifacts like "combing," where fast-moving objects appear to have a serrated edge. However, 1080i has been preferred in broadcast television due to its lower bandwidth requirements, making it more efficient for over-the-air or cable transmission. [2]
The origins of 1080i can be traced from Multiple sub-Nyquist sampling encoding, a Japanese analog high-definition television system. 1080i emerged as a leading standard for HDTV broadcasts. Many broadcasters worldwide adopted it. The ATSC (Advanced Television Systems Committee) standards and the DVB (Digital Video Broadcasting) standards allowed for the transmission of 1080i video signals. The adoption of 1080i was particularly significant in sports broadcasting. The higher resolution allowed for more detail and clarity, especially in large stadium shots and fast-paced action. The format's efficiency in utilizing available bandwidth made it a practical choice for broadcasters. However, it required more complex processing on the receiving end to deinterlace the image for display on progressive-scan screens. Overall, 1080i played a crucial role in the early days of HDTV. It bridged the gap between standard-definition broadcasts and the high-definition future that would soon become the norm. While its use has diminished with the rise of 1080p and 4K resolutions, 1080i remains an important milestone in the evolution of television technology. [3]
The core of 1080i is its resolution. The resolution is 1920x1080 pixels. This means that each video frame has 1,920 pixels horizontally and 1,080 pixels vertically. This results in over two million individual pixels per frame. This high resolution is why 1080i is called "high-definition". It offers a significant improvement over standard-definition formats, which typically have much lower pixel counts. The 1920x1080 resolution allows for greater detail and clarity in images. This makes it ideal for larger screens where higher pixel density is essential to maintain image quality. The increased resolution is particularly noticeable in fine details such as textures, text, and intricate patterns. These can be rendered with much greater accuracy than in lower-resolution formats. [4] [5]
The "i" in 1080i stands for interlaced. This refers to how each video frame is displayed. Instead of showing the entire frame at once, the interlacing technique divides each frame into two separate fields. The first field contains all the odd-numbered lines (1, 3, 5, etc.), and the second field contains all the even-numbered lines (2, 4, 6, etc.). These two fields are displayed one after the other. The odd lines are shown first, followed by the even lines. This happens very quickly, around 50 or 60 fields per second. The human eye sees these two fields as a single, continuous image. The main advantage of interlacing is that it allows for a higher frame rate without needing more bandwidth. This results in smoother motion, especially for content with moderate to fast movement, like sports broadcasts.
However, interlacing also has some drawbacks. Since the two fields are captured at slightly different times, fast-moving objects can appear misaligned between the two fields. This creates a visual artifact called "combing." This can reduce image quality, especially in scenes with a lot of motion. Modern display devices often use deinterlacing algorithms to combine the two fields into a single progressive image before displaying it. [5] [6] [7]
The frame rate of 1080i is usually 50 or 60 Hz. It depends on the region. In areas using the PAL or SECAM standards, like Europe and parts of Asia, the frame rate is 50 Hz. In regions using NTSC, like North America and Japan, the frame rate is 60 Hz. The frame rate refers to how often a new field is shown per second. At 50 Hz, 50 fields are shown each second. This results in 25 full frames per second when the odd and even fields are combined. At 60 Hz, 60 fields are shown per second. This results in 30 full frames per second. Interlacing affects how motion is perceived in 1080i. Since each field represents a slightly different moment in time, motion can appear smoother compared to lower frame rate progressive scans. However, this also means 1080i can struggle with fast-moving scenes. The interlaced fields might not perfectly align, leading to motion artifacts. [5] [8] 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. [9] Resolutions of 1080i60 or 1080i50 often refers to 1080i/30 or 1080i/25 in EBU notation.
The 1080i video signals can be carried by four main digital television broadcast systems: ATSC, DVB, ISDB and DTMB. In both ATSC and DVB systems, the 1080i signal is compressed using codecs like MPEG-2 or H.264 to reduce the bandwidth required for transmission.
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.
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 characteristics of the human visual system.
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 international set of standards for broadcast and 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 other 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, VHS, Laserdisc, 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.
D-5 is a professional digital video format introduced by Panasonic at 18th International Television Symposium in Montreux in 1993 and released a year later in 1994. Like Sony's D-1 (8-bit), it is an uncompressed digital component system (10-bit), but uses the same half-inch tapes as Panasonic's digital composite D-3 format. A 120 min. D-3 tape will record 60 min. in D-5/D-5 HD mode. D-5 standard definition (SD) decks can be retrofitted to record high definition with the use of an external HD input/output box/decoder. There were native D5 HD decks as well that didn't need an external processor and could record in both SD and HD. High definition conversion on D5 HD decks does not allow for any error correction that exists on standard definition recordings, as the full bandwidth of the tape is required for high definition recording.
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.
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, Myanmar, Western Sahara, and most of the Americas. The other common standard definition digital standard, used in the rest of the world, is 576i.
576i is a standard-definition digital video mode, originally used for digitizing 625 line analogue television in most countries of the world where the utility frequency for electric power distribution is 50 Hz. Because of its close association with the legacy colour encoding systems, it is often referred to as PAL, PAL/SECAM or SECAM when compared to its 60 Hz NTSC-colour-encoded counterpart, 480i.
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 referred to as 2K resolution, other sources differentiate between 1080p and (true) 2K resolution.
In video, a field is one of the many still images displayed sequentially to create the impression of motion on the screen. Normally, two fields comprise one video frame, in what is known as 2:1 interlacing. 3:1, 4:1 and 5:1 interlacing also exist. 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. Sometimes in interlaced video a field is called a frame which can lead to confusion.
HD Lite is the re-transmission of a particular HDTV channel at reduced picture quality compared to the original source stream.
MUSE, commercially known as Hi-Vision was a Japanese analog high-definition television system, with design efforts going back to 1979.
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 refers to the generation following standard-definition television (SDTV). It is the standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television.
DVB 3D-TV is a deprecated standard that partially came out at the end of 2010 which included techniques and procedures to send a three-dimensional video signal through actual DVB transmission standards. There was a commercial requirement text for 3D TV broadcasters and Set-top box manufacturers, but no technical information was in there.
