The display resolution or display modes of a digital television, computer monitor, or other display device is the number of distinct 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 (including liquid-crystal displays) and projection displays using fixed picture-element (pixel) arrays.
It is usually quoted as , with the units in pixels: for example, means the width is 1024 pixels and the height is 768 pixels. This example would normally be spoken as "ten twenty-four by seven sixty-eight" or "ten twenty-four by seven six eight".
One use of the term display resolution applies to fixed-pixel-array displays such as plasma display panels (PDP), liquid-crystal displays (LCD), Digital Light Processing (DLP) projectors, AMOLED displays, and similar technologies, and is simply the physical number of columns and rows of pixels creating the display (e.g. ). A consequence of having a fixed-grid display is that, for multi-format video inputs, all displays need a "scaling engine" (a digital video processor that includes a memory array) to match the incoming picture format to the display.
For device displays such as phones, tablets, monitors and televisions, the use of the term display resolution as defined above is a misnomer, though common. The term display resolution is usually used to mean pixel dimensions, the maximum number of pixels in each dimension (e.g. ), which does not tell anything about the pixel density of the display on which the image is actually formed: resolution properly refers to the pixel density, the number of pixels per unit distance or area, not the total number of pixels. In digital measurement, the display resolution would be given in pixels per inch (PPI). In analog measurement, if the screen is 10 inches high, then the horizontal resolution is measured across a square 10 inches wide. For television standards, this is typically stated as "lines horizontal resolution, per picture height"; for example, analog NTSC TVs can typically display about 340 lines of "per picture height" horizontal resolution from over-the-air sources, which is equivalent to about 440 total lines of actual picture information from left edge to right edge.
The eye's perception of display resolution can be affected by a number of factors see image resolution and optical resolution. One factor is the display screen's rectangular shape, which is expressed as the ratio of the physical picture width to the physical picture height. This is known as the aspect ratio. A screen's physical aspect ratio and the individual pixels' aspect ratio may not necessarily be the same. An array of on a display has square pixels, but an array of on a 16:9 display has oblong pixels.
An example of pixel shape affecting "resolution" or perceived sharpness: displaying more information in a smaller area using a higher resolution makes the image much clearer or "sharper". However, most recent screen technologies are fixed at a certain resolution; making the resolution lower on these kinds of screens will greatly decrease sharpness, as an interpolation process is used to "fix" the non-native resolution input into the display's native resolution output.
While some CRT-based displays may use digital video processing that involves image scaling using memory arrays, ultimately "display resolution" in CRT-type displays is affected by different parameters such as spot size and focus, astigmatic effects in the display corners, the color phosphor pitch shadow mask (such as Trinitron) in color displays, and the video bandwidth.
Computer displays including projectors generally do not overscan although many models (particularly CRT displays) allow it. CRT displays tend to be underscanned in stock configurations, to compensate for the increasing distortions at the corners.
The European Broadcasting Union has argued against interlaced video in production and broadcasting. The main argument is that no matter how complex the deinterlacing algorithm may be, the artifacts in the interlaced signal cannot be completely eliminated because some information is lost between frames. Despite arguments against it, television standards organizations continue to support interlacing. It is still included in digital video transmission formats such as DV, DVB, and ATSC. New video compression standards like High Efficiency Video Coding are optimized for progressive scan video, but sometimes do support interlaced video.
Progressive scanning (alternatively referred to as noninterlaced scanning) is a format of displaying, storing, or transmitting in which all the lines of each Film 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 (each image called a video field) are drawn alternately, so that only half the number of actual image frames are used to produce video.
One of the drawbacks of using a classic television is that the computer display resolution is higher than the television could decode. Chroma resolution for NTSC/PAL televisions are bandwidth-limited to a maximum 1.5MHz, or approximately 160 pixels wide, which led to blurring of the color for 320- or 640-wide signals, and made text difficult to read (see example image below). Many users upgraded to higher-quality televisions with S-Video or RGBI inputs that helped eliminate chroma blur and produce more legible displays. The earliest, lowest cost solution to the chroma problem was offered in the Atari 2600 Video Computer System and the Apple II+, both of which offered the option to disable the color and view a legacy black-and-white signal. On the Commodore 64, the GEOS mirrored the Mac OS method of using black-and-white to improve readability.
The resolution ( with borders disabled) was first introduced by home computers such as the Amiga and, later, Atari Falcon. These computers used interlace to boost the maximum vertical resolution. These modes were only suited to graphics or gaming, as the flickering interlace made reading text in word processor, database, or spreadsheet software difficult. (Modern game consoles solve this problem by pre-filtering the 480i video to a lower resolution. For example, Final Fantasy XII suffers from flicker when the filter is turned off, but stabilizes once filtering is restored. The computers of the 1980s lacked sufficient power to run similar filtering software.)
The advantage of a overscanned computer was an easy interface with interlaced TV production, leading to the development of Newtek's Video Toaster. This device allowed Amigas to be used for CGI creation in various news departments (example: weather overlays), drama programs such as NBC's seaQuest and The WB's Babylon 5.
In the PC world, the IBM PS/2 VGA (multi-color) on-board graphics chips used a non-interlaced (progressive) 640 × 480 × 16 color resolution that was easier to read and thus more useful for office work. It was the standard resolution from 1990 to around 1996. The standard resolution was until around 2000. Microsoft Windows XP, released in 2001, was designed to run at minimum, although it is possible to select the original in the Advanced Settings window.
Programs designed to mimic older hardware such as Atari, Sega, or Nintendo game consoles (emulators) when attached to multiscan CRTs, routinely use much lower resolutions, such as or for greater authenticity, though other emulators have taken advantage of pixelation recognition on circle, square, triangle and other geometric features on a lesser resolution for a more scaled vector rendering. Some emulators, at higher resolutions, can even mimic the aperture grille and shadow masks of CRT monitors.
In 2002, XGA was the most common display resolution. Many web sites and multimedia products were re-designed from the previous format to the layouts optimized for .
The availability of inexpensive LCD monitors made the aspect ratio resolution of more popular for desktop usage during the first decade of the 21st century. Many computer users including CAD users, graphic artists and video game players ran their computers at resolution (UXGA) or higher such as QXGA if they had the necessary equipment. Other available resolutions included oversize aspects like SXGA+ and wide aspects like Wide XGA, WXGA+, WSXGA+, and WUXGA; monitors built to the 720p and 1080p standard were also not unusual among home media and video game players, due to the perfect screen compatibility with movie and video game releases. A new more-than-HD resolution of WQXGA was released in 30-inch LCD monitors in 2007.
In 2010, 27-inch LCD monitors with the resolution were released by multiple manufacturers, and in 2012, Apple introduced a display on the MacBook Pro. Panels for professional environments, such as medical use and air traffic control, support resolutions up to (or, more relevant for control rooms, pixels).
+ Common display resolutions (N/A = not applicable) |
0.47 |
N/A |
0.76 |
2.78 |
4.82 |
3.08 |
2.47 |
1.38 |
23.26 |
6.98 |
8.53 |
4.14 |
N/A |
2.23 |
20.41 |
0.93 |
0.51 |
N/A |
2.15 |
<2.4 |
N/A |
N/A |
N/A |
N/A |
N/A |
15.09 |
In recent years the 16:9 aspect ratio has become more common in notebook displays, and (HD) has become popular for most low-cost notebooks, while (FHD) and higher resolutions are available for more premium notebooks.
When a computer display resolution is set higher than the physical screen resolution ( native resolution), some video drivers make the virtual screen scrollable over the physical screen thus realizing a two dimensional virtual desktop with its viewport. Most LCD manufacturers do make note of the panel's native resolution as working in a non-native resolution on LCDs will result in a poorer image, due to dropping of pixels to make the image fit (when using DVI) or insufficient sampling of the analog signal (when using VGA connector). Few CRT manufacturers will quote the true native resolution, because CRTs are analog in nature and can vary their display from as low as 320 × 200 (emulation of older computers or game consoles) to as high as the internal board will allow, or the image becomes too detailed for the vacuum tube to recreate (i.e., analog blur). Thus, CRTs provide a variability in resolution that fixed resolution LCDs cannot provide.
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