Video Graphics Array
lastmod 2018-08-17created 2016-04-122 edits
Video Graphics Array, or VGA, is an analog computer display standard first released by IBM in 1987. Except in the Pocket PC market, where VGA is establishing itself as a new standard, VGA is not used for general purposes today. However, as the last standard that most computer manufacturers support by default, the VGA method is used on many PC display devices to show the screen before device drivers are loaded. For example, Microsoft Windows runs in VGA mode up to its loading screen.
The term VGA refers to a 640 x 480 image resolution regardless of hardware. The 15-pin D-sub VGA connector, still widely used to transmit analog video signals at all resolutions, is also sometimes called VGA.
VGA was officially superseded by IBM's XGA standard, but in practice it was superseded by SVGA, an improvement on VGA made by various compatible hardware manufacturers.
Vector video standards2
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VGA, CIF
If you work with PCs, you have probably heard a lot about VGA. In Korea, VGA is used as a general term for graphics cards, but it is also a unit of screen specification. VGA as a screen specification is short for Video Graphic Array and was created by IBM in 1987. It is not an internationally agreed standard but a unit advocated by a company, IBM, that defined the specification for the minimum unit of graphics displayed on a PC, and it became established as the graphics specification of the IBM-compatible PCs we know. (When Adapter is used instead of Array, it is also called a graphics adapter, that is, a graphics card.)
Generally, VGA is taken to mean a resolution of 640480. What this means is a way of expressing the picture elements (single dots, pixels) displayed on the screen as numbers in widthheight form, i.e., a resolution that can display 640 pixels horizontally and 480 pixels vertically. Monitors are wider than they are tall. Mobile phones, on the other hand, are taller than they are wide.
Hardly any PCs today would use a resolution of 640480. Today, PC monitor specifications support basic VGA and go beyond Super VGA, called 800600, to provide 1024*768 XGA (eXtended Graphic Array) by default. These days the trend is for XGA to become nearly the default.
There is a specification called QVGA. Here Q stands for Quarter, meaning 1/4. That is, 320240, which is 1/4 of 640480, is called QVGA. QVGA is a display specification used in mobile devices. For mobile phones, widthheight is sometimes given as 240320, but it is still QVGA.
Besides the VGA specification, there is a standard display specification called CIF (Common Intermediate Format). CIF resolutions differ slightly between NTSC-based and PAL-based systems. Generally, CIF refers to the PAL-based specification. CIF is 352288, a size similar to the 320240 of QVGA. CIF and QGVA are often adopted as mobile phone specifications, and the 176*144 screen size of QCIF is also widely used. However, displays are currently converging toward QVGA.
CIF is the standard in places doing video-related development. Many have rules requiring that the CIF size be met. CIF and QVGA are important specifications for businesses that manufacture mobile devices.
In particular, the QCIF and SQCIF (Sub Quarter CIF, 12896) specifications are commonly used as video encoding specifications. You can assume mobile movies and videos are produced in these specifications. These days, content producers are excited about VGA (640480) support in mobile devices. Displays moving into VGA territory means that PC specifications become possible.
As PCs and mobile devices increasingly converge, VGA support in mobile devices leads to the assumption that PC content can move to mobile without conversion. Conversely, the position of companies that provided content for the mobile field becomes disadvantageous, because advances in resolution mean that their own content competes with ordinary PC content. Higher resolution does not mean the screen becomes as large as a PC's. However, if pixels become finer and smaller, the display size can be smaller than existing PC specifications.