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71-410: The Colorplus has twice the memory of a standard CGA board (32k, compared to 16k). The additional memory can be used in graphics modes to double the color depth , giving two additional graphics modes—16 colors at 320 × 200 resolution, or 4 colors at 640 × 200 resolution. It uses the same Motorola MC6845 display controller as the previous MDA and CGA adapters. The original card also includes

142-536: A parallel printer port . CGA compatible modes: In addition to the CGA modes, it offers: The "new" font was actually the unused "thin" font already present in the IBM CGA ROMs , with 1-pixel wide vertical strokes. This offered greater clarity on RGB monitors, versus the default "thick" / 2-pixel font more suitable for output to composite monitors and over RF to televisions but, contrary to Plantronics' advertising claims,

213-451: A 4-level alpha channel ); the Cineon file format , for example, used this. Some SGI systems had 10- (or more) bit digital-to-analog converters for the video signal and could be set up to interpret data stored this way for display. BMP files define this as one of its formats, and it is called "HiColor" by Microsoft . Video cards with 10 bits per component started coming to market in

284-456: A bit depth of 8 bits to 16 bits per sample. As of 2020, some smartphones have started using 30-bit color depth, such as the OnePlus ;8 Pro , Oppo Find X2 & Find X2 Pro, Sony Xperia 1 II , Xiaomi Mi 10 Ultra , Motorola Edge+ , ROG Phone 3 and Sharp Aquos Zero 2. Using 12 bits per color channel produces 36 bits, 68,719,476,736 colors. If an alpha channel of

355-552: A color channel is also known as radiometric resolution , especially in the context of satellite images . With the relatively low color depth, the stored value is typically a number representing the index into a color map or palette (a form of vector quantization ). The colors available in the palette itself may be fixed by the hardware or modifiable by software. Modifiable palettes are sometimes referred to as pseudocolor palettes. Old graphics chips, particularly those used in home computers and video game consoles , often have

426-412: A color cube in the palette for a direct-color system (and so all programs would use the same palette). Usually fewer levels of blue were provided than others, since the normal human eye is less sensitive to the blue component than to either red or green (two thirds of the eye's receptors process the longer wavelengths ). Popular sizes were: 4,096 colors, usually from a fully-programmable palette (though it

497-499: A contemporary laser printer) but color proved more popular. 4 colors, usually from a selection of fixed palettes. Gray-scale early NeXTstation , color Macintoshes, Atari ST medium resolution. 8 colors, almost always all combinations of full-intensity red, green, and blue. Many early home computers with TV displays, including the ZX Spectrum and BBC Micro . 16 colors, usually from a selection of fixed palettes. Used by IBM CGA (at

568-406: A factor with low-quality or overly long cables. Solutions include shielded cables, cables that include a separate internal coaxial cable for each color signal, and "broken out" cables utilizing a separate coaxial cable with a BNC connector for each color signal. BNC breakout cables typically use five connectors, one each for Red, Green, Blue, Horizontal Sync, and Vertical Sync, and do not include

639-409: A fixed line scan (H-scan) rate – "multisync" monitors being, at the time, expensive rarities – and so the vertical/frame (V-scan) refresh rate had to be reduced in order to accommodate them, which increased visible flicker and thus eye strain . For example, the highest 800 × 600 mode, being otherwise based on the matching SVGA resolution (with 628 total lines), reduced

710-488: A graphical boot screen, while text-mode boot uses 720 × 400 @ 70 Hz. This convention has been eroded in recent years, however, with POST and BIOS screens moving to higher resolutions, taking advantage of EDID data to match the resolution to a connected monitor. 640 × 480 @ 60 Hz is the default Windows graphics mode (usually with 16 colors), up to Windows 2000. It remains an option in XP and later versions via

781-456: A low-resolution CGA display simultaneously. Many programmers also used such a setup with the monochrome card displaying debugging information while a program ran in graphics mode on the other card. Several debuggers, like Borland's Turbo Debugger , D86 and Microsoft's CodeView could work in a dual monitor setup. Either Turbo Debugger or CodeView could be used to debug Windows. There were also device drivers such as ox.sys , which implemented

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852-497: A much wider range of resolutions and refresh rates at arbitrary sync frequencies and pixel clock rates. For the most common VGA mode ( 640 × 480 , 60 Hz, non-interlaced ), the horizontal timings can be found in the HP Super VGA Display Installation Guide and in other places. 640 × 400 @ 70 Hz is traditionally the video mode used for booting VGA-compatible x86 personal computers that show

923-457: A separate display adapter installed in a slot in order to connect a monitor. The term "array" rather than "adapter" in the name denoted that it was not a complete independent expansion device, but a single component that could be integrated into a system. Unlike the graphics adapters that preceded it ( MDA , CGA , EGA and many third-party options) there was initially no discrete VGA card released by IBM. The first commercial implementation of VGA

994-639: A serial interface simulation on the monochrome display and, for example, allowed the user to receive crash messages from debugging versions of Windows without using an actual serial terminal. It is also possible to use the "MODE MONO" command at the command prompt to redirect the output to the monochrome display. When a monochrome adapter was not present, it was possible to use the 0xB000–0xB7FF address space as additional memory for other programs. A VGA-capable PCI / PCIe graphics card can provide legacy VGA registers in its PCI configuration space , which may be remapped by BIOS or operating system . "Unchaining"

1065-478: A single pixel. When referring to a pixel, the concept can be defined as bits per pixel (bpp). When referring to a color component, the concept can be defined as bits per component , bits per channel , bits per color (all three abbreviated bpc), and also bits per pixel component , bits per color channel or bits per sample (bps). Modern standards tend to use bits per component, but historical lower-depth systems used bits per pixel more often. Color depth

1136-450: A visually lossless low-latency algorithm based on predictive DPCM and YCoCg-R color space and allows increased resolutions and color depths and reduced power consumption." At WinHEC 2008, Microsoft announced that color depths of 30 bits and 48 bits would be supported in Windows 7 , along with the wide color gamut scRGB . High Efficiency Video Coding (HEVC or H.265) defines

1207-413: A yellow subpixel. However, formats and media that allow or make use of the extended color gamut are at present extremely rare. Because humans are overwhelmingly trichromats or dichromats one might suppose that adding a fourth "primary" color could provide no practical benefit. However humans can see a broader range of colors than a mixture of three colored lights can display. The deficit of colors

1278-599: Is backward compatible with the EGA and CGA adapters, but supports extra bit depth for the palette when in these modes. For instance, when in EGA 16-color modes, VGA offers 16 palette registers, and in 256-color modes, it offers 256 registers. Each palette register contain a 3×6 bit RGB value, selecting a color from the 18-bit gamut of the DAC . These color registers are initialized to default values IBM expected to be most useful for each mode. For instance, EGA 16-color modes initialize to

1349-414: Is also often used to refer to all color depths greater or equal to 24. Deep color consists of a billion or more colors. 2 is 1,073,741,824. Usually this is 10 bits each of red, green, and blue (10 bpc). If an alpha channel of the same size is added then each pixel takes 40 bits. Some earlier systems placed three 10-bit channels in a 32-bit word , with 2 bits unused (or used as

1420-482: Is also provide this port-mapped I/O segment: Due to the use of different address mappings for different modes, it is possible to have a monochrome adapter (i.e. MDA or Hercules ) and a color adapter such as the VGA, EGA , or CGA installed in the same machine. At the beginning of the 1980s, this was typically used to display Lotus 1-2-3 spreadsheets in high-resolution text on a monochrome display and associated graphics on

1491-554: Is assigned 5 bits, plus one unused bit (or used for a mask channel or to switch to indexed color); this allows 32,768 colors to be represented. However, an alternate assignment which reassigns the unused bit to the G channel allows 65,536 colors to be represented, but without transparency. These color depths are sometimes used in small devices with a color display, such as mobile phones, and are sometimes considered sufficient to display photographic images. Occasionally 4 bits per color are used plus 4 bits for alpha, giving 4,096 colors. Among

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1562-421: Is only one aspect of color representation, expressing the precision with which the amount of each primary can be expressed; the other aspect is how broad a range of colors can be expressed (the gamut ). The definition of both color precision and gamut is accomplished with a color encoding specification which assigns a digital code value to a location in a color space . The number of bits of resolved intensity in

1633-515: Is particularly noticeable in saturated shades of bluish green (shown as the left upper grey part of the horseshoe in the diagram) of RGB displays: Most humans can see more vivid blue-greens than any color video screen can display. Video Graphics Array Video Graphics Array ( VGA ) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in

1704-407: Is sometimes seen is 80 × 30 or 80 × 60 , using an 8 × 16 or 8 × 8 font and an effective 640 × 480 pixel display, which trades use of the more flickery 60 Hz mode for an additional 5 or 10 lines of text and square character blocks (or, at 80 × 30 , square half-blocks). Unlike the cards that preceded it, which used binary TTL signals to interface with a monitor (and also composite , in

1775-527: Is used by virtually every computer and phone display and the vast majority of image storage formats . Almost all cases of 32 bits per pixel assigns 24 bits to the color, and the remaining 8 are the alpha channel or unused. 2 gives 16,777,216 color variations. The human eye can discriminate up to ten million colors, and since the gamut of a display is smaller than the range of human vision, this means this should cover that range with more detail than can be perceived. However, displays do not evenly distribute

1846-581: The IBM PC compatible industry within three years. The term can now refer to the computer display standard , the 15-pin D-subminiature VGA connector , or the 640 × 480 resolution characteristic of the VGA hardware. VGA was the last IBM graphics standard to which the majority of IBM PC compatible computer manufacturers conformed, making it the lowest common denominator that virtually all post-1990 PC graphics hardware can be expected to implement. VGA

1917-504: The NTSC-M video system, as this made it much easier to offer optional TV-out solutions or external VGA-to-TV converter boxes at the time of VGA's development. It is also at least nominally twice that of CGA, which also supported composite monitors . All derived VGA timings (i.e. those which use the master 25.175 and 28.322 MHz crystals and, to a lesser extent, the nominal 31.469 kHz line rate) can be varied by software that bypasses

1988-747: The Nvidia Quadro graphics cards manufactured after 2006 support 30-bit deep color and Pascal or later GeForce and Titan cards when paired with the Studio Driver as do some models of the Radeon HD ;5900 series such as the HD ;5970. The ATI FireGL V7350 graphics card supports 40- and 64-bit pixels (30 and 48 bit color depth with an alpha channel). The DisplayPort specification also supports color depths greater than 24 bpp in version 1.3 through " VESA Display Stream Compression , which uses

2059-468: The cathode-ray tube controller ( CRTC ) was integrated into a main VGA chip, which eliminated several other chips in previous graphics adapters, so VGA only additionally required external video RAM and timing crystals . This small part count allowed IBM to include VGA directly on the PS/2 motherboard, in contrast to prior IBM PC models – PC , PC/XT , and PC AT  – which required

2130-485: The color gamut of a display, since it is no longer limited to the interior of a triangle formed by three primaries at its corners, e.g. the CIE 1931 color space . Recent technologies such as Texas Instruments 's BrilliantColor augment the typical red, green, and blue channels with up to three other primaries: cyan, magenta, and yellow. Cyan would be indicated by negative values in the red channel, magenta by negative values in

2201-436: The open standard image file format OpenEXR which supported 16-bit-per-channel half-precision floating-point numbers. At values near 1.0, half precision floating point values have only the precision of an 11-bit integer value, leading some graphics professionals to reject half-precision in situations where the extended dynamic range is not needed. Virtually all television displays and computer displays form images by varying

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2272-530: The "VGA" graphics mode remained a compatibility option for PC operating systems. Nonstandard display modes can be implemented, with horizontal resolutions of: And heights of: For example, high resolution modes with square pixels are available at 768 × 576 or 704 × 528 in 16 colors, or medium-low resolution at 320 × 240 with 256 colors. Alternatively, extended resolution is available with "fat" pixels and 256 colors using, e.g. 400 × 600 (50 Hz) or 360 × 480 (60 Hz), and "thin" pixels, 16 colors and

2343-639: The 256 KB VGA memory into four separate "planes" makes VGA's 256 KB of RAM available in 256-color modes. There is a trade-off for extra complexity and performance loss in some types of graphics operations, but this is mitigated by other operations becoming faster in certain situations: Software such as Fractint , Xlib and ColoRIX also supported tweaked 256-color modes on standard adaptors using freely-combinable widths of 256, 320, and 360 pixels and heights of 200, 240 and 256 (or 400, 480 and 512) lines, extending still further to 384 or 400 pixel columns and 576 or 600 (or 288, 300). However, 320 × 240

2414-570: The 256-color palette. The CPU interface combines the 4 planes in the same way, a feature called "chain-4", so that each pixel appears to the CPU as a packed 8-bit value representing the palette index. The video memory of the VGA is mapped to the PC's memory via a window in the range between segments 0xA0000 and 0xBFFFF in the PC's real mode address space (A000:0000 and B000:FFFF in segment:offset notation). Typically, these starting segments are: A typical VGA card

2485-514: The 70 Hz refresh rate with e.g. 736 × 410 mode. "Narrow" modes such as 256 × 224 tend to preserve the same pixel ratio as in e.g. 320 × 240 mode unless the monitor is adjusted to stretch the image out to fill the screen, as they are derived simply by masking down the wider mode instead of altering pixel or line timings, but can be useful for reducing memory requirements and pixel addressing calculations for arcade game conversions or console emulators. The PC version of Pinball Fantasies has

2556-650: The Main ;10 profile, which allows for 8 or 10 bits per sample with 4:2:0 chroma subsampling . The Main 10 profile was added at the October ;2012 HEVC meeting based on proposal JCTVC-K0109 which proposed that a 10-bit profile be added to HEVC for consumer applications. The proposal stated that this was to allow for improved video quality and to support the Rec. 2020 color space that will be used by UHDTV . The second version of HEVC has five profiles that allow for

2627-609: The VGA firmware interface and communicates directly with the VGA hardware, as many MS-DOS based games did. However, only the standard modes, or modes that at least use almost exactly the same H-sync and V-sync timings as one of the standard modes, can be expected to work with the original late-1980s and early-1990s VGA monitors. The use of other timings may in fact damage such monitors and thus was usually avoided by software publishers. Third-party "multisync" CRT monitors were more flexible, and in combination with "super EGA", VGA, and later SVGA graphics cards using extended modes, could display

2698-444: The ability to use a different palette per sprites and tiles in order to increase the maximum number of simultaneously displayed colors, while minimizing use of then-expensive memory (and bandwidth). For example, in the ZX Spectrum the picture is stored in a two-color format, but these two colors can be separately defined for each rectangular block of 8×8 pixels. The palette itself has a color depth (number of bits per entry). While

2769-443: The best VGA systems only offered an 18-bit (262,144 color) palette from which colors could be chosen, all color Macintosh video hardware offered a 24-bit (16 million color) palette. 24-bit palettes are nearly universal on any recent hardware or file format using them. If instead the color can be directly figured out from the pixel values, it is "direct color". Palettes were rarely used for depths greater than 12 bits per pixel, as

2840-423: The boot menu "low resolution video" option and per-application compatibility mode settings, despite newer versions of Windows now defaulting to 1024 × 768 and generally not allowing any resolution below 800 × 600 to be set. The need for such a low-quality, universally compatible fallback has diminished since the turn of the millennium, as VGA-signalling-standard screens or adaptors unable to show anything beyond

2911-413: The bottom 2 bits of 8-bit data, but if 16 bits were used it would lose none of the 8-bit data). In addition, digital cameras are able to produce 10 or 12 bits per channel in their raw data; as 16 bits is the smallest addressable unit larger than that, using it would make it easier to manipulate the raw data. Some systems started using those bits for numbers outside the 0–1 range rather than for increasing

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2982-460: The case of the CGA), the VGA introduced a video interface using pure analog RGB signals , with a range of 0.7 volts peak-to-peak max. In conjunction with a 18-bit RAMDAC (6-bit per RGB channel), this produced a color gamut of 262,144 colors. The original VGA specifications follow: The intended standard value for the horizontal frequency of VGA's 640 × 480 mode is exactly double the value used in

3053-400: The colors in human perception space, so humans can see the changes between some adjacent colors as color banding . Monochromatic images set all three channels to the same value, resulting in only 256 different colors; some software attempts to dither the gray level into the color channels to increase this, although in modern software this is more often used for subpixel rendering to increase

3124-509: The default CGA 16-color palette, and the 256-color mode initializes to a palette consisting of 16 CGA colors, 16 grey shades, and then 216 colors chosen by IBM to fit expected use cases. After initialization they can be redefined at any time without altering the contents of video RAM, permitting palette cycling . In the 256-color modes, the DAC is set to combine four 2-bit color values, one from each plane, into an 8-bit-value representing an index into

3195-491: The extra modes (usually describing them simply as 'Plantronics mode'). The Thomson TO16 (a PC-XT compatible) and the Olivetti M19 supported Plantronics modes, along with CGA. Color depth Color depth or colour depth (see spelling differences ), also known as bit depth , is either the number of bits used to indicate the color of a single pixel , or the number of bits used for each color component of

3266-763: The first hardware to use the standard were the Sharp X68000 and IBM's Extended Graphics Array (XGA). The term "high color" has recently been used to mean color depths greater than 24 bits. Almost all of the least expensive LCDs (such as typical twisted nematic types) provide 18-bit color (64×64×64 = 262,144 combinations) to achieve faster color transition times, and use either dithering or frame rate control to approximate 24-bit-per-pixel true color, or throw away 6 bits of color information entirely. More expensive LCDs (typically IPS ) can display 24-bit color depth or greater. 24 bits almost always use 8 bits each of R, G, and B (8 bpc). As of 2018, 24-bit color depth

3337-579: The fraction. The Cineon imaging system used 10-bit professional video displays with the video hardware adjusted so that a value of 95 was black and 685 was white. The amplified signal tended to reduce the lifetime of the CRT. More bits also encouraged the storage of light as linear values, where the number directly corresponds to the amount of light emitted. Linear levels makes calculation of computer graphics much easier. However, linear color results in disproportionately more samples near white and fewer near black, so

3408-414: The green channel, and yellow by negative values in the blue channel, validating the use of otherwise fictitious negative numbers in the color channels. Mitsubishi and Samsung (among others) use BrilliantColor in some of their TV sets to extend the range of displayable colors. The Sharp Aquos line of televisions has introduced Quattron technology, which augments the usual RGB pixel components with

3479-557: The horizontal dimension), vertical roll, poor horizontal sync or even a complete lack of picture depending on the exact mode attempted. Due to these potential issues, most VGA tweaks used in commercial products were limited to more standards-compliant, "monitor-safe" combinations, such as 320 × 240 (square pixels, three video pages, 60 Hz), 320 × 400 (double resolution, two video pages, 70 Hz), and 360 × 480 (highest resolution compatible with both standard VGA monitors and cards, one video page, 60 Hz) in 256 colors, or double

3550-590: The late 1990s. An early example was the Radius ThunderPower card for the Macintosh, which included extensions for QuickDraw and Adobe Photoshop plugins to support editing 30-bit images. Some vendors call their 24-bit color depth with FRC panels 30-bit panels; however, true deep color displays have 10-bit or more color depth without FRC. The HDMI  1.3 specification defines a bit depth of 30 bits (as well as 36 and 48 bit depths). In that regard,

3621-586: The lowest resolution), EGA , and by the least common denominator VGA standard at higher resolution. Color Macintoshes, Atari ST low resolution, Commodore 64 , and Amstrad CPCs also supported 4-bit color. 32 colors from a programmable palette, used by the Original Amiga chipset . 64 colors. Used by the Master System , Enhanced Graphics Adapter, GIME for TRS-80 Color Computer 3, Pebble Time smartwatch (64 color e-paper display), and Parallax Propeller using

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3692-472: The memory consumed by the palette would exceed the necessary memory for direct color on every pixel. 2 colors, often black and white direct color. Sometimes 1 meant black and 0 meant white, the inverse of modern standards. Most of the first graphics displays were of this type, the X Window System was developed for such displays, and this was assumed for a 3M computer . In the late 1980s there were professional displays with resolutions up to 300 dpi (the same as

3763-446: The mid 1990s, a 640 × 480 ×16 graphics mode using the VGA memory and register specifications was expected by operating systems such as Windows 95 and OS/2 Warp 3.0 , which provided no support for lower resolutions or bit depths, or support for other memory or register layouts without additional drivers. Well into the 2000s, even after the VESA standard for graphics cards became commonplace,

3834-796: The monitor. The 400-line signal was the same as the standard 80 × 25 text mode, which meant that pressing Esc to return to text mode didn't change the frequency of the video signal, and thus the monitor did not have to resynchronize (which could otherwise have taken several seconds). The standard VGA monitor interface is a 15-pin D-subminiature connector in the "E" shell, variously referred to as "DE-15", "HD-15" and erroneously "DB-15(HD)". All VGA connectors carry analog RGBHV (red, green, blue, horizontal sync , vertical sync ) video signals. Modern connectors also include VESA DDC pins, for identifying attached display devices. Because VGA uses low-voltage analog signals, signal degradation becomes

3905-421: The option to use non-standard modes "high res" modes, such as 640 × 350 , allowing it to display a larger portion of the pinball table on screen. VGA also implements several text modes: As with the pixel-based graphics modes, additional text modes are possible by programming the VGA correctly, with an overall maximum of about 100 × 80 cells and an active area spanning about 88 × 64 cells. One variant that

3976-423: The original resolutions have become increasingly rare. 320 × 200 at 70 Hz was the most common mode for early 1990s PC games, with pixel-doubling and line-doubling performed in hardware to present a 640 × 400 at 70 Hz signal to the monitor. The Windows 95/98/Me LOGO.SYS boot-up image was 320 × 400 resolution, displayed with pixel-doubling to present a 640 × 400 at 70 Hz signal to

4047-408: The other signal lines of the VGA interface. With BNC, the coaxial wires are fully shielded end-to-end and through the interconnect so that virtually no crosstalk and very little external interference can occur. The use of BNC RGB video cables predates VGA in other markets and industries. The VGA color system uses register-based palettes to map colors in various bit depths to its 18-bit output gamut. It

4118-500: The palette with VGA-specific commands. The 640 × 480 resolution (at 256 colors rather than 16) was originally used by IBM in PGC graphics (which VGA offers no backward compatibility for) but did not see wide adoption until VGA was introduced. As the VGA began to be cloned in great quantities by manufacturers who added ever-increasing capabilities, its 640 × 480 , 16-color mode became the de facto lowest common denominator of graphics cards. By

4189-453: The quality of 16-bit linear is about equal to 12-bit sRGB . Floating point numbers can represent linear light levels spacing the samples semi-logarithmically. Floating point representations also allow for drastically larger dynamic ranges as well as negative values. Most systems first supported 32-bit per channel single-precision , which far exceeded the accuracy required for most applications. In 1999, Industrial Light & Magic released

4260-422: The reference VGA circuit. 256 colors, usually from a fully-programmable palette: Most early color Unix workstations, Super VGA , color Macintosh , Atari TT , Amiga AGA chipset , Falcon030 , Acorn Archimedes . Both X and Windows provided elaborate systems to try to allow each program to select its own palette, often resulting in incorrect colors in any window other than the one with focus. Some systems placed

4331-483: The refresh rate from 60 Hz to about 50 Hz (and 832 × 624 , the theoretical maximum resolution achievable with 256 KB at 16 colors, would have reduced it to about 48 Hz, barely higher than the rate at which XGA monitors employed a double-frequency interlacing technique to mitigate full-frame flicker). These modes were also outright incompatible with some monitors, producing display problems such as picture detail disappearing into overscan (especially in

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4402-422: The resolution. Numbers greater than 1 were for colors brighter than the display could show, as in high-dynamic-range imaging (HDRI). Negative numbers can increase the gamut to cover all possible colors, and for storing the results of filtering operations with negative filter coefficients. The Pixar Image Computer used 12 bits to store numbers in the range [-1.5, 2.5), with 2 bits for the integer portion and 10 for

4473-454: The same size is added then there are 48 bits per pixel. Using 16 bits per color channel produces 48 bits, 281,474,976,710,656 colors. If an alpha channel of the same size is added then there are 64 bits per pixel. Image editing software such as Adobe Photoshop started using 16 bits per channel fairly early in order to reduce the quantization on intermediate results (i.e. if an operation is divided by 4 and then multiplied by 4, it would lose

4544-466: The space resolution on LCD screens where the colors have slightly different positions. The DVD-Video and Blu-ray Disc standards support a bit depth of 8 bits per color in YCbCr with 4:2:0 chroma subsampling . YCbCr can be losslessly converted to RGB. MacOS refers to 24-bit colour as "millions of colours". The term true colour is sometimes used to mean what this article is calling direct colour . It

4615-406: The strength of just three primary colors : red, green, and blue. For example, bright yellow is formed by roughly equal red and green contributions, with no blue contribution. For storing and manipulating images, alternative ways of expanding the traditional triangle exist: One can convert image coding to use fictitious primaries, that are not physically possible but that have the effect of extending

4686-433: The triangle to enclose a much larger color gamut. An equivalent, simpler change is to allow negative numbers in color channels, so that the represented colors can extend out of the color triangle formed by the primaries. However these only extend the colors that can be represented in the image encoding; neither trick extends the gamut of colors that can actually be rendered on a display device. Supplementary colors can widen

4757-864: Was a built-in component of the IBM PS/2, in which it was accompanied by 256 KB of video RAM, and a new DE-15 connector replacing the DE-9 used by previous graphics adapters. IBM later released the standalone IBM PS/2 Display Adapter , which utilized the VGA but could be added to machines that did not have it built in. The VGA supports all graphics modes supported by the MDA, CGA and EGA cards, as well as multiple new modes. The 640 × 480 16-color and 320 × 200 256-color modes had fully redefinable palettes, with each entry selected from an 18-bit (262,144-color) gamut. The other modes defaulted to standard EGA or CGA compatible palettes and instructions, but still permitted remapping of

4828-679: Was adapted into many extended forms by third parties, collectively known as Super VGA , then gave way to custom graphics processing units which, in addition to their proprietary interfaces and capabilities, continue to implement common VGA graphics modes and interfaces to the present day. The VGA analog interface standard has been extended to support resolutions of up to 2048 × 1536 for general usage, with specialized applications improving it further still. The color palette random access memory (RAM) and its corresponding digital-to-analog converter (DAC) were integrated into one chip (the RAMDAC ) and

4899-551: Was drawn at the same 8 × 8 pixel resolution. Few software made use of the enhanced Plantronics modes, for which there was no BIOS support. A 1984 advertisement listed the following software as compatible: Some contemporary software has added support for Plantronics modes: Some third-party CGA and EGA clones, such as the ATI Graphics Solution and the Paradise AutoSwitch EGA 480 , could emulate

4970-466: Was often set to a 16×16×16 color cube). Some Silicon Graphics systems, Color NeXTstation systems, and Amiga systems in HAM mode have this color depth. RGBA4444, a related 16 bpp representation providing the color cube and 16 levels of transparency, is a common texture format in mobile graphics. In high-color systems, two bytes (16 bits) are stored for each pixel. Most often, each component (R, G, and B)

5041-507: Was the best known and most frequently used, as it offered a standard 40-column resolution and 4:3 aspect ratio with square pixels. " 320 × 240  × 8" resolution was commonly called Mode X , the name used by Michael Abrash when he presented the resolution in Dr. Dobb's Journal . The highest resolution modes were only used in special, opt-in cases rather than as standard, especially where high line counts were involved. Standard VGA monitors had

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