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Color depth, also known as bit depth, is either the number of bits used to indicate the color of a single pixel, in a bitmapped image or video frame buffer, or the number of bits used for each color component of a single pixel. For consumer video standards, such as High Efficiency Video Coding (H.265), the bit depth specifies the number of bits used for each color component.〔〔〔〔 When referring to a pixel the concept can be defined as bits per pixel (bpp), which specifies the number of bits used. When referring to a color component the concept can be defined as bits per channel (bpc), bits per color (bpc), or bits per sample (bps).〔〔 Color depth is only one aspect of color representation, expressing how finely ''levels'' of color can be expressed (a.k.a. color precision); 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. == Indexed color == (詳細はpalette. The colors available in the palette itself may be fixed by the hardware or modifiable within the limits of the hardware (for instance, both color Macintosh systems and VGA-equipped IBM-PCs typically ran at 8-bit due to limited VRAM, but while 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). Modifiable palettes are sometimes referred to as pseudocolor palettes. * 1-bit color (21 = 2 colors): monochrome, often black and white, compact Macintoshes, Atari ST. * 2-bit color (22 = 4 colors): CGA, gray-scale early NeXTstation, color Macintoshes, Atari ST. * 3-bit color (23 = 8 colors): many early home computers with TV displays, including the ZX Spectrum and BBC Micro * 4-bit color (24 = 16 colors): as used by EGA and by the least common denominator VGA standard at higher resolution, color Macintoshes, Atari ST, Commodore 64, Amstrad CPC. * 5-bit color (25 = 32 colors): Original Amiga chipset * 6-bit color (26 = 64 colors): Original Amiga chipset * 8-bit color (28 = 256 colors): most early color Unix workstations, VGA at low resolution, Super VGA, color Macintoshes, Atari TT, Amiga AGA chipset, Falcon030. * 12-bit color (212 = 4096 colors): some Silicon Graphics systems, Color NeXTstation systems, and Amiga systems in HAM mode. Old graphics chips, particularly those used in home computers and video game consoles, often feature an additional level of palette mapping in order to increase the maximum number of simultaneously displayed colors. 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 8x8 pixels. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「color depth」の詳細全文を読む スポンサード リンク
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