bits per pixel
<hardware, graphics> (bpp) The number of bits of information stored per
pixel of an image or displayed by a graphics adapter. The more bits there are,
the more colours can be represented, but the more memory is required to store or
display the image.
A colour can be described by the intensities of red, green and blue (RGB)
components. Allowing 8 bits (1 byte) per component (24 bits per pixel) gives 256
levels for each component and over 16 million different colours - more than the
human eye can distinguish. Microsoft Windows [and others?] calls this
truecolour. An image of 1024x768 with 24 bpp requires over 2 MB of memory.
"High colour" uses 16 bpp (or 15 bpp), 5 bits for blue, 5 bits for red and 6
bits for green. This reduced colour precision gives a slight loss of image
quality at a 1/3 saving on memory.
Standard VGA uses a palette of 16 colours (4 bpp), each colour in the palette is
24 bit. Standard SVGA uses a palette of 256 colours (8 bpp).
Some graphics hardware and software support 32-bit colour depths, including an
8-bit "alpha channel" for transparency effects.
(1999-08-01)
Nearby terms:
bit rot « bit slice « bits per inch « bits per pixel
» bits per second » bit string » bit stuffing
