BPP
       Bridge Port Pair

	

	BPP
       Bits Per Pixel (BIT)

	

	bits per pixel
bpp
colour depth

    (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)