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TheWriter
12-13-2003, 01:47 AM
I am curious, why is it there are so many 32 bit BMP files? They dont support alpha, so what is with the extra 8 bits?

EricChadwick
12-15-2003, 03:33 PM
They load faster.

"24 and 32 bpp bitmaps are TrueColor images - each color channel (except alpha channel - neither 24 nor 32 bpp bitmap stores it) uses one byte. The difference between these two formats is that 24 bpp bitmap stores each pixel as 3 bytes and 32 bpp bitmap - as 4 bytes (or double word), one byte of each pixel does not in use, in other words each pixel of 32 bpp bitmap is aligned on the CPU register (the overwhelming majority of modern computers works with 32 bit registers). It means such a files are loaded or saved quicker than 24 bpp ones, but takes more room (on one quarter). "

http://www.aurigma.com/support/default.aspx?section=onlinehelp&mainsrc=Help/GraphicsProcessor/BMPEncoderInfo.htm

gandalf_the_red
12-15-2003, 10:46 PM
That sounds a bit off. The slowest mechanism on a computer is the HD. By increasing the file size, you have more to read. I would imagine the extra lag in that cancels out any other speed you have with memory/ cpu cycles.

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