access 8x8 blocks in JPG

Giganews Newsgroups
Subject: access 8x8 blocks in JPG
Posted by:  Francesco Gallarotti (gallarot…@hotmail.com)
Date: Mon, 24 Nov 2003

Hi all,
is anybody aware of a library (in C/C++) or a method that allows to extract
color information for a block of pixels (say 8x8) inside a JPG file WITHOUT
having to spend time decompressing the entire image? Is it possible to do
that?
My program is interested in querying single pixels (or 8x8 blocks of pixels
if single is not possible) inside a JPG file but I really need speed and
also to save space in memory, therefore I am looking for a method that
doesn't require blowing up the entire image in memory to get a single pixel
out of it...
Any help and sugestion is really appreciated,

Francesco Gallarotti

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