JPEG image [de]compression software
JPEG image [de]compression software
This is the jpeg + cjpeg + libjpeg source directory.
This directory contains the fourth public release of the Independent JPEG Group's free JPEG file format image compression/decompression software including images of libjpeg.a, cjpeg, and djpeg.
JPEG is a standardized compression method for fullcolor and gray-scale images. JPEG is intended for compressing "real-world" scenes; cartoons and other non-realistic images are not its strong suit. JPEG is lossy, meaning that the output image is not necessarily identical to the input image. Hence you must not use JPEG if you have to have identical output bits. However, on typical images of real-world scenes, very good compression levels can be obtained with no visible change, and amazingly high compression levels are possible if you can tolerate a low-quality image.
Support has been added to manipulate SGI image files to/from jpeg format. To compress an SGI image file, simply name the SGI image file on the cjpeg command line:
cjpeg in.rgb > in.jpg
To decompress a .jpg image into an SGI image file specify -sgi on the djpeg command line:
djpeg -sgi < in.jpg > out.rgb
movie in.rgb out.rgb -z 2
This directory contains MANY files, most of which are the actual source code and headers employed to build the cjpeg and djpeg compression and decompress binaries, as well as the libjpeg.a library. Rather than include links to each and every one, the following "documentation" sublist, plus the Makefile itself, are browsable thru this interface,
The output of the compile looks like this:
--- cjpeg ---
//usr/bin/cc -xansi -O -D__STDC__ -nostdinc
-I//usr/include -O -MDupdate Makedepend -woff 515,608,658,799
-o cjpeg jcmain.o jcmaster.o jcdeflts.o jcarith.o jccolor.o
jcexpand.o jchuff.o jcmcu.o jcpipe.o jcsample.o jfwddct.o
jwrjfif.o jrdgif.o jrdppm.o jrdrle.o jrdtarga.o jrdsgi.o
jutils.o jerror.o jmemmgr.o jmemsys.o -nostdlib
-L//lib -L//usr/lib -limage
--- djpeg ---
//usr/bin/cc -xansi -O -D__STDC__ -nostdinc
-I//usr/include -O -MDupdate Makedepend -woff 515,608,658,799
-o djpeg jdmain.o jdmaster.o jddeflts.o jbsmooth.o jdarith.o
jdcolor.o jdhuff.o jdmcu.o jdpipe.o jdsample.o jquant1.o
jquant2.o jrevdct.o jrdjfif.o jwrgif.o jwrppm.o jwrrle.o
jwrtarga.o jwrsgi.o jutils.o jerror.o jmemmgr.o jmemsys.o
-nostdlib -L//lib -L//usr/lib -limage
--- libjpeg.a ---
rm -f libjpeg.a
ar rc libjpeg.a jcmaster.o jcdeflts.o jcarith.o
jccolor.o jcexpand.o jchuff.o jcmcu.o jcpipe.o jcsample.o
jfwddct.o jwrjfif.o jrdgif.o jrdppm.o jrdrle.o jrdtarga.o
jrdsgi.o jdmaster.o jddeflts.o jbsmooth.o jdarith.o
jdcolor.o jdhuff.o jdmcu.o jdpipe.o jdsample.o jquant1.o
jquant2.o jrevdct.o jrdjfif.o jwrgif.o jwrppm.o jwrrle.o
jwrtarga.o jwrsgi.o jutils.o jerror.o jmemmgr.o jmemsys.o
ar -ts libjpeg.a
[same as the list of .o files above]
OR, ...