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Almathera Ten Pack 3: CDPD 3
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amigajpeg-2
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1995-03-17
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Here are the Independent JPEG Group jpeg compress and decompressor (version 2),
compiled for the Amiga with with SAS/C 5.10a.
files:
AMIGA-NOTE - this file
README - original JPEG source package readme file
cjpeg - jpeg compressor executable
djpeg - jpeg decompressor executable
cjpeg020 - jpeg compressor optimized for 68020 and higher processors.
djpeg020 - jpeg decompressor optimized for 68020 and higher proc.
extensions to the original:
cjpeg can read IFF ILBM files, including HAM and 24-bit ILBM.
djpeg can directly produce IFF ILBM output, including 24-bit,
4-bit grayscale and HAM.
Quantized ILBM pictures (-q option) don't look good because of the single
pass color quantization algorithm used (same problem with GIF files).
Also, HAM conversion uses a really simple algorithm, and may not look
very good (of course depending on the picture).
If you want high quality output, use either PPM (default) or 24-bit ILBM
output and then convert with for example ADPRO (commercial) or wasp.
(note: wasp reads both PPM and 24-bit ILBM format, but djpeg (this version)
writes PPM files faster than ILBM files)
You can also use 24-bit ILBM output with cards/devices such as HAM-E,
DCTV, Video Toaster, GVP Impact Vision etc.
usage:
compressor:
cjpeg [-Q quality] [-o] [-T] [-d] source-file destination-file
the optional quality parameter affects compressed file size and picture
quality (the amount 'loss' of information in the compression)
range is 0 to 100, default is 75.
source file can be GIF, PPM, Targa or ILBM format (including HAM
and 24-bit ILBM). destination will be, of course, in JPEG JFIF format.
other options:
-T Targa input file mode.
-o optimize entropy encoding parameters.
-d debug mode.
decompressor:
djpeg [-b] [-q colors] [-D] [-g] [-G] [-T] [-I] [-H] [-d] source-file dest-file
options:
-b - cross-block smoothing. may increase image quality with pictures
compressed with high -Q values.
-q colors quantize the colors and generate a file with the given amount
of colors. note that a single pass quantization algorithm is used,
resulting in non-optimal image quality.
-D do not use dithering in quantization (changed from previous version).
-g generate grayscale image.
-G select GIF output file format.
-T select Targa output file format
-I select IFF ILBM output file format. if this is selected with -q,
a normal ILBM file will be created; with -g, a grayscale 4-bitplane
ILBM image will be created; otherwise, a 24-bit ILBM file format
will be used.
-H select IFF ILBM HAM output file format. this uses a simple
algorithm resulting in non-optimal image quality.
-d debug mode.
output file will be in raw PPM format if no other options are given.
source file must be in JPEG JFIF format (naturally...)
authors:
Original JPEG compressor/decompressor software is the work of Tom Lane,
Philip Gladstone, Luis Ortiz, and other members of the independent JPEG
group.
This port was done by Timo Rossi (email: trossi@jyu.fi)
(original v2 SAS/C makefile by Ed Hanway (sisd!jeh@uunet.uu.net))