JPEGv42

Short:        V4.2 JPEG (en/de)coder for Retina owners
Type:         gfx/show
Architecture: m68k-amigaos

Version 4.2 of

JPEG - coder/decoder/viewer adapted for the Retina Gfx-Board
------------------------------------------------------------

(changes at the end of this file)

If you don't own a Retina graphics board, this
may just be a jpeg encoder/decoder for you.

Though RetinaDisplay is already able to display
JPEG pictures, here's a better alternative.

Included are two executables:

cjpeg  does JPEG-compression, just type
       cjpeg -h  for a short syntax summary.
       This program has just been adapted by
       me to use the multipic.library
       to read various picture formats

djpeg  does JPEG-decompression, and to this
       one I added the watch-directly-on-Retina
       feature, it's enabled by default.
       You may also try djpeg -h here.

Both programs are compiled from the official
"fourth public release of the Independent JPEG
Group's free JPEG software". Only djpeg has been
modified by me.

Why use djpeg instead of RetinaDisplay?

- djpeg is faster, it's even faster than most commercial
        jpeg-loaders available.
- djpeg lets you watch the picture while it's decoded
- djpeg supports more jpeg-derivatives
- djpeg supports 8-bit as well as 24-bit display on
        the retina board. Watching JPEGs with the
        -greyscale switch given is even faster.
- djpeg is able to do "color-quantization", that is,
        if you enable that feature by "-color 256",
        an 8-bit screen will be opened on the
        Retina, giving you the ability to watch even
        larger pictures than it may be possible
        in 24-bits.

REQUIREMENTS:

 You NEED to have IXEmul.library available, this library
 is part of Markus Wild's GNU C (2.3.3) port for the
 amiga. It's available from several ftp-servers.

NOTES:

 djpeg spits its output to standard I/O, unless
 you specify anything else with a redirection
 ("djpeg -targa bla.jpg >bla.targa")
 
 press CTRL-C when djpeg is finished to close the screen.

 I compiled a >=68020 and 68881 version, too, but there were
 no measurable speed-difference.


If anyone wants the source-code, he'd contact me via email,
my adress is lkv@mania.robin.de

The original JPEG V4 source is available from several ftp-servers.

Just enjoy it,

Lutz Vieweg


CHANGES:

4.2
    - oh no, sorry... the archive with 4.1 included
      the old 4.0 executables...
    - for consistency, CTRL-C is now used to abort
      djpeg in any case.

4.1 
    - now you can always stop djpeg with CTRL-C
      while decoding...
    - cjpeg changed: it uses now the multipic.library
      (supplied with the Retina Software 1.3 and up)
      to load the original picture, therefore any
      format supported by this library may be packed!
    - cjpeg now uses infile outfile syntax
      djpeg still writes on stdout by default.
    - cjpeg progess display enabled