JPEG2DCTV Version 0.7

This is a quick and dirty program to decompress JPEG compressed
images into a DCTV display buffer.  It takes about one minute to
decompress a 730 x 482 x 24 bit image to a full DCTV NTSC screen
on an Amiga 3000 with 'jpeg2dctv', and about 40 seconds with
'jpeg2dctv.030'(68030 version), both of which are included.

After the program is finished decoding, you may save the DCTV image
by typing in a filename; 'jpeg2dctv' will save the image and exit.
If you do not want to save the image, just hit return when prompted
to exit 'jpeg2dctv'.

This software is provided AS IS.
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Updates from v. 0.6:
   - fixed bug in decoding grayscale JPEG files.  Formerly, the machine
     would lock or crash if a grayscale JPEG file was encountered.

Updates from v. 0.5:
   - added support for PAL DCTVs.  Updated the scaling algorithm,
     aspect ratio algorithm and centering algorithm to support PAL displays.

Updates from v. 0.4:
   - substituted 'ilbm.library' for the EA IFF-ILBM saving code.  The
     result is that you no longer need to change the stack size under
     2.0.  Also, the saving is much faster.
   - added a command line option to change the aspect ratio of a JPEG
     file to better fit an Amiga screen.  NTSC Amiga pixels are 1.2 times
     taller than they are wide.  PAL Amiga pixels are 1.07 times wider
     than they are tall.  Most JPEG images created on other
     machines will have square pixels.  The '-a' option removes lines
     from a JPEG file on an NTSC display and adds lines on a PAL display,
     so that the image will appear square on the DCTV screen will look
     better on either PAL or NTSC machines.
     Check the effect of the '-a' option on 'testimg.jpg'.

Updates from v. 0.3:
   - added ability to save the created DCTV image; and
   - added a command line option to deactivate auto-scaling. Instead,
     'jpeg2dctv' will now take the center 736x482 (NTSC) or
     736x566 (PAL) from the JPEG file, and output the center of the 
     JPEG file as a DCTV image.  This was added because the scaling
     algorithm is basic, and will cause jaggies if the JPEG input file is
     only slightly bigger than 736 horizontally or 482 vertically (NTSC)
     or 566 vertically (PAL).

Updates from v. 0.2:
   - will scale down a JPEG file larger than the DCTV display
     to fit on a DCTV screen; and
   - task priority may be set with the '-p' command line switch
     from -127 to 0 (default is -10).  'jpeg2dctv' is processor
     intensive, and a priority of >0 makes my Amiga
     appear to be frozen.

Updates from v. 0.1:
   - added proper overscan support;
   - now both 1.3 and 2.0 compatible;
   - screen pops to front when finished decoding; and
   - improved control-c handling
     (will not break until after it is finished decoding).

-Benjamin Reich
                   Portal:  Counsellor
                   BIX:     ben_rich
                   Delphi:  BEN_RICH
                   Usenet:  Counsellor@cup.portal.com

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
-rw-rw-r-- 20025/206      5238   10224  51.2% -lh5- 33bb Nov  9  1991 dctv.library
-rw-rw-r-- 20025/206      5041    6924  72.8% -lh5- f100 Nov  9  1991 ilbm.library
-rw-rw-r-- 20025/206     21902   40896  53.6% -lh5- 095a Feb 19  1992 jpeg2dctv
-rw-rw-r-- 20025/206     21596   39916  54.1% -lh5- dba8 Feb 19  1992 jpeg2dctv.030
-rw-rw-r-- 20025/206      1862    4297  43.3% -lh5- f83c Feb 19  1992 jpeg2dctv.readme
-rw-rw-r-- 20025/206      3379    3583  94.3% -lh5- 8435 Nov  7  1991 testimg.jpg
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         6 files   59018  105840  55.8%            Jun 18  1992