Re: MP4/8 Prism Conversion (description)

[snakey@destiny.dorm.umd.edu (David Ross)]

Frank M. Lin (fmlin@ccnet.com) wrote:
: In article <Z+w306W.shinyan@delphi.com>,
: Shinya Nagashima  <shinyan@delphi.com> wrote:
: >I know there has been quite a lot of discussion concerning GS graphic
: >converters, but few people have mentioned Prism GS by New Concepts. And I'm
: >sure that those who have at least heard of the program may have wondered how
: >it stacks up against SuperConvert and freeware/shareware alternatives.

I've found that the best way to process pictures is to use the GS as 
little as possible.  :(  It's pretty obvious that if you have a picture 
formatted exatly how IFF2GS likes it, IFF2GS can do one hell of a job on 
conversion.  The problem is, how to get it that way.  Unfortunately, no 
GS utility that I have seen does a good job of converting, scaling, 
cropping, etc., because they all insist on not working with the raw, 
possibly 24 bit, image.  

There is a wonderful set of unix utilities which does a really nice job 
of manipulating images, and can even write IFF files!  You need a nice 
UNIX shell account to do this from, but here is the alias that I put in 
my .cshrc file...  (actually two)

alias gififfsend "giftoppm < \!:1 | pnmcrop | pnmcrop -white | pnmcrop 
-black | pnmscale -xysize 320 200 | ppmquant -fs 4096 > tempppm; ppmmake 
rgbi:0/0/0 320 200 > tempppm2; pnmpaste tempppm 0 0 tempppm2 | ppmtoilbm 
-hamif > \!:2; rm -rf tempppm tempppm2 \!:1 ; sz -bu \!:2"

alias jpegiffsend "djpeg -pnm < \!:1 | pnmcrop | pnmcrop -white | pnmcrop 
-black | pnmscale -xysize 320 200 | ppmquant -fs 4096 > tempppm; ppmmake 
rgbi:0/0/0 320 200 > tempppm2; pnmpaste tempppm 0 0 tempppm2 | ppmtoilbm 
-hamif > \!:2; rm -rf tempppm tempppm2 \!:1 ; sz -bu \!:2"

Now, the command "gififfsend picture.gif picture.iff" will basically send 
me, picture.gif, but converted to an iff.  It doesn't just convert it 
though.  First it crops out the main part of the picture (removes any 
blank lines on any sides), then it resizes it so that it is either 320 
pixels wide, 200 pixels high, or both, so that the aspect ratio remains 
correct.  Then it pastes that picture onto a black picture that is 
exactly 320x200, so that the whole picture itself is 320x200.  Then it 
cuts the colors down to 4096 (that can be adjusted, but I just wanted to 
make ppmquant to most of the "quant"ing because just a plain "ppmtoilbm 
-hamif" won't do any floyd-stienberg dithering.  (The good kind, not the 
ugly kind.)  The picture comes out as an iff, and is sent with zmodem.  
Both copies are deleted on the remote computer.  The other command that I 
made does the same thing, but with jpegs.  Have fun, and let me know if 
you know of a way to get even better results!

Dave Ross