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Thoughts about the GIF/LZW question



The following are my believings about the GIF question. I made up
them acquiring information from different sources but hardly from
"official" ones.

AFAIK, the whole problem with GIFs and TIFFs is: the LZW algorithm
used to compress them is patented (probably in the US only); a free
of charge licence is automatically granted for decompressors; nothing
good about compression.

My considerations:

1) Any package, sitting in non-free only because of this (or any other)
patent issue, should go to non-US/main or non-US/contrib as appropriate;
if it has a non-free licence plus patent problems, it should probably
go to non-US/non-free.
The back idea here is that the distinction between free, free depending
on non-free (i.e. contrib, which is a poor name for that) and non-free
should be based on copyright license only; other issues like patents,
export restrictions, import restrictions, trademarks and whatever,
should be treated orthogonally.

1a) It is my (ineducated) opinion that a patent does restrict _use_ of
the software or algorithm or whatever it applies to, and it does not
restrict copy, modification and distribution of it. I mean, an
industrial process patent restricts implementing the process, which
in software means "running the program". Am I wrong?

2) LZW was published in 1978 (right?); when was it patented? when will
the patent expire? did Lempel, Ziv and Welch work for Unisys? is the
patent general enough to include any LZW-style compression algorithm
or is it narrow enough to include only 12-bit coding applied to bitmaps?

3) The archive is inconsistent about GIF/TIFF manipulating packages;
results from a quick search on Packages.gz on slink CDs:

* in main:
g2 - "gif support removed because it depends on a non free library"
giftrans - write gif
libgd1g - write gif
libgd1g-dev - write gif
libtiff3g - write tiff?
libtiff3g-dev - write tiff?
mrtg - write gif?
plplot-tcl - write gif?
webmagick - write gif?

The gif/tiff-writing packages should go to non-US/main, IMO.
Does libtiff3g include the capability to write LZW-compressed TIFFs?
If it does, it should be split in a similar way to giflib/libungif.

* in non-free:
Package        Why non-free
gfont        - write gif
gif2png      - read gif
giflib-bin   - depend on giflib3g 3.0-5.2
giflib3g     - write gif
giflib3g-dev - write gif
gimp-nonfree - write gif, depends on libtiff
libgd-perl   - write gif?
whirlgif     - write gif
xanim        - write gif
xearth       - write gif

gif2png should go to main if it's otherwise free; the gif-writing
packages should go to non-US/something as appropriate according to
their copyright license.

Ciao, William


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