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Diffstat (limited to 'doc/COPYRIGHT.PATENT')
| -rw-r--r-- | doc/COPYRIGHT.PATENT | 93 |
1 files changed, 4 insertions, 89 deletions
diff --git a/doc/COPYRIGHT.PATENT b/doc/COPYRIGHT.PATENT index fe3c242a..24b1583a 100644 --- a/doc/COPYRIGHT.PATENT +++ b/doc/COPYRIGHT.PATENT @@ -34,92 +34,7 @@ all the above to be modified by "to the best of the Netpbm maintainer's knowledge." - -PATENTS -------- - -These are the patents the Netpbm maintainer knows about that relate to -Netpbm. It is basically just information the maintainer has stumbled -over at some point -- no search has been done. - -No licenses have been granted by patent owners to the maintainer of -Netpbm. Therefore, if you need a patent to use something in Netpbm, -you need your own license. - -A note about patents in general: A patent gives an inventor the -exclusive right to make, sell, or use the invention. If you -independently invent something without knowing that the patent holder -already did, that makes no difference -- the patent holder still has -the exclusive right. It makes no difference if you give the original -inventor credit. The patent applies to a method, not its expression, -so writing a program from scratch to implement a certain method is -still a patent infringement. Infringing a patent is not a crime per -se, but to the extent that it costs the patent holder money, the -infringer has to make it up. - -The original purpose of patents is probably perverted when patents are -applied to things you implement in computer programs. This is one of -the Free Software Foundation's causes. See -<http://www.gnu.org/philosophy.html#laws>. - - -Unisys owns patents on LZW compression, which is used by Ppmtogif, and -maybe on LZW decompression, which is used by Giftopnm. IBM also owns -a patent that may cover the GIF tools. Unisys offers a license of the -patent for trivial use for $5000. Its U.S. patent (Number 4,558,302) -EXPIRED June 20, 2003. In most of Europe, the patent expires June 18, -2004. In Japan, it's June 20, 2004 and in Canada, July 7, 2004. -IBM's U.S. patent expirs August 11, 2006. - -Neither company has ever enforced the patent against trivial users of -it. <http://news.cnet.com/news/0-1005-200-1713278.html> is an article -dated April 18, 2000 on the issue. -http://www.unisys.com/about__unisys/lzw/> is Unisys' view of the -matter. For information from another perspective, see -<http://burnallgifs.org>. - -The following Netpbm components may be restricted by these patents: -Ppmtogif, Giftopnm. - -A good substitute for GIF if the patents are a problem is PNG (see -pngtopnm, pnmtopng), which was developed with a primary purpose of not -using any patented technology. - -You can also use the -nolzw option on ppmtogif to avoid using the LZW -patent. The images so generated are larger than traditional -LZW-compressed GIFs, but any GIF decoder can decode them just the -same. - -I repeat: The Unisys U.S. patent has expired. It is not an issue -for any future use of Netpbm. - - -The Pnmtojpeg and possibly Jpegtopnm programs in some cases may use -the arithmetic coding patents owned by IBM, AT&T, and Mitsubishi. -There is difference of opinion on whether they do. - -Forgent owns a patent it believes covers JPEG compression. This -patent was virtually unknown before July 2002, when Forgent began to -enforce it. It has successfully enforced it against two companies -(Sony and an unnamed Japanese digital camera maker), but without court -ruling. This patent, U.S. Patent No. 4,698,672, expires in 2006. - -Philips and Lucent Technologies also own patents they claim cover -JPEG. - -The following Netpbm components may be restricted by these patents: -Jpegtopnm, Pnmtojpeg, Ppmtompeg, Tifftopnm, Pnmtotiff. These all -do their JPEG work via a JPEG library not distributed with Netpbm. -Your JPEG-related liability for using Netpbm is limited to your -liability for using your JPEG library. - -The next best alternative to JPEG is probably PNG and maybe JBIG for -bilevel (black and white) images. - -http://burnalljpegs.org contains information on this issue. - - -The Jbigtopnm and Pnmtojbig programs use arithmetic coding patents and -other patents covering various aspects of the "front end." - - +Netpbm may practice valid patents, which would mean that you owe someone +royalties if you use the code. This is a miniscule risk, though. +What is known about patents related to Netpbm is in the file +'doc/patent_summary' in the Netpbm source tree. |