LZW – that is, the formerly patented Lempel-Ziv Welch compression algorithm – is free today. The footnote on the Free Software Foundation’s GIF history page says:
The Unisys patent expired on 20 June 2003 in the USA, in Europe it expired on 18 June 2004, in Japan the patent expired on 20 June 2004 and in Canada it expired on 7 July 2004. The U.S. IBM patent expired 11 August 2006, The Software Freedom Law Center says that after 1 October 2006, there will be no significant patent claims interfering with employment of the GIF format.
(Emphasis mine.) The patent they’re referring to there is of course on LZW compression, not on GIF89a itself. LZW is used in other things, like TIFF compression, and, uh, V.42bis modems.
Once I understood the algorithm (David Mertz’s Text Processing in Python has a good explanation of how it works), I thought, hey, that’s really clever. Then I thought: that is what Unisys has been milking for patent royalties all these years?
I propose that today, October 1, become known as International Freedom From Stupid Software Patents Day. Let’s celebrate.
James commented on Mon Oct 2 10:32:36 2006:
Then I thought: that is what Unisys has been milking for patent royalties all these years?
Isn’t inertia great? There really hasn’t been any reason to use GIF for years – PNG is better. The same issue exists with MP3 – lossless formats with an open standard exist, but not enough people use them to change the defacto standard.
Jessica commented on Wed Oct 4 10:15:24 2006:
“There really hasn’t been any reason to use GIF for years PNG is better.”
Why is PNG better?
Roy commented on Mon Jan 22 17:17:37 2007:
IE can’t handle pages that are actually W3 compliant code either.
It’s IE that is crap…. not PNG
IE is another example of Inertia.