It is said the patents on arithmetic coding expired in 2009, although I don't have a definite source for that but I'm sure such could be found with some rigorous browsing. But I doubt that, for instance, Independent JPEG Group's libjpeg project and the libjpeg-turbo fork would feature arithmetic coding these days if it weren't patent-free. Anyway, just something for the future maybe

To play it safe, it might be worthwhile to wait and see what Fedora does:
http://www.mail-archive.com/devel@lists ... 16146.html.