I am getting conflicting information on the exact license of x265. readme.rst, COPYING, and x265.org all point to the information that x265 is available exclusively under GPL version 2 or the commercial license. However, all of the source files have the following header:
/* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */
Note that even if the original intention was version 2 only, it's probably too late anyway, since the license header has been here for almost 3 years now.