| # License Secret Rabbit Code is released under a dual licensing scheme. Users can choose which of these two licenses they wish to operate under : The standard GNU General Public License (GPL) as written and published by the Free Software Foundation. The very generous libsamplerate Commercial Use License that can be purchased for a one off payment of $1000 (one thousand) Australian dollars. Any person or organisation wishing to distribute (either privately or publicly) software which uses Secret Rabbit Code must either abide by the GPL or purchase a commercial use license. The commercial use license allows licensees to use libsamplerate as a statically linked library in proprietary, shareware or other closed source applications. The licensee may use libsamplerate in as many separate products as they choose and sell as many copies of each as they can without paying any further licensing fees for libsamplerate. 2005-08-09 : There is a certain amount of debate about whether non-GPL software can dynamically link to GPL libraries. I side with the FSF and assert that an executable dynamically linked to libsamplerate is a derivative work of libsamplerate and is therefore subject to the GNU GPL. For more information, please see the commercial use licensing procedure .