rubberband

Rubber Band Library is a high quality software library for audio time-stretching and pitch-shifting. It permits you to change the tempo and pitch of an audio stream or recording dynamically and independently of one another. Rubber Band Library is open source software under the GNU General Public License. If you want to distribute it in a proprietary commercial application, you need to buy a license. This is a binding to Rubber Band Library v1.8.1.