Linphone licensing
Linphone, liblinphone, mediastreamer2 are provided under the GNU GPL v2 license. You can use and distribute freely this software. If you integrate it within a larger software, this software must be GPL too.
oRTP, (the RTP library) is provided under the GNU LGPL v2 license.
For proprietary licenses, please consult Belledonne Communications, the company sponsoring the linphone project.