This a mediastreamer2 plugin adding support for AMR codec.
It is known to work with linphone>=3.0.0
It is based on the opencore-amr implementation:
http://sourceforge.net/projects/opencore-amr/
You must first download, compile and install opencore-amr, then build the msamr plugin.
The source code of opencore-amr can be found at http://sourceforge.net/projects/opencore-amr/files/opencore-amr/0.1.2/opencore-amr-0.1.2.tar.gz
when compiling with mingw (for windows), remove .la files from your installation directory where you previously installed opencore-amr.