PJSIP is a free and open-source multimedia communication library written in C language implementing standard-based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. It combines signaling protocol (SIP) with a rich multimedia framework and NAT traversal functionality into high-level API that is portable and suitable for almost any type of system ranging from desktops, and embedded systems, to mobile handsets. PJSIP is both compact and feature rich. It supports audio, video, presence...