Liblinphone SDK

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Liblinphone is a high-level open source library that integrates all the SIP-based voice/video calling, conferencing and instant messaging features into a single easy-to-use API.

This is the VoIP SDK engine on which Linphone applications are based!

Liblinphone combines our media processing and streaming toolkit (Mediastreamer2) with our user-agent library for SIP signaling (belle-sip).

Signaling features : 

  • user authentication via digest (SHA256 or md5) and TLS client certificates
  • multiple call management: hold, resume, transfer and more
  • multiple SIP proxy support: registrar, proxies, outbound proxies
  • presence using list subscription to presence server
  • DTMF (telephone tones)
  • interoperability with IMS networks
  • suitable for building a VoLTE-compatible client

Media features :

  • HD audio calls with support for Opus codec
  • HD video calls with support for H.264, H.265 and VP8 codecs  
  • state-of-the-art adaptive jitter buffer algorithm
  • innovative adaptive bitrate control
  • ICE support for optimised NAT traversal
  • end-to-end media encryption using SRTP, SRTP-DTLS and ZRTP protocols
  • post quantum encryption using Crystals-Kyber algorithm
  • audio and video call recording

Instant Messaging features :

  • one-to-one and group instant messaging
  • ephemeral messaging
  • voice/video messaging
  • delivery and "is typing" notifications
  • end-to-end encryption for one-to-one and group conversations
  • file sharing, with configurable settings to automatically / manually download attachments

Consult our technical corner to see the list of supported standards, download pre-compiled binaries or the SDK source code, and find more information about available tutorials and documentation.

Technical corner