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PJSIP

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Velocity0.0

Open-source multimedia communication library for SIP, SDP, RTP and STUN

www.pjsip.org ↗

A mature SIP stack turns its attention to concurrency correctness and AI voice endpoints

sipvoipmedia-stackconcurrencyai-voiceembedded
◆Current state
PJSIP remains the reference open-source SIP and media stack for embedded and mobile softphones, shipping roughly one feature release a year. Version 2.17 pairs asynchronous client authentication with a documented real-time AI speech connectivity path, alongside ten separate deadlock fixes. The cadence is slow, but each drop carries a backward-incompatibility section integrators have to read before upgrading.
◆Where it's heading
The arc from 2.14 to 2.17 moves away from platform and codec breadth — IPv6 dual stack, a Metal renderer, Lyra, a Schannel TLS backend — and toward the harder problem of concurrency inside the media core: async conference bridge operations, then parallel bridging, then async authentication and systematic deadlock elimination. AI speech connectivity in 2.17 is the first indication the project treats voice agents, not only human callers, as a target workload. The growing list of API breaks suggests the maintainers will trade source compatibility for cleaner threading semantics.
◆Prediction
Expect the next release to widen the AI speech path with more transport and codec options while continuing to convert blocking media-core calls to asynchronous ones.

◆Recent moves

  1. 3mo ago

    PJSIP 2.17 adds async SIP auth and AI speech connectivity

    ⚡ SPARK

    The most directional release in the window: asynchronous client authentication and an AI real-time speech path land together, on top of ten deadlock fixes. It continues the concurrency-hardening arc while opening a workload the stack was not previously built for.

    View source ↗
  2. 8mo ago

    PJSIP 2.16 brings real-time text and a parallel conference bridge

    Real-time text (RFC 4103), a parallel conference bridge and audio/video synchronization broaden what the stack can carry without changing its direction. The parallel bridge is the one that matters for the arc, extending the media-core concurrency work started in 2.15.

    View source ↗
  3. 1y ago

    PJSIP 2.15 adds Metal rendering, Schannel TLS and the Lyra codec

    Platform breadth: a Metal renderer for Mac and iOS, a Windows Schannel TLS backend, the Lyra codec and client-side dialog event subscription. It also makes conference bridge operations asynchronous, which is where the port-lifetime caveats and the concurrency arc begin.

    View source ↗
  4. 1y ago

    PJSIP 2.15.1 fixes auth and async conference bridge bugs

    A point release cleaning up the authentication and async conference bridge work introduced weeks earlier in 2.15. Corrective only.

    View source ↗
  5. 2y ago

    PJSIP 2.14.1 fixes an ICE deadlock and re-INVITE handling

    Three fixes — a stream/ICE deadlock, re-INVITE answering and a transport loop. Early evidence of the deadlock work that becomes a headline item by 2.17.

    View source ↗
  6. 2y ago

    PJSIP 2.14 adds dual-stack IPv6 and mobile sample apps

    IPv4/IPv6 dual-stack account configuration plus video sample apps across Android, iOS and Xamarin — reach work aimed at getting the stack adopted on mobile. Representative of the breadth phase that precedes the concurrency focus.

    View source ↗