Mumble is an open-source, low-latency, high quality voice chat software.

qTox is a chat, voice, video, and file transfer IM client using the encrypted peer-to-peer Tox protocol.

WebRTC plugin for Flutter Mobile/Desktop/Web

Advanced repeater system software with EchoLink support for Linux including a GUI, Qtel - the Qt EchoLink client

Linphone is a free VoIP and video softphone based on the SIP protocol. Mirror of git://git.linphone.org/linphone-desktop.git

网关服务：Sip与Rtc互通，实现Web，Android，iOS，小程序，SIP座机，PSTN电话，手机互通。

TeamTalk 5 Development

Linphone.org mirror for flexisip (git://git.linphone.org/flexisip.git)

Minimalist Windows / OSx / Linux SIP Softphone with API Control

libice是一个c/c++库，它实现了RFC5245规范定义的交互式连接建立(ICE)协议, 适用于实时通信领域，比如音视频实时通信。

VoIP signaling and media test automation

H323Plus - H.323 development framework

Mumble VoIP Plugin and mod for the popular game "Among Us" to enable Proximity Voice Chat.

GNU Gatekeeper - H.323 server for VoIP and videoconferencing

C++ Qt Serverless Lan Messenger, Private Messages & Chat Rooms, Voice Talk

A simple SIP server (proxy) for handling VoIP calls based on SIP using C++ on Windows & Linux platforms.

Silent is very lightweight, high quality - low latency voice chat for gaming. The server runs on Windows and Linux.

A Native Implementation of Telegram Calls in a seamless way.

High performance P2P-Mesh video conferencing

Platform-independent voice-over-IP peer-to-peer communication program