baresip is a bare-bones SIP user agent. It supports SIP, SDP, RTP/RTCP, and STUN/TURN/ICE, and IPv4 and IPv6, and is RFC-compliant and has portable C89 and C99 source code. A modular plugin architecture provides stdio, cons, and evdev user interfaces, celt, g711, g722, gsm, ilbc, l16, and speex audio codecs, alsa, coreaudio, gst, portaudio, oss, winwav, and mda audio drivers, speex_pp, speex_aec, speex_resamp, and sndfile audio filters, the avcodec video codec, avformat, quicktime, qtcapture, v4l, and v4l2 video sources, sdl, opengl, and x11 video display drivers, and srtp media encoding.
The Kowalski project aims to provide a data driven, lightweight cross platform audio solution. The target audience is developers of games and similar applications where real time audio plays an important role. The Kowalski engine, which is the runtime component, relies only on host-specific external libraries to pass the final output buffers to the audio hardware. All other processing is done in the engine code. Features include positional audio (distance attenuation, cone attenuation, Doppler shift, binaural panning), real time Ogg Vorbis decoding, a powerful mix bus system, and tools to build, validate, and view Kowalski data.
The Open-Transactions project is a collaborative effort to develop a robust, commercial-grade, fully-featured, free-software toolkit implementing a full-strength financial cryptography library, API, CLI, and prototype server. Open-Transactions democratizes financial and monetary actions. You can use it for issuing currencies/stock, paying dividends, creating asset accounts, sending/receiving digital cash, writing/depositing cheques, cashier's cheques, creating basket currencies, trading on markets, scripting custom agreements, recurring payments, escrow, etc. Strong crypto is used. Balances are unchangeable (even by a malicious server). Receipts are destructible and redundant. The transactions are unforgeable. The cash is untraceable. The cheques are non-repudiable.
Horology is a date/time calculator that supports all the built-in calendars for iOS, and allows you to perform various types of calculations or conversions of date and time values. You can find the difference between two date/time values, calculate a date/time by inputting a start date/time and add or subtract some arbitrary amount, or convert a value from one unit type to another (e.g., years to seconds).
ReplicaNet is an object oriented C++ library for developers of applications that require a stable and low maintenance middleware solution to networking. Any project that is designed to use a network of machines, such as multiplayer computer games, need to very carefully consider how to approach the design problems associated with networking. It includes support for binary difference patch creation and delivery, backend availability and TitleID verification, Internet CD/license key verification, NAT detection, advertising and querying of sessions, user accounts, friends lists, game invites, chat rooms, persistent data storage, and statistics and ranking.