FFmpeg is the leading multimedia framework, able to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created. It supports the most obscure ancient formats up to the cutting edge.

Liboop is a low-level event loop management library for POSIX-based operating systems. It supports the development of modular, multiplexed applications which may respond to events from several sources. It replaces the "select() loop" and allows the registration of event handlers for file and network I/O, timers and signals. Since processes use these mechanisms for almost all external communication, liboop can be used as a basis for almost any application.

This is the Swedish-Dutch dictionary from the FreeDict project. It contains 10591 headwords (FreeDict status: big enough to be useful). It can be either used with the dictd server and a dict client or with GoldenDict.

This is the Polish-Bulgarian dictionary from the FreeDict project. It contains 10093 headwords (FreeDict status: big enough to be useful). It can be either used with the dictd server and a dict client or with GoldenDict.

The Mobile Robot Programming Toolkit (MRPT) is an extensive, cross-platform, and open source C++ library aimed to help robotics researchers to design and implement algorithms in the fields of Simultaneous Localization and Mapping (SLAM), computer vision, and motion planning (obstacle avoidance).

librandombytes is a public-domain library providing a simple API for applications generating fresh randomness: include <randombytes.h>, call randombytes(x, xbytes) whenever desired to generate fresh random bytes x[0], x[1], ..., x[xbytes-1], and link with -lrandombytes.