It is DirectShow AC3 Decoder filter used to palyback AVI files with AC3 sound tracks and DVDs. Multichannel and S/PDIF support. Focused at flexible controls during playback: gains, mixer, stream information, levels and other.

The Irrlicht Engine is a high performance real-time 3D engine written and usable in C++, and also available for .NET languages. It is completely cross-platform, using D3D, OpenGL, and its own software renderers.

Anjuta is a versatile Integrated Development Environment (IDE) for C and C++ in GNU/Linux. It has been written for GTK/GNOME, and features a number of advanced programming facilities. These include project management, application wizards, an onboard interactive debugger, and a powerful source editor with source browsing and syntax highlighting....

Exult is an open-source game engine for playing Ultima7 on modern operating systems, using the game's original data files.

QGit is a graphical interface to git repositories, built on Qt/C++.

With qgit you will be able to browse revisions history, view patch content and changed files, graphically following different development branches.

re2c is a tool for writing very fast and very flexible scanners. Unlike any other such tool, re2c focuses on generating high efficient code for regular expression matching. As a result this allows a much broader range of use than any traditional lexer offers. And Last but not least re2c generates warning free code that is equal to hand-written code in terms of size, speed and quality....

cppcheck tries to detect bugs that your c/c++ compiler don't see.
It is versatile. You can check code that has non-standard code such as various compiler extensions, inline assembly code, etc.

mcrypt is a program for encrypting files or streams. It is intended to be a replacement for the old UNIX crypt. It uses well-known and well-tested algorithms like BLOWFISH, AES, ARCFOUR, CAST-128, and more in several modes of operation. It also has a compatibility mode with the old UNIX crypt program and the des program found in Solaris....

DCMTK is a collection of libraries and applications implementing large parts the DICOM standard. It includes software for examining, constructing and converting DICOM image files, handling offline media, sending and receiving images over a network connection, as well as demonstrative image storage and worklist servers. DCMTK is is written in a mixture of ANSI C and C++. It comes in complete source code and is made available as "open source" software....

LilyPond is a music typesetter. It produces beautiful sheet music using a description file as input. LilyPond is part of the GNU Project.