DirectFB is a thin library that provides developers with hardware graphics acceleration, input device handling and abstraction, an integrated windowing system with support for translucent windows and multiple display layers on top of the Linux framebuffer device. It is a complete hardware abstraction layer with software fallbacks for every graphics operation that is not supported by the underlying hardware.
Audiality is a highly scalable and portable audio engine and synthesizer. MIDI files are used in combination with scripting and modular synthesis, to minimize file sizes and maximize flexibility. Audiality can be used as a music and sound effects player in multimedia productions, or as a realtime MIDI synthesizer.
Csound is a powerful and yet easy to use musical synthesis package. Csound was constructed in the tradition of so-called music-N languages, among which the best-known is Music V. It consists of an orchestra- and score-driven executable, written in C for portability. Since Csound is a computational language, it is highly flexible and efficient; complexity is gained only at the expense of computation power. Basically, Csound reads some files and creates the result as a sound file on disk or, on faster machines, in real time through a DAC.
Pakt is an XML abstraction layer for GObjects. It maintains a server-side tree of glib-like (Gtk, Gnome, etc) objects and provides access methods to manipulate the same (and thereby the running 'application'). Its primary use is to publish GStreamer pipelines, enabling connected clients to monitor and change the element's parameters and the pipeline's structure.
"Tegel" is an add-on for Allegro for drawing and handling layered tilemaps. The package contains an editor and a playback library in C. There is support for multiple layers and rotated and/or animated tilemaps. The editor is easy to use, with unlimited undo, copy/paste, flood fill, and help included.