This chapter gives you an overview of the technologies described in this book. &GStreamer; is a framework for creating streaming media applications. The fundamental design comes from the video pipeline at Oregon Graduate Institute, as well as some ideas from DirectShow. &GStreamer;'s development framework makes it possible to write any type of streaming multimedia application. The &GStreamer; framework is designed to make it easy to write applications that handle audio or video or both. It isn't restricted to audio and video, and can process any kind of data flow. The pipeline design is made to have little overhead above what the applied filters induce. This makes &GStreamer; a good framework for designing even high-end audio applications which put high demands on latency. One of the the most obvious uses of &GStreamer; is using it to build a media player. &GStreamer; already includes components for building a media player that can support a very wide variety of formats, including MP3, Ogg/Vorbis, MPEG-1/2, AVI, Quicktime, mod, and more. &GStreamer;, however, is much more than just another media player. Its main advantages are that the pluggable components can be mixed and matched into arbitrary pipelines so that it's possible to write a full-fledged video or audio editing application. The framework is based on plugins that will provide the various codec and other functionality. The plugins can be linked and arranged in a pipeline. This pipeline defines the flow of the data. Pipelines can also be edited with a GUI editor and saved as XML so that pipeline libraries can be made with a minimum of effort. The &GStreamer; core function is to provide a framework for plugins, data flow and media type handling/negotiation. It also provides an API to write applications using the various plugins. This book is about &GStreamer; from a developer's point of view; it describes how to write a &GStreamer; application using the &GStreamer; libraries and tools. For an explanation about writing plugins, we suggest the Plugin Writers Guide. In order to understand this manual, you will need to have a basic understanding of the C language. Since &GStreamer; adheres to the GObject programming model, this guide also assumes that you understand the basics of GObject programming. You may also want to have a look at Eric Harlow's book Developing Linux Applications with GTK+ and GDK. In addition you might want to read the &GstPWG; after this manual. Also check out the other documentation available on the &GStreamer; web site. To help you navigate through this guide, it is divided into several large parts. Each part addresses a particular broad topic concerning &GStreamer; appliction development. The parts of this guide are laid out in the following order: gives you an overview of &GStreamer;'s motivation design goals. rapidly covers the basics of &GStreamer; application programming. At the end of that chapter, you should be able to build your own audio player using &GStreamer; In , we will move on to complicated subjects which make &GStreamer; stand out of its competitors. We will discuss application-pipeline interaction using dynamic parameters and interfaces, we will discuss threading and threaded pipelines, scheduling and clocks (and synchronization). Most of those topics are not just there to introduce you to their API, but primarily to give a deeper insight in solving application programming problems with &GStreamer; and understanding their concepts. Next, in , we will go into higher-level programming APIs for &GStreamer;. You don't exactly need to know all the details from the previous parts to understand this, but you will need to understand basic &GStreamer; concepts nevertheless. We will, amongst others, discuss XML, playbin and autopluggers. In , you will find some random information on integrating with GNOME, KDE, OS X or Windows, some debugging help and general tips to improve and simplify &GStreamer; programming.