The first thing to do when making a new element is to specify some basic details about it: what its name is, who wrote it, what version number it is, etc. We also need to define an object to represent the element and to store the data the element needs. I shall refer to these details collectively as the boilerplate. The standard way of defining the boilerplate is simply to write some code, and fill in some structures. The easiest way to do this is to copy an example and modify according to your needs. First we will examine the code you would be likely to place in a header file (although since the interface to the code is entirely defined by the pluging system, and doesn't depend on reading a header file, this is not crucial.) The code here can be found in examples/plugins/example.h /* Definition of structure storing data for this element. */ typedef struct _GstExample GstExample; struct _GstExample { GstElement element; GstPad *sinkpad,*srcpad; gint8 active; }; /* Standard definition defining a class for this element. */ typedef struct _GstExampleClass GstExampleClass; struct _GstExampleClass { GstElementClass parent_class; }; /* Standard macros for defining types for this element. */ #define GST_TYPE_EXAMPLE \ (gst_example_get_type()) #define GST_EXAMPLE(obj) \ (GTK_CHECK_CAST((obj),GST_TYPE_EXAMPLE,GstExample)) #define GST_EXAMPLE_CLASS(klass) \ (GTK_CHECK_CLASS_CAST((klass),GST_TYPE_EXAMPLE,GstExample)) #define GST_IS_EXAMPLE(obj) \ (GTK_CHECK_TYPE((obj),GST_TYPE_EXAMPLE)) #define GST_IS_EXAMPLE_CLASS(obj) \ (GTK_CHECK_CLASS_TYPE((klass),GST_TYPE_EXAMPLE)) /* Standard function returning type information. */ GtkType gst_example_get_type(void); A plan for the future is to create a FilterFactory, to make the process of making a new filter a simple process of specifying a few details, and writing a small amount of code to perform the actual data processing. Unfortunately, this hasn't yet been implemented. It is also likely that when it is, it will not be possible to cover all the possibilities available by writing the boilerplate yourself, so some plugins will always need to be manually registered. As a rough outline of what is planned: the FilterFactory will take a list of appropriate function pointers, and data structures to define a filter. With a reasonable measure of preprocessor magic, the plugin writer will then simply need to provide definitions of the functions and data structures desired, and a name for the filter, and then call a macro from within plugin_init() which will register the new filter. All the fluff that goes into the definition of a filter will thus be hidden from view. Ideally, we will come up with a way for various FilterFactory-provided functions to be overridden, to the point where you can construct almost the most complex stuff with it, it just saves typing. Of course, the filter factory can be used to create sources and sinks too: simply create a filter with only source or sink pads. You may be thinking that this should really be called an ElementFactory. Well, we agree, but there is already something else justifiably ealled an ElementFactory (this is the thing which actually makes instances of elements). There is also already something called a PluginFactory. We just have too many factories and not enough words. And since this isn't yet written, it doesn't get priority for claiming a name.