The correct way to include a certain QtGStreamer header for a class is to use the #include <namespace/class> syntax. For example:
All the other lowercase headers (which all end with .h) are considered private and should not be used directly.
Nearly all the C objects that these bindings wrap are reference counted. This means that when you obtain a pointer to such an object, you need to increase its reference count value and decrease it when you no longer need that pointer. To make reference counting easy, QtGStreamer wraps all those objects in a smart pointer class, RefPointer. This smart pointer does all the reference counting work for you and you do not need to worry about it at all.
To offer a nice syntax, all those wrapper classes additionally offer typedefs for RefPointer, in the form:
typedef RefPointer<WrapperClass> WrapperClassPtr;