GStreamer Daemon, also called gstd, is a GStreamer framework for controlling audio and video streaming using TCP connection messages. Qt applications, web interfaces, and GStreamer element test suites show different ways the framework can be utilized. GStreamer Daemon is gst-launch on steroids where you can create a GStreamer pipeline, play, pause, change speed, skip around, and even change element parameter settings all while the pipeline is active.
GStreamer Daemon is designed for production deployment, where the control logic runs in a separate process for the audio video streaming server. The control application can be written in any language, does not need to use gobject / glib, as long as data can be exchanged over a TCP connection. The control application can run on the same processor (using localhost for the TCP destination) or a separate machine. Isolating the control logic from the streaming logic solves many difficult problems, from setting priorities to avoid audio drop out to having a working user interface if the streaming application encounters corrupt data. By separating the audio video streaming logic, it is easy to create automated A/V tests, extend a product's features to support remote control, and allow the control application the streaming daemon to be developed independently.
The official documentation is held in RidgeRun Developer's Wiki.