The GStreamer multimedia framework and the accompanying GNonLin set of plugins for non-linear editing offer all the building blocks for:
Decoding and encoding to a wide variety of formats, through all the available GStreamer plugins.
Easily choosing segments of streams and arranging them through time through the GNonLin set of plugins.
But all those building blocks only offer stream-level access, which results in developers who want to write non-linear editors to write a consequent amount of code to get to the level of non-linear editing notions which are closer and more meaningful for the end-user (and therefore the application).
The GStreamer Editing Services (hereafter GES) aims to fill the gap between GStreamer/GNonLin and the application developer by offering a series of classes to simplify the creation of many kind of editing-related applications.