Overview and architecture
1
GStreamer Editing Services

## Goals of GStreamer Editing Services

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
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.

## Architecture

### Timeline and TimelinePipeline

The most top-level object encapsulating every other object is the GESTimeline. It is the central object for any editing project.

The `GESTimeline` is a `GstElement`. It can therefore be used in any GStreamer pipeline like any other object.

### Tracks and Layers

The GESTimeline can contain two types of objects (seen in ):

- Layers - Corresponds to the user-visible arrangement of clips, and what you primarily interact with as an application developer. A minimalistic timeline would only have one layer, but a more complex editing application could use as many as needed.

- Tracks - Corresponds to the output streams in GStreamer. A typical GESTimeline, aimed at a video editing application, would have an audio track and a video track. A GESTimeline for an audio editing application would only require an audio track. Multiple layers can be related to each track.

#### Layers and Tracks

In order to reduce even more the amount of GStreamer interaction the application developer has to deal with, a convenience GstPipeline has been made available specifically for Timelines : GESPipeline.