Scenes are the basic building blocks of Templates. Scenes are like short clips of video that are played sequentially. Each scene has its own timeline. A regular scene includes multiple layers that represent components such as video and audio items, animated text and vector graphics, still images, and other items. You then arrange layers within a scene in space and time, and composite using transparency features to determine which parts of underlying layers show through the layers stacked on top of them. (See Layers and properties and Transparency and compositing.).
The duration of scenes is either provided in the duration attribute, or is determined by the content of the scene. For the special case that the length of scene is determined by the audio and not the visual content, you can specify "audio" in the "duration" attribute of a scene.
To create dynamic story flows, a scene may be optional, i.e it will only be rendered if a certain condition is met. "Choice" scenes will render a scene out of a selection of scenes determined by a variable that can be different for each render request.
Because scenes are rendered in parallel, you should try to split your template into multiple scenes to reduce render time.
<scene type="regular | optional | choice" duration="xs:integer | audio" background="xs:string" condition="xs:string" case="xs:string" > . . . </scene>
|regular||The scene is always rendered|
|optional||The scene is only rendered if the condition evaluates to true|
|choice||The scene to be rendered is determined by the condition variable and choosen among the <scene case="..."> children of this element.|