| ElementExclusiveTimeContainer | This interface defines a time container with semantics based upon par, but with the additional constraint that only one child element may play at a time. |
| ElementLayout | This interface is used by SMIL elements root-layout, top-layout and region. |
| ElementParallelTimeContainer | A parallel container defines a simple parallel time grouping
in which multiple elements can play back at the same time. |
| ElementSequentialTimeContainer | A seq container defines a sequence of elements in which
elements play one after the other. |
| ElementSyncBehavior | The synchronization behavior extension. |
| ElementTargetAttributes | This interface define the set of animation target extensions. |
| ElementTest | Defines the test attributes interface. |
| ElementTime | This interface defines the set of timing attributes that are common to all timed elements. |
| ElementTimeContainer | This is a placeholder - subject to change. |
| ElementTimeControl | |
| ElementTimeManipulation | This interface support use-cases commonly associated with animation. |
| SMILAnimateColorElement | This interface represents the SMIL animateColor element. |
| SMILAnimateElement | This interface represents the SMIL animate element. |
| SMILAnimateMotionElement | This interface present the animationMotion element in SMIL. |
| SMILAnimation | This interface define the set of animation extensions for SMIL. |
| SMILDocument | A SMIL document is the root of the SMIL Hierarchy and holds the entire content. |
| SMILElement | The SMILElement interface is the base for all SMIL element
types. |
| SMILLayoutElement | Declares layout type for the document. |
| SMILMediaElement | Declares media content. |
| SMILParElement | |
| SMILRefElement | // audio, video, ... |
| SMILRegionElement | Controls the position, size and scaling of media object elements. |
| SMILRegionInterface | Declares rendering surface for an element. |
| SMILRegionMediaElement | |
| SMILRootLayoutElement | Declares layout properties for the root-layout element. |
| SMILSetElement | This interface represents the set element. |
| SMILSwitchElement | Defines a block of content control. |
| SMILTopLayoutElement | Declares layout properties for the top-layout element. |
| Time | The Time interface is a datatype that represents times within
the timegraph. |
| TimeEvent | The TimeEvent interface provides specific contextual
information associated with Time events. |
| TimeList | The TimeList interface provides the abstraction of an ordered
collection of times, without defining or constraining how this collection
is implemented. |