IAMTimelineComp Interface
| Microsoft DirectShow 9.0 |
IAMTimelineComp Interface
The IAMTimelineComp interface inserts or retrieves virtual tracks on a composition in DirectShow Editing Services (DES).
A composition is a collection of layers that acts as a single, composited track . For example, a composition that contains two tracks with a transition between them acts as a single track with the transition precomposited. A composition should contain media of only one type (such as audio or video), but this limitation is not enforced. A virtual track is any object that can reside in a composition, including tracks and other compositions.
The topmost nodes in the timeline are groups. Groups implement both the IAMTimelineComp interface and the IAMTimelineGroup interface.
To create a composition object, call IAMTimeline::CreateEmptyNode with the value TIMELINE_MAJOR_TYPE_COMPOSITE. You can query the returned IAMTimelineObj pointer for the IAMTimelineComp interface. For more information, see The Timeline Model and Constructing a Timeline.
In addition to the methods inherited from IUnknown, the IAMTimelineComp interface exposes the following methods.
| Method | Description |
| GetCountOfType | Retrieves the number of objects of a given type contained in this composition and all of its virtual tracks, recursively. |
| GetNextVTrack | Retrieves the next virtual track after a specified virtual track. |
| GetRecursiveLayerOfType | Performs a depth-first ordering of the virtual tracks contained in this composition, and retrieves the nth virtual track from that ordering. |
| GetRecursiveLayerOfTypeI | Not supported. |
| GetVTrack | Retrieves the virtual track at the specified priority. |
| VTrackGetCount | Retrieves the number of virtual tracks contained in the composition. |
| VTrackInsBefore | Inserts a virtual track into the composition at the specified priority. |
| VTrackSwapPriorities | Switches the priority levels of two tracks. |
Requirements
Header: Include Qedit.h. This header file is not compatible with Microsoft® Direct3D® headers later than version 7.
Library: Use strmiids.lib.