|Microsoft DirectX 9.0|
The IDDrawExclModeVideoCallback interface enables applications to get synchronous notification about changes to the overlay position, size, visibility, and so on, so that the application can adjust its video visibility, size, and position. This avoids any color key flash at the beginning, end, or during playback. The application must implement a COM object supporting this interface.
Implement this interface if you are using an IDDrawExclModeVideo interface and want the callback information. It is important that none of the methods block or slow down the video processing, because this will cause problems with playback. The DDrawXCL sample illustrates how to implement this interface.
Use this interface if you are writing a filter that supports IDDrawExclModeVideo or needs to generate callbacks to enable an application to draw color keys at the right time.
In addition to the methods inherited from IUnknown, the IDDrawExclModeVideoCallback interface exposes the following methods.
|OnUpdateColorKey||Informs the application that the color key has changed so that the application can use the new color key to overlay graphics on the video.|
|OnUpdateOverlay||Informs the application when the overlay surface for the video is about to change.|
|OnUpdateSize||Informs the application when the size of the video rectangle is about to change.|