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IDDrawExclModeVideoCallback Interface

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Microsoft DirectShow 9.0

IDDrawExclModeVideoCallback Interface

The IDDrawExclModeVideoCallback interface is a callback interface for the IDDrawExclModeVideo interface.

This callback 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 the interface. It is important that none of the methods block or slow down the video processing, because this will cause problems with playback.

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.

Method Description
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.

Requirements

Header: Declared in Strmif.h; include Dshow.h.

Library: Use Strmiids.lib.