EC_ACTIVATE

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

A video window is being activated or deactivated.

Parameters

lParam1

(BOOL) TRUE if the window is activated, or FALSE if the window is deactivated.

lParam2

(IUnknown*) Pointer to the renderer's IBaseFilter interface.

Default Action

The filter graph manager sets the focus, through the IResourceManager interface. It does not send the event notification to the application.

Remarks

A video renderer sends this event whenever its window is activated or deactivated (that is, when it receives a WM_ACTIVATEAPP message). Window activation or deactivation can occur because the window has gained or lost focus, or because the renderer has switched between full-screen mode and windowed mode.

This event enables the filter graph manager to allocate resources that depend on window focus, such as audio devices.

Requirements

Requirement Value
Header
Dshow.h

See also

Event Notification Codes

Event Notification in DirectShow