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CBaseControlWindow.NotifyOwnerMessage method

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[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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.]

The NotifyOwnerMessage method passes along specific messages to the video window.

Syntax

HRESULT NotifyOwnerMessage(
   long     hwnd,
   long     uMsg,
   LONG_PTR wParam,
   LONG_PTR lParam
);

Parameters

hwnd

Handle to the video window.

uMsg

Message details.

wParam

First message parameter.

lParam

Second message parameter.

Return value

Returns NO_ERROR.

Remarks

When the video window is a child of another window, it does not receive certain top-level window messages. These messages can be valuable to a renderer, because they could affect its behavior. NotifyOwnerMessage passes any of the following messages to the video window.

  • WM_ACTIVATEAPP
  • WM_DEVMODECHANGE
  • WM_DISPLAYCHANGE
  • WM_PALETTECHANGED
  • WM_PALETTEISCHANGING
  • WM_QUERYNEWPALETTE
  • WM_SYSCOLORCHANGE

You can request that the IVideoWindow plug-in distributor (PID) make a window become a child of another window. When this occurs, the PID will look for certain messages that might be sent to the owning window. The PID will then forward those messages to the owned window. The default processing for the messages is to send them to the owned window procedure synchronously by calling the Win32 SendMessage function.

Requirements

Requirement Value
Header
Ctlutil.h (include Streams.h)
Library
Strmbase.lib (retail builds);
Strmbasd.lib (debug builds)

See also

CBaseControlWindow Class