Event Notification Codes

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

DirectShow supports system-defined events, which filters in the filter graph pass to the Filter Graph Manager.

Filters pass these events to the Filter Graph Manager by using the IMediaEventSink::Notify method, and the application retrieves them with the IMediaEvent::GetEvent method.

When you retrieve an event by calling GetEvent, the event can contain interface pointers or pointers to allocated memory. Code that uses GetEvent should, therefore, call IMediaEvent::FreeEventParams to free any resources associated with the event's parameters after it handles the event.

The system-defined event notification codes are listed in the Evcode.h header file.

The parameters listed with an event notification code are the ones passed with the code in the CBaseFilter::NotifyEvent function. For example, consider the following statements.

NotifyEvent(EC_OLE_EVENT, (DWORD) bstr, NULL);
NotifyEvent(EC_COMPLETE, S_OK, 0);
NotifyEvent(EC_ERRORABORT, E_FAIL, 0);

Event notification code	Description
EC_ACTIVATE	An audio or video renderer is losing or gaining activation.
EC_BUFFER_FULL	Indicates that the capture buffer is full.
EC_BUFFERING_DATA	The buffering status is changing.
EC_CAP_FILE_COMPLETED	This notification indicates that still image capture has completed.
EC_CAP_FILE_WRITE_ERROR	Indicates that an error occurred while writing captured data to a file.
EC_CAP_SAMPLE_PROCESSED	Indicates that a frame of data has been captured.
EC_CLOCK_CHANGED	The filter graph has changed from one reference clock to another.
EC_COMPLETE	All data has been rendered.
EC_DRM_LEVEL	Notifies when content protected by digital rights management (DRM) requests some form of analog content protection.
EC_END_OF_SEGMENT	Notifies that a segment end has been reached.
EC_ERROR_STILLPLAYING	At least one call to Run failed in an active filter graph. The current state of any underlying filter graph or graphs is indeterminate; they might be running, but some are almost certainly not.
EC_ERRORABORT	An error forced the termination of a requested operation.
EC_FULLSCREEN_LOST	The video renderer is switching out of full-screen mode.
EC_NEED_RESTART	The current graph must be stopped and restarted.
EC_NOTIFY_WINDOW	Pass the window handle around during pin connection.
EC_OLE_EVENT	A filter is passing a text string to the application.
EC_OPENING_FILE	The open file status is changing.
EC_PLAY_NEXT	The user has initiated an asynchronous request to play back the next track.
EC_PLAY_PREVIOUS	The user has initiated an asynchronous request to play back the previous track.
EC_PALETTE_CHANGED	The video palette has changed.
EC_QUALITY_CHANGE	The playback quality has changed.
EC_REPAINT	A repaint is required.
EC_SEGMENT_STARTED	Notifies that a new segment has been started.
EC_SHUTTING_DOWN	The filter graph is starting to shut down. DirectShow passes this notification to any plug-in distributors that support the IMediaEventSink interface.
EC_STARVATION	One of the filters (usually a parser or file source filter) is not receiving enough data. By default, the filter graph manager will pause all running filters and then return to normal operation when enough data is available.
EC_STREAM_CONTROL_STARTED	The starting reference time from an earlier call to IAMStreamControl::StartAt passed.
EC_STREAM_CONTROL_STOPPED	The stopping reference time from an earlier call to IAMStreamControl::StopAt passed.
EC_STREAM_ERROR_STILLPLAYING	The stream is still playing, but should not be playing.
EC_STREAM_ERROR_STOPPED	The stream has stopped, but should not have stopped.
EC_TIME	The requested reference time occurred.
EC_USERABORT	A user has forced the termination of a requested operation.
EC_VIDEO_SIZE_AR_CHANGED	The size or aspect ratio of the native video has changed.
EC_VIDEO_SIZE_CHANGED	The size of the native video has changed.
EC_WINDOW_DESTROYED	The video renderer's filter is being removed or destroyed.

See Also

Reference

DirectShow Macros