IMediaControl::StopWhenReady method (control.h)

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 StopWhenReady method pauses the filter graph, allowing filters to queue data, and then stops the filter graph.

Syntax

HRESULT StopWhenReady();

Return value

Returns an HRESULT value. Possible values include the following.

Remarks

This method is useful if you want to seek the filter graph while the graph is stopped. As long as the filter graph is stopped, changes in the current position do not repaint the video window with a new frame. Therefore, calling IMediaSeeking::SetPositions does not update the video window. To update the window after the seek operation, call StopWhenReady. This method transitions the graph to a paused state, waits for the pause operation to complete, and then transitions the graph back to stopped. The pause operation queues data in the graph, so that the video renderer receives and displays the new frame.

This method is asynchronous. It waits on a separate thread for the pause to complete. The calling thread does not block, which enables the application to respond to user input. When the method returns, the logical state of the graph is stopped, even before the pause operation completes. If you call the IMediaControl::GetState method at this point, it returns State_Stopped.

If the application issues another state-change command (such as pause, run, or seek) before the pause operation completes, the new command cancels the pending stop command. The pause operation completes, but the graph does not stop.

Requirements

See also

Error and Success Codes

IMediaControl Interface