Using the Callback Methods

[The feature associated with this page, Windows Media Format 11 SDK, is a legacy feature. It has been superseded by Source Reader and Sink Writer. Source Reader and Sink Writer have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Source Reader and Sink Writer instead of Windows Media Format 11 SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

Several interfaces in the Windows Media Format SDK contain methods that are called asynchronously. Most of these methods use callback functions to pass information to the controlling application.

The following sections describe some of the general issues regarding the use of callback methods with the Windows Media Format SDK.

Section	Description
Using the OnStatus Callback	Describes how to implement the IWMStatusCallback::OnStatus callback method, which is used by several objects to advise applications of SDK operation progress.
Using Events with Asynchronous Calls	Describes a common technique to handle asynchronous method calls in an application.
Using the Context Parameter	Introduces the pvContext parameter, shared by several callbacks and their calling methods, and explains how to use it.

 

Related topics

Programming Guide