IWMReaderCallback interface (wmsdkidl.h)

[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 It has been superseded by Source Reader and Sink Writer.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.]

The IWMReaderCallback is implemented by the application to handle data being read from a file. A pointer to the interface is passed to IWMReader::Open.


The IWMReaderCallback interface inherits from IWMStatusCallback. IWMReaderCallback also has these types of members:


The IWMReaderCallback interface has these methods.


The OnSample method is called during the reading of a file (due to a Start call) indicating that new data is available.


Target Platform Windows
Header wmsdkidl.h

See also

IWMReader Interface

IWMReaderAdvanced Interface

IWMReaderCallbackAdvanced Interface



Reader Object

Reading ASF Files