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DirectShow QASF Reference

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 It has been superseded by Source Reader and Sink Writer.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

This section contains programming references for the following DirectShow QASF filters, interfaces and enumerations. The DirectShow SDK documentation contains reference and programming guide materials for additional generic interfaces exposed by these filters, such as IBaseFilter and IPin, and for earlier versions of the QASF components.

For an explanation of the QASF name, see About DirectShow.

The following filters are included with the DirectShow QASF components.

Filter Description
WM ASF Reader Filter Reads and parses local or remote ASF files.
WM ASF Writer Filter Creates ASF files from compressed or uncompressed input streams.

 

The following interfaces are defined for use with the DirectShow QASF components.

Interface Description
IAMWMBufferPass Provides a method that enables applications to register for callbacks from the input pins of the WM ASF Writer or the output pins of the WM ASF Reader filter. Used in indexing and when adding data unit extensions.
IAMWMBufferPassCallback Implemented by applications and called by the filters. Applications use the one method on this interface to obtain information about individual samples in the stream. Used in indexing and when adding data unit extensions.
IConfigAsfWriter Implemented on the WM ASF Writer. Used by applications to specify profiles and indexing parameters for the file.
IConfigAsfWriter2 Provides additional configuration functions on the WM ASF Writer.

 

The following enumeration, structure, and events are defined for use with the DirectShow QASF components.

Enumeration Description
_AM_ASFWRITERCONFIG_PARAM Defines filter configuration parameters used in the IConfigAsfWriter2::GetParam and SetParam methods.

 

Structure Description
AM_WMT_EVENT_DATA Contains information pertaining to a WMT_STATUS event and the associated status code returned by the Windows Media Format SDK.

 

Event Description
EC_WMT_EVENT Event forwarded from the Windows Media Format SDK.
EC_WMT_INDEX_EVENT Sent when an application uses the WM ASF Writer to index Windows Media Video files.