CBaseMediaFilter class

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 CBaseMediaFilter class implements the IMediaFilter interface. Use this class for plug-in distributors or other objects that need to support IMediaFilter without supporting the IBaseFilter interface. Do not use this class for filters. Instead, use the CBaseFilter class, or a base class derived from CBaseFilter.

Protected Member Variables	Description
m_State	Current state of the object.
m_pClock	Pointer to the object's reference clock.
m_tStart	Reference time that corresponds to stream time 0.
m_clsid	Class identifier (CLSID) of the object.
m_pLock	Pointer to a critical section.
Public Methods	Description
CBaseMediaFilter	Constructor method.
~ CBaseMediaFilter	Destructor method. Virtual.
StreamTime	Retrieves the current stream time. Virtual.
IsActive	Determines whether the object is active (running or paused).
IPersist Methods	Description
GetClassID	Retrieves the class identifier.
IMediaFilter Methods	Description
GetState	Retrieves the object's state (running, stopped, or paused).
SetSyncSource	Sets a reference clock for the object.
GetSyncSource	Retrieves the reference clock that the object is using.
Stop	Stops the object.
Pause	Pauses the object.
Run	Runs the object.

Requirements

Requirement	Value
Header	Amfilter.h (include Streams.h)
Library	Strmbase.lib (retail builds); Strmbasd.lib (debug builds)