IBaseFilter::JoinFilterGraph method (strmif.h)

Article
02/22/2024

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 JoinFilterGraph method notifies the filter that it has joined or left the filter graph.

Syntax

HRESULT JoinFilterGraph(
  [in] IFilterGraph *pGraph,
  [in] LPCWSTR      pName
);

Parameters

[in] pGraph

Pointer to the Filter Graph Manager's IFilterGraph interface, or NULL if the filter is leaving the graph.

[in] pName

Pointer to a wide-character string that specifies a name for the filter.

Return value

Returns S_OK if successful, or an HRESULT value indicating the cause of the error.

Remarks

When the Filter Graph Manager adds a filter to the filter graph, it calls this method with a pointer to itself. It assigns a name for this instance of the filter through the pName parameter. The name can be retrieved by calling the IBaseFilter::QueryFilterInfo method.

When the Filter Graph Manager removes the filter from the graph, it calls this method with a NULL pointer.

Applications should never call this method. To add a filter to the graph, call the IFilterGraph::AddFilter method on the filter graph manager.

Filter developers: The filter can store the IFilterGraph interface pointer and query it for other Filter Graph Manager interfaces. However, it must never hold a reference count on the Filter Graph Manager. Doing so creates a circular reference count, because the Filter Graph Manager keeps a reference count on the filter. A circular reference count prevents the interface from being released properly, which can lead to a deadlock. The IFilterGraph interface is guaranteed to be valid until the Filter Graph Manager calls this method again with the value NULL. For an implementation of this method, see the CBaseFilter::JoinFilterGraph method.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	strmif.h (include Dshow.h)
Library	Strmiids.lib