This method sets the default source of synchronization.

HRESULT SetDefaultSyncSource(void);



Return Values

Returns an HRESULT value that depends on the implementation. HRESULT can be one of the following standard constants, or other values not listed.

Value Description
E_FAIL Failure.
E_POINTER Null pointer argument.
E_INVALIDARG Invalid argument.
E_NOTIMPL Method is not supported.
S_OK or NOERROR Success.


This method is used when no clock has been given to the filter graph, and the filter graph manager consequently must find a clock to use as the synchronization source. The filter graph manager first tries all filters, starting with renderers, to see if any filter exports a clock (by providing an IReferenceClock interface). The filter graph manager will choose the first filter that it finds, providing that filter is connected to an upstream source. If no connected filters are found, the first filter if IReferenceClock is used. Typically, this will be the audio rendering filter. If no filter exports a clock, the filter graph manager uses a system clock.


DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.

OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.

See Also

IFilterGraph Interface

Last updated on Wednesday, April 13, 2005

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