Inactive method notifies the pin that the filter is no longer active.
virtual HRESULT Inactive();
This method has no parameters.
When the filter stops, the CBaseFilter class calls this method on all of the filter's connected pins.
This method does nothing in the base class. Derived classes should override this method to free any resources obtained by the CBasePin::Active method; for example, to decommit the pin's allocators.
The filter graph manager's internal state is not updated until after this method returns, so do not test the state from this method.