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IStreamBuilder::Backout

 
Microsoft DirectShow 9.0

IStreamBuilder::Backout

The Backout method undoes steps taken in the IStreamBuilder::Render method. This includes disconnecting and removing any filters that were added inside Render.

Syntax

  HRESULT Backout(
  IPin *ppinOut,
  IGraphBuilder *pGraph
)

Parameters

ppinOut

[in] Pointer to the IPin interface of this pin.

pGraph

[in] Pointer to the IGraphBuilder interface of the Filter Graph Manager.

Return Value

Returns an HRESULT value. A return code of S_OK indicates to the graph builder that the disconnect was successful.

Remarks

The following example shows how a filter would reverse the steps that are shown in the code example for the IStreamBuilder::Render method:

STDMETHODIMP CMyOutputPin::BackOut(IPin *pPin, IGraphBuilder *pGraph)
{
    CheckPointer(pPin, E_POINTER);
    CheckPointer(pGraph, E_POINTER);

    HRESULT hr = S_OK;
    if (m_Connected != NULL) // Pointer to the pin we're connected to.
    {
        // Find the filter that owns the pin connected to us.
        FILTER_INFO fi;
        hr = m_Connected->QueryFilterInfo(&fi);
        if (SUCCEEDED(hr)) 
        {
            if (fi.pFilter != NULL) 
            {
                //  Disconnect the pins.
                pGraph->Disconnect(m_Connected);
                pGraph->Disconnect(pPin);
                // Remove the filter from the graph.
                pGraph->RemoveFilter(fi.pFilter);
                fi.pFilter->Release();
            } 
            else 
            {
                hr = E_UNEXPECTED;
            }
        }
    }
    return hr;
}

Requirements

Header: Declared in Strmif.h; include Dshow.h.

Library: Use Strmiids.lib.

See Also