c++ - GmfBridge 不将接收器过滤器与源过滤器连接

Question

我正在尝试使用 GmfBridge 库将源过滤器从 cam 动态更改为文件，反之亦然。所有函数都返回 S_OK(嗯，几乎所有 - pMediaControlOutput->Run() 实际上返回 S_FALSE，但在 msdn 中说这也可以)，所以我假设一切正常但数据没有传输到另一个桥的一侧。我使用 GraphStudio 连接到远程图形，一切似乎都正常 - 两个图形中的所有过滤器都按应有的方式连接。但是在播放时我在桥日志文件中收到以下消息:

0:  Started 2011-09-10 15:58:38
0:  Buffer minimum 100
0:  Added stream 1: 畡楤o, Decompressed Only, Discard mode
1:  Sink 0x7ae0ca8 has 1 pins
1:  Sink filter 0x7ae0cf8 in graph 0x193bf0
2:  Source 0x7ae1030 has 1 pins
2:  Source filter 0x7ae1080 in graph 0x194c18
14: ReceiveConnection Aware: false
14: Bridging 0x194c18 to 0x193bf0
14: Pin 0x7ae3438 disconnect
25: Source 0x7ae1030 pause from 0
25: Source pin 0x7ae3618 active
2234: Pin 0x7ae3438 receive 0x721ec68
2234: Sink pin 0x7ae3438 disconnected: discarding 0x721ec68
3389: Pin 0x7ae3438 receive 0x721ec68
3389: Sink pin 0x7ae3438 disconnected: discarding 0x721ec68
3940: Pin 0x7ae3438 receive 0x721ec68
3940: Sink pin 0x7ae3438 disconnected: discarding 0x721ec68
4440: Pin 0x7ae3438 receive 0x721ec68

如您所见，尽管 BridgeGraphs() 返回 S_OK 并且媒体样本被丢弃，但左图并未连接到右图。下面是我的代码。我哪里错了？

// Create graphs
HRESULT hr = m_graphInput.CreateInstance(CLSID_FilterGraph);
ATLASSERT( SUCCEEDED( hr ) );
hr = m_graphOutput.CreateInstance(CLSID_FilterGraph);
ATLASSERT( SUCCEEDED( hr ) );

// Get IMediaControl interfaces
hr = m_graphInput.QueryInterface( IID_IMediaControl, (void**)&pMediaControlInput );
ATLASSERT( SUCCEEDED( hr ) );
hr = m_graphOutput.QueryInterface( IID_IMediaControl, (void**)&pMediaControlOutput );
ATLASSERT( SUCCEEDED( hr ) );

// Get builder interfaces
hr = m_graphInput.QueryInterface( IID_IGraphBuilder, (void**)&pBuilderInput );
ATLASSERT( SUCCEEDED( hr ) );
hr = m_graphOutput.QueryInterface( IID_IGraphBuilder, (void**)&pBuilderOutput );
ATLASSERT( SUCCEEDED( hr ) );

// Load source filter (on sink side)
LocateFilter( SOURCE_FILTER_NAME, CLSID_LegacyAmFilterCategory, &inputDevice );
hr = m_graphInput->AddFilter( inputDevice, SOURCE_FILTER_NAME );
ATLASSERT( SUCCEEDED( hr ) );

// Load render filter (on bridge's source side)
LocateFilter( _T( "Default DirectSound Device" ), CLSID_AudioRendererCategory, &audioOutputPreview );
hr = m_graphOutput->AddFilter( audioOutputPreview,  _T( "Default DirectSound Device" ) );
ATLASSERT( SUCCEEDED( hr ) );

// Init bridge
bridge.CreateInstance( __uuidof(GMFBridgeController) );
hr = bridge->SetBufferMinimum( 100 );
ATLASSERT( SUCCEEDED( hr ) );
hr = bridge->AddStream( false, eUncompressed, false );
ATLASSERT( SUCCEEDED( hr ) );

// Add sink filter and connect to input graph
IUnknownPtr pSinkFilter;
{
   hr = bridge->InsertSinkFilter( m_graphInput, (IUnknown**)&pSinkFilter );
   ATLASSERT( SUCCEEDED( hr ) );

   // Using own functions get pins
   IPin* pInAudio = CPinController::getOutputPin( inputDevice, _T("Audio"));
   IPin* pOutAudio = CPinController::getInputPin( pSinkFilter );
   hr = pBuilderInput->Connect( pOutAudio, pInAudio );
   ATLASSERT( SUCCEEDED( hr ) );
}

// Add output filter and connect to output graph 
IUnknownPtr pFeederFilter;
{
   hr = bridge->InsertSourceFilter( pSinkFilter, m_graphOutput, &pFeederFilter );
   ATLASSERT( SUCCEEDED( hr ) );

   // Get pins
   IPin* pInAudio = CPinController::getOutputPin( pFeederFilter/*, _T("Audio")*/);
   IPin* pOutAudio = CPinController::getInputPin( audioOutputPreview );
   hr = pBuilderOutput->Connect( pInAudio, pOutAudio );
   ATLASSERT( SUCCEEDED( hr ) );
}

// Run left
hr = pMediaControlInput->Run();
ATLASSERT( SUCCEEDED( hr ) );

// Run right
hr = pMediaControlOutput->Run();
ATLASSERT( SUCCEEDED( hr ) );

hr = bridge->BridgeGraphs( m_graphOutput, m_graphInput );
ATLASSERT( SUCCEEDED( hr ) );

Answer 1

这真的很荒谬，但大约几分钟前，经过一天的搜索，我们找到了答案。所有的交易都是关于 GmfBridge 中的巨大漏洞。我在这里给出了错误的接口(interface)(有图形而不是桥的接收器和源过滤器)'因为函数需要指向 IUnknown 的指针:

hr = bridge->BridgeGraphs( m_graphOutput, m_graphInput );

在 GmfBridge 库中，这种情况没有得到妥善处理——没有“else”brunch 来处理错误，函数返回在 begin 中设置的 hr 到 S_OK:

HRESULT STDMETHODCALLTYPE BridgeGraphs( 
        /* [in] */ IUnknown *pSourceGraphSinkFilter,
        /* [in] */ IUnknown *pRenderGraphSourceFilter)
{
    HRESULT hr = S_OK;
    ...
    // if we are not given both filters, then 
    // we need do nothing
    IBridgeSinkPtr pSink = pSourceGraphSinkFilter;
    IBridgeSourcePtr pSource = pRenderGraphSourceFilter;
    if ((pSink != NULL) && (pSource != NULL))
    {
        ...
    }

    return hr;
}

如您所见，它只是说没有问题，然后什么也不做!我认为将此错误通知库的作者是个好主意。希望此信息对某人有所帮助。