GmfBridge 不将接收器筛选器与源筛选器连接

GmfBridge doesn't connect sink filter with source filter

本文关键字：筛选 连接 接收器 GmfBridge      更新时间：2023-10-16

我正在尝试使用GmfBridge库动态更改源过滤器从cam到文件，反之亦然。所有函数返回S_OK(好吧，几乎所有- pMediaControlOutput->Run()返回S_FALSE实际上，但在msdn说，这也可以)，所以我假设一切都好，但数据没有传输到桥的另一边。我使用GraphStudio连接到远程图形，一切似乎都没问题-两个图形中的所有过滤器都应该连接。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

因此，正如您所看到的，尽管BridgeGraphs()返回S_OK，但左图没有连接到右图，并且媒体样本被丢弃。下面是我的代码。我哪里做错了?

// 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 ) );

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gmbridge的巨大漏洞。我在这里给出了错误的接口(有图表而不是桥的接收器和源过滤器)coz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正确处理-没有"else"早午餐来处理错误和函数返回hr，这是在begin中设置的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;
}

所以你可以看到，它只是说没有错，然后什么也不做!我认为通知库的作者这个bug是个好主意。

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