在c中編組自定義directshow過濾器界面＃

嘿夥計們，我一直在這個過去幾天卡住了。我有一個自定義COM接口，我可以投到，但是當我調用一個，如果它的功能，我得到一個AccessViolationException，因爲這個指針已經改變。在c中編組自定義directshow過濾器界面＃

下面的代碼表示我編組的兩個接口。所有的方法都會導致同樣的問題。

任何幫助將不勝感激。

/* 
    struct SourceConfig {  
     LONGLONG       llBufferDuration;   // The buffer duration to use while receiving samples from the network, measured in 100nsec units 
     REFERENCE_TIME      rtStartTime; 
     FLOAT        fRate;      // Negative: rewind, Positive: forward 
     BYTE        btConnectionTimeout;  // The time to wait for a connection to be established, measured in seconds 
     BOOL        bKeyFramesOnly; 
     CHAR        pIP[128]; 
     WORD        wPort; 
     CHAR        pChannel[64]; 
     BYTE        pbtCertificate[96]; 
     SAMPLE_TIME       eSampleTime;// Indicates weather to directly route the samples with the absolute UTC 
                 // time OR to make all generated samples relative to zero, default value 
                 // is 'RELATIVE'. 
     HANDLE        hEvent;      // Used to wait for the operation completion (optional) 
     BYTE        bAutoSeekToNextAvailPos; // If seeking into a hole automatically resume streaming from the next available position 
     DWORD        dwSampleStarvationTimeout; // The maximal amount of seconds (and not msec) the filter might wait for incoming data 
    }; 


    interface 
    __declspec(uuid("{9331DC40-40F5-438a-B9C0-44B479246C98}")) 
    IStreamingSourceCallback : IUnknown { 
     virtual STDMETHODIMP OnStreamingSourceEvent(IN STREAMING_SRC_EVENT eCode, IN const VARIANT* pvar1 = 0, IN const VARIANT* pvar2 = 0, IN const VARIANT* pvar3 = 0) = 0; 
    }; 

    interface 
    __declspec(uuid("{ECF7715E-E973-4bb9-AEED-389845F0E297}")) 
    IStreamingSource : IUnknown { 
     virtual HRESULT GetConfig(OUT SourceConfig* pCfg) = 0; 
     virtual HRESULT SetConfig(IN const SourceConfig* pCfg) = 0; 
     virtual HRESULT SetCallback(IN IStreamingSourceCallback* pCallback) = 0; 
     virtual HRESULT UpdateAbsoluteRefTime(IN LONGLONG& llRefTime) = 0; 

     virtual HRESULT GetSeekPos(IN OUT REFERENCE_TIME& rtSeek) = 0; 
    }; 

*/ 

public enum SAMPLE_TIME : byte 
{ 
    Relative, 
    Absolute 
}; 

[StructLayout(LayoutKind.Sequential)] 
public struct SourceConfig 
{ 
    long BufferDuration; 
    long StartTime; 
    float Rate; 
    byte ConnectionTimeout; 
    [MarshalAs(UnmanagedType.Bool)] 
    bool KeyFramesOnly; 
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)] 
    public string Ip; 
    UInt16 Port; 
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 64)] 
    public string Channel; 
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 96)] 
    public byte[] Certificate; 
    SAMPLE_TIME SampleTime; 
    IntPtr Event; 
    byte AutoSeekToNextAvailPos; 
    uint SampleStarvationTimeout; 
}; 

public enum STREAMING_SRC_EVENT : int 
{ 
    SRC_NONE, 
    SRC_CONNECTED, 
    SRC_DISCONNECTED, 
    SRC_ERROR, 
    SRC_STARTTIME, 
    SRC_STREAM_CLOSE2LIVE, 
    SRC_STREAM_FAR_LIVE, 
    SRC_NEARESTSEEK 
}; 

[ComImport, Guid("9331DC40-40F5-438a-B9C0-44B479246C98"), SuppressUnmanagedCodeSecurity, InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] 
public interface IStreamingSourceCallback 
{ 
    [PreserveSig] 
    int OnStreamingSourceEvent(
     [In, MarshalAs(UnmanagedType.I4)] STREAMING_SRC_EVENT code, 
     [In, MarshalAs(UnmanagedType.IUnknown)] object var1, 
     [In, MarshalAs(UnmanagedType.IUnknown)] object var2, 
     [In, MarshalAs(UnmanagedType.IUnknown)] object var3); 
} 

[ComImport, Guid("ECF7715E-E973-4bb9-AEED-389845F0E297"), SuppressUnmanagedCodeSecurity, InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] 
public interface IStreamingSource 
{ 
    [PreserveSig] 
    int GetConfig([Out, MarshalAs(UnmanagedType.Struct)] out SourceConfig config); 
    [PreserveSig] 
    int SetConfig([In, MarshalAs(UnmanagedType.Struct)] SourceConfig config); 
    [PreserveSig] 
    int SetCallback([In, MarshalAs(UnmanagedType.Interface)] IStreamingSourceCallback callback); 
    [PreserveSig] 
    int UpdateAbsoluteRefTime([In, MarshalAs(UnmanagedType.I8)] ref long refTime); 
    [PreserveSig] 
    int GetSeekPos([In, Out, MarshalAs(UnmanagedType.I8)] ref long seekTime); 
}

下面的代碼演示用法：

IStreamingSource ssInterface = vosFilter as IStreamingSource; 
     if (ssInterface == null) 
     { 
      throw new ApplicationException("Could not get IStreamingSource. "); 
     } 

     if ((hr = ssInterface.SetCallback(_ssCallback)) < 0) 
     { 
      throw new ApplicationException("Could not set streaming source callback. " + DirectShowLib.DsError.GetErrorText(hr)); 
     }

ssInterface點，正確的架構，只要通過對SetCallback加強，這點到垃圾。

謝謝。

來源

2010-01-21 Itamar

如果您在SetCallback方法sig的IStreamingSourceCallback參數中取出MarshalAs（UnmanagedType.Interface），還會得到錯誤嗎？

來源

2010-01-23 03:23:47

在c中編組自定義directshow過濾器界面＃

回答

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