掌握 dump filter 的用法：采集MPG,AVI和ASF的程序代码

 

http://www.360doc.com/content/08/0705/23/29694_1401883.shtml 此网址有源码

 

下面的程序代码示范了如何用VW卡采集MPG,AVI或ASF文件。 本程序是基于DirectShow通过VW卡的DirectShow Source Filter及相关Filter实现文件采集。 由于在这里AVI,ASF格式文件均为MPEG-4视频，所以，为简单起见，MPG文件也为MPEG-4视频，即前面文章所提高的MPEG-4 Embedded MPEG-2。

在程序运行后，首先创建一个Filter Graph,其中仅含有VW Source Filter并进行相应的设置，在本实例中设置的参数为： PAL复合视频输入，MPEG-4 Program编码，视频位速率为1M bps, 分辨率为720 x 576 , 音频位速率192K bps, 44.1K采样频率，MPEG-1 L2 音频编码(AVI文件的音频编码为PCM)。然后，根据选择不同的输出文件 格式，完成相应的Filte Graph。

1. 创建基本的Filter Graph

// We create a Filter graph including Source Filter only.
// For every usage, we add other usaful filter into the graph
// and remove useless filters.
HRESULT CCap4Dlg::CraeteBaseCaptureGraph ()
{
	HRESULT hr;
	IBaseFilter *pSrc = NULL;

    if (m_pGraph)
    {
        SAFE_RELEASE (m_pGraph);
    }

	__try {
		// 创建Filter Graph
		CHECK_HR( hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC,	/
					IID_IGraphBuilder, (void **)&m_pGraph));
		// 创建Source Filter实例并加入到Filter Graph中.
		CHECK_HR( hr = CoCreateInstance(CLSID_VWSource, NULL,CLSCTX_INPROC,IID_IBaseFilter,(void**)&pSrc));
		CHECK_HR( hr = m_pGraph->AddFilter(pSrc, L"Source Filter"));

		ISrcControl * p_ISrc;

		CHECK_HR( hr = pSrc->QueryInterface (IID_ISrcControl, (void **)&p_ISrc));	// 获取接口指针
		p_ISrc->SetAudioEncodeFormat (1);		// MPEG-1 L2
		p_ISrc->SetDeviceNumber (0);		// 指定操作0号卡
		p_ISrc->SetStreamType (3);		// 指定MPEG-4 Program
		p_ISrc->SetVideoSource (VW_COMPOSITE);		// 复合输入
		p_ISrc->SetVideoStandard (VW_SRC_PAL);		// PAL
		p_ISrc->SetVideoResolution (VW_VIDEO_RESOLUTION_FULL_720);	// 720 x 576
		p_ISrc->SetVideoBitrate (1000000);			// 1M bps视频位速率
		p_ISrc->SetAudioFrequency(VW_AUDIO_FREQ_44100);	// 44.1KHz音频采样
		p_ISrc->SetAudioBitrate(VW_AUDIO_BITRATE_192);	// 192K 音频位速率
		p_ISrc->SetParameterActive ();
		SAFE_RELEASE (p_ISrc);

	}__finally {
		SAFE_RELEASE(pSrc);

        if (FAILED(hr)){
			SAFE_RELEASE(m_pGraph);
		}
	}
#ifdef _DEBUG
	if (SUCCEEDED(hr)) 
		AddGraphToRot(m_pGraph, &m_dwGraphRegister);
#endif
	return hr;
}

2. 创建MPG文件采集的Filter Graph
创建用于采集MPG文件的Filter Graph 比较简单，只需要加入Dump Filter,把它连接到Source Filter就行了。
// Remove all filters except source filter, then add Dump filter

HRESULT CCap4Dlg::UpdateCaptureGraphForMpg (const char * filename)
{
	HRESULT hr = E_FAIL;
	IBaseFilter * pSrc = NULL;
	IBaseFilter * pDump = NULL;
	IFileSinkFilter *pSink = NULL;
	WCHAR wFile[512];
	IPin * pSrcPin;
	IPin * pDstPin;

#ifdef _DEBUG
	if (m_dwGraphRegister) {
		RemoveGraphFromRot(m_dwGraphRegister);
		m_dwGraphRegister = 0;
	}
#endif
	__try {
		CHECK_HR (hr = m_pGraph->FindFilterByName (L"Source Filter", &pSrc));
		TearDownGraph (pSrc);

		// Create and add Dump Filter
		CHECK_HR( hr = CoCreateInstance(CLSID_Dump,NULL,CLSCTX_INPROC,IID_IBaseFilter,(void**)&pDump));
		CHECK_HR( hr = m_pGraph->AddFilter(pDump, L"Dump"));

		CHECK_HR( hr = pDump->QueryInterface (IID_IFileSinkFilter, (void **)&pSink));
		MultiByteToWideChar(CP_ACP, 0, filename, -1, wFile, NUMELMS(wFile));
		pSink->SetFileName (wFile, NULL);

		// Connect Source to Dump
		pSrcPin = GetOutPin (pSrc, 0);
		pDstPin = GetInPin (pDump, 0);
		CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));
	}__finally {
		SAFE_RELEASE(pSink);
		SAFE_RELEASE(pDump);
		SAFE_RELEASE(pSrc);
	}

#ifdef _DEBUG
	if (SUCCEEDED(hr)) 
		AddGraphToRot(m_pGraph, &m_dwGraphRegister);
#endif
	return hr;
}

用于采集mpg文件的Filter Graph如下图

 

3. 创建AVI文件采集的Filter Graph

 

创建AVI文件采集的Filter Graph要稍微复杂一些，我们直接利用VW Source Video的Video和Audio输出Pin,把他们连接到AVI Mux filter,由于是采用PCM音频编码，我们要连接一个MPEG Audio Decoder Filter在VW Source Filter Pin2到AVI Mux。VW Source Filter的Pin0,即输出MPEG Multiplexing Stream 的Pin上实现的主线程，我们不能让他空在这儿，所以就用一个NullRenderer Filter连接到这个Pin上。最后把AVI Mux连接到File Witer filter。

// Remove all filters except source filter, then add AVI Mux filter
HRESULT CCap4Dlg::UpdateCaptureGraphForAvi (const char * filename)
{
	HRESULT hr = E_FAIL;
	IBaseFilter * pSrc = NULL;
	IBaseFilter * pFileWriter = NULL;
	IBaseFilter * pMux = NULL;
	IBaseFilter * pAudDec = NULL;
	IBaseFilter * pNullRnd = NULL;
	IFileSinkFilter *pSink = NULL;
	WCHAR wFile[512];
	IPin * pSrcPin;
	IPin * pDstPin;

#ifdef _DEBUG
	if (m_dwGraphRegister) {
		RemoveGraphFromRot(m_dwGraphRegister);
		m_dwGraphRegister = 0;
	}
#endif
	__try {
	CHECK_HR (hr = m_pGraph->FindFilterByName (L"Source Filter", &pSrc));
	TearDownGraph (pSrc);

	CHECK_HR( hr = CoCreateInstance(CLSID_NullRenderer, NULL,CLSCTX_INPROC,IID_IBaseFilter,(void**)&pNullRnd));
	CHECK_HR( hr = m_pGraph->AddFilter(pNullRnd, L"Null Render"));
	pSrcPin = GetOutPin (pSrc, 0);
	pDstPin = GetInPin (pNullRnd, 0);
	CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));

	CHECK_HR( hr = CoCreateInstance(CLSID_AviDest, NULL,CLSCTX_INPROC,IID_IBaseFilter,(void**)&pMux));
	CHECK_HR( hr = m_pGraph->AddFilter(pMux, L"AVI Mux"));

	CHECK_HR( hr = CoCreateInstance(CLSID_CMpegAudioCodec,NULL,CLSCTX_INPROC,IID_IBaseFilter,(void**)&pAudDec));	
	CHECK_HR( hr = m_pGraph->AddFilter(pAudDec, L"Audio Decoder"));

	CHECK_HR( hr = CoCreateInstance(CLSID_FileWriter, NULL,CLSCTX_INPROC,IID_IBaseFilter,(void**)&pFileWriter));
	CHECK_HR( hr = m_pGraph->AddFilter(pFileWriter, L"File Writer"));

	CHECK_HR( hr = pFileWriter->QueryInterface (IID_IFileSinkFilter, (void **)&pSink));
	MultiByteToWideChar(CP_ACP, 0,filename, -1, wFile, NUMELMS(wFile));
	pSink->SetFileName (wFile, NULL);

	pSrcPin = GetOutPin (pSrc, 1);
	pDstPin = GetInPin (pMux, 0);
	CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));

	pSrcPin = GetOutPin (pSrc, 2);
	pDstPin = GetInPin (pAudDec, 0);
	CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));

	pSrcPin = GetOutPin (pAudDec, 0);
	pDstPin = GetInPin (pMux, 1);
	CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));

	pSrcPin = GetOutPin (pMux, 0);
	pDstPin = GetInPin (pFileWriter, 0);
	CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));

	}__finally {
		SAFE_RELEASE(pMux);
		SAFE_RELEASE(pNullRnd);
		SAFE_RELEASE(pFileWriter);
		SAFE_RELEASE(pSink);
		SAFE_RELEASE(pAudDec);
		SAFE_RELEASE(pSrc);
	}
#ifdef _DEBUG
	if (SUCCEEDED(hr)) 
		AddGraphToRot(m_pGraph, &m_dwGraphRegister);
#endif
	return hr;
}

创建后的Filter Graph如下图：

 

4. 创建ASF文件采集的Filter Graph.
创建ASF文件采的Filter Graph和前面的AVI文件采集Filter Graph差不多,但ASF Writer中包含了文件存储,所以不需要 File Writer或Dump这样的文件输出Filter了.

// Remove all filters except source filter, then add ASF Mux filter
HRESULT CCap4Dlg::UpdateCaptureGraphForAsf (const char * filename)
{
	HRESULT hr = E_FAIL;
	IBaseFilter * pSrc = NULL;
	IBaseFilter * pMux = NULL;
	IBaseFilter * pNullRnd = NULL;
	IFileSinkFilter *pSink = NULL;
	WCHAR wFile[512];
	IPin * pSrcPin;
	IPin * pDstPin;

#ifdef _DEBUG
	if (m_dwGraphRegister) {
		RemoveGraphFromRot(m_dwGraphRegister);
		m_dwGraphRegister = 0;
	}
#endif
	__try {
		CHECK_HR (hr = m_pGraph->FindFilterByName (L"Source Filter", &pSrc));
		TearDownGraph (pSrc);

		CHECK_HR( hr = CoCreateInstance(CLSID_NullRenderer, NULL,CLSCTX_INPROC,IID_IBaseFilter, (void**)&pNullRnd));
		CHECK_HR( hr = m_pGraph->AddFilter(pNullRnd, L"Null Render"));
		pSrcPin = GetOutPin (pSrc, 0);
		pDstPin = GetInPin (pNullRnd, 0);
		CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));

		CHECK_HR( hr = CoCreateInstance(CLSID_ASFWRITER, NULL,CLSCTX_INPROC,IID_IBaseFilter,(void**)&pMux));
		CHECK_HR( hr = m_pGraph->AddFilter(pMux, L"ASF Mux"));
		CHECK_HR( hr = pMux->QueryInterface (IID_IFileSinkFilter, (void **)&pSink));
		MultiByteToWideChar(CP_ACP, 0,filename, -1, wFile, NUMELMS(wFile));
		pSink->SetFileName (wFile, NULL);

		pSrcPin = GetOutPin (pSrc, 1);
		pDstPin = GetInPin (pMux, 0);
		CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));

		pSrcPin = GetOutPin (pSrc, 2);
		pDstPin = GetInPin (pMux, 1);
		CHECK_HR( hr = m_pGraph->Connect (pSrcPin, pDstPin));
	}__finally {
		SAFE_RELEASE(pMux);
		SAFE_RELEASE(pNullRnd);
		SAFE_RELEASE(pSink);
		SAFE_RELEASE(pSrc);
	}
#ifdef _DEBUG
	if (SUCCEEDED(hr)) 
		AddGraphToRot(m_pGraph, &m_dwGraphRegister);
#endif
	return hr;
}

创建后的Filter Graph如下图: