轉自: http://blog.csdn.net/bwmwm/article/details/5463852

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1.創建一個空的Dll工程，添加5個空文件分別名為：MyOutputPin.h、MySourceFilter.h、MyOutputPin.cpp、MySourceFilter.cpp和MySourceFilter.def。

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2.聲明兩個類，一個是Filter的實現類，一個是輸出Pin的實現類，由于是最簡單的源Filter，因此Filter只有一個輸出Pin。實現的功能是從本地磁盤讀取三個圖片文件，輪流顯示這三張圖片，效果是模擬一個視頻流。這兩個類的聲明代碼：

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[cpp]?view plaincopyprint?

//MySourceFilter.h??

class?CMySourceFilter???

????//從SDK庫中的CSource類派生??

????:???public?CSource????????????

{??

public:??

????//實例化接口??

????static?CUnknown?*?WINAPI?CreateInstance(LPUNKNOWN?lpunk,?HRESULT?*phr);??

private:??

????//構造函數??

????CMySourceFilter(LPUNKNOWN?lpunk,?HRESULT?*phr);???

};??

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//MyOutputPin.h??

class?CMyOutputPin???

????//CSource的派生類都使用CSourceStream的派生類做為pin??

????:public?CSourceStream??

{??

public:??

????CMyOutputPin(HRESULT?*phr,?CSource?*pFilter);??

????~CMyOutputPin(void);??

??

????//填充樣本函數??

????//參數pMediaSample就是要傳遞到下一個Filter輸入pin的樣本??

????//把數據填充到pMediaSample中就是這個函數的功能??

????HRESULT?FillBuffer(IMediaSample?*pMediaSample);??

??

????//協商每個CMediaSample數據塊的大小??

????HRESULT?DecideBufferSize(IMemAllocator?*pIMemAlloc,??

????????ALLOCATOR_PROPERTIES?*pProperties);??

??

????//獲得媒體類型??

????//在枚舉器中枚舉支持的媒體類型時調用此函數得到PIN支持的媒體類型??

????//此函數設置pmt的各個成員，因此，由此函數的內容覺得PIN支持什么媒體類型??

????HRESULT?GetMediaType(int?iPosition,?CMediaType?*pmt);??

??

????//檢測是否支持參數傳入的媒體類型??

????HRESULT?CheckMediaType(const?CMediaType?*pMediaType);??

??

????//這是質量控制接口，最簡單的源Filter不需要質量控制??

????STDMETHODIMP?Notify(IBaseFilter?*pSelf,?Quality?q)??

????{??

????????return?E_FAIL;??

????}??

??

private:??

????BYTE*?m_pData[3];//存儲圖片數據??

????int?m_nWidth;//圖片的寬??

????int?m_nHeight;//圖片的高??

????int?m_nImageSize;//圖片數據的大小??

????int?m_nCount;//計數器，用來切換圖片數據的緩沖區??

};??

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3.實現CMySourceFilter類。這個類只有兩個函數需要編寫，很簡單。

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[cpp]?view plaincopyprint?

//CMySourceFilter.cpp??

CUnknown*?CMySourceFilter::CreateInstance(LPUNKNOWN?lpunk,?HRESULT?*phr)??

{??

????//實例化函數的工作就是實例化一個源Filter的對象??

?????CUnknown?*punk?=?new?CMySourceFilter(lpunk,phr);??

?????if?(punk?==?NULL)??

?????{??

?????????*phr?=?E_OUTOFMEMORY;??

?????}??

?????return?punk;??

}??

??

CMySourceFilter::CMySourceFilter(LPUNKNOWN?lpunk,?HRESULT?*phr)??

?:?CSource(L"MyFilter",lpunk,CLSID_MyFilter,phr)??

{??

????//創建一個pin的對象實例??

????//在CSourceStream的構造函數中，會把pin添加到Filter中??

????CMyOutputPin*?pOutPin?=?new?CMyOutputPin(phr,this);??

????if?(FAILED(*phr))??

????{??

????????//因此，在創建失敗的時候，要將這個pin從Filter中移除??

????????RemovePin(pOutPin);??

????????pOutPin->Release();??

????}??

}??

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4.實現CMyOutputPin類，編寫Filter主要就是寫pin。

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[cpp]?view plaincopyprint?

//MyOutputPin.cpp??

??

//構造函數??

CMyOutputPin::CMyOutputPin(HRESULT?*phr,?CSource?*pFilter)??

:?CSourceStream(L"MyFilter",phr,pFilter,L"Out")??

,?m_nWidth(0)??

,?m_nHeight(0)??

,?m_nImageSize(0)??

,?m_nCount(0)??

{??

????//把圖片讀到內存中，準備好數據??

????m_pData[0]?=?LoadBitmapFileToMemory(L"E://DirectShow//MySourceFilter//1.bmp",??

????????m_nWidth,m_nHeight,m_nImageSize);??

????m_pData[1]?=?LoadBitmapFileToMemory(L"E://DirectShow//MySourceFilter//2.bmp",??

????????m_nWidth,m_nHeight,m_nImageSize);??

????m_pData[2]?=?LoadBitmapFileToMemory(L"E://DirectShow//MySourceFilter//3.bmp",??

????????m_nWidth,m_nHeight,m_nImageSize);??

}??

??

//析構函數??

CMyOutputPin::~CMyOutputPin(void)??

{??

????//釋放內存??

????delete?[]m_pData[0];??

????delete?[]m_pData[1];??

????delete?[]m_pData[2];??

}??

??

//獲取媒體類型??

//填充pmt??

//最簡單的源Filter，因此只支持一種類型，所以iPosition為0??

HRESULT?CMyOutputPin::GetMediaType(int?iPosition,?CMediaType?*pmt)??

{??

????CheckPointer(pmt,E_POINTER);??

??

????CAutoLock?cAutoLock(m_pFilter->pStateLock());??

????if(iPosition?<?0)??

????{??

????????return?E_INVALIDARG;??

????}??

????//?Have?we?run?off?the?end?of?types???

????if(iPosition?>?0)??

????{??

????????return?VFW_S_NO_MORE_ITEMS;??

????}??

??

????//給媒體類型申請Format的空間??

????//填充每一個對象，主要是BITMAPINFOHEADER結構??

????VIDEOINFO?*pvi?=?(VIDEOINFO?*)?pmt->AllocFormatBuffer(sizeof(VIDEOINFO));??

????if(NULL?==?pvi)??

????????return(E_OUTOFMEMORY);??

??

????ZeroMemory(pvi,?sizeof(VIDEOINFO));??

????pvi->bmiHeader.biBitCount?=?24;??

????pvi->bmiHeader.biHeight?=?m_nHeight;??

????pvi->bmiHeader.biWidth?=?m_nWidth;??

????pvi->bmiHeader.biSizeImage?=?m_nImageSize;??

????pvi->bmiHeader.biPlanes?=?1;??

????pvi->bmiHeader.biSize?=?sizeof(BITMAPINFOHEADER);??

????pvi->bmiHeader.biCompression?=?BI_RGB;??

????pvi->bmiHeader.biClrImportant?=?0;??

??

????SetRectEmpty(&pvi->rcSource);??

????SetRectEmpty(&pvi->rcTarget);??

??

????pmt->SetType(&MEDIATYPE_Video);//設置主媒體類型??

????pmt->SetSubtype(&MEDIASUBTYPE_RGB24);//設置子媒體類型??

????pmt->SetFormatType(&FORMAT_VideoInfo);//設置詳細格式類型??

????pmt->SetSampleSize(m_nImageSize);//設置Sample的大小??

????pmt->SetTemporalCompression(FALSE);??

??

????return?NOERROR;??

}??

??

//檢查媒體類型??

//主要是對GetMediaType中設置的各個參數進行比較??

HRESULT?CMyOutputPin::CheckMediaType(const?CMediaType?*pMediaType)??

{??

????CheckPointer(pMediaType,E_POINTER);??

??

????if?(*(pMediaType->Type())?!=?MEDIATYPE_Video??

????????||?!(pMediaType->IsFixedSize()))??

????{??

????????return?E_INVALIDARG;??

????}??

??

????const?GUID?*SubType?=?pMediaType->Subtype();??

????if?(SubType?==?NULL)??

????{??

????????return?E_INVALIDARG;??

????}??

????if?(*SubType?!=?MEDIASUBTYPE_RGB24)??

????{??

????????return?E_INVALIDARG;??

????}??

????const?GUID*?FormatType?=?pMediaType->FormatType();??

????if?(FormatType?==?NULL)??

????{??

????????return?E_INVALIDARG;??

????}??

????if?(*FormatType?!=?FORMAT_VideoInfo)??

????{??

????????return?E_INVALIDARG;??

????}??

??

????VIDEOINFO*?pvi?=?(VIDEOINFO*)pMediaType->Format();??

????if?(pvi?==?NULL)??

????{??

????????return?E_INVALIDARG;??

????}??

????if?(pvi->bmiHeader.biBitCount?!=?24?||???

????????pvi->bmiHeader.biWidth?!=?m_nWidth?||??

????????pvi->bmiHeader.biHeight?!=?m_nHeight)??

????{??

????????return?E_INVALIDARG;??

????}??

??

????return?S_OK;??

}??

??

//協商Sample的大小??

HRESULT?CMyOutputPin::DecideBufferSize(IMemAllocator?*pIMemAlloc,?ALLOCATOR_PROPERTIES?*pProperties)??

{??

????CheckPointer(pIMemAlloc,E_POINTER);??

????CheckPointer(pProperties,E_POINTER);??

??

????CAutoLock?cAutoLock(m_pFilter->pStateLock());??

????HRESULT?hr?=?NOERROR;??

??

????VIDEOINFO?*pvi?=?(VIDEOINFO?*)?m_mt.Format();??

????//確定只有一個buffer??

????pProperties->cBuffers?=?1;??

????//設置buffer的大小??

????pProperties->cbBuffer?=?m_nImageSize;??

??

????ASSERT(pProperties->cbBuffer);??

??

????//設置屬性頁??

????ALLOCATOR_PROPERTIES?Actual;??

????hr?=?pIMemAlloc->SetProperties(pProperties,&Actual);??

????if(FAILED(hr))??

????{??

????????return?hr;??

????}??

??

????if(Actual.cbBuffer?<?pProperties->cbBuffer)??

????{??

????????return?E_FAIL;??

????}??

??

????ASSERT(Actual.cBuffers?==?1);??

????return?NOERROR;??

}??

??

//填充Sample??

HRESULT?CMyOutputPin::FillBuffer(IMediaSample?*pMediaSample)??

{??

????CheckPointer(pMediaSample,E_POINTER);??

????BYTE*?pData?=?NULL;??

????long?lDataSize?=?0;??

??

????//獲得Sample中存放數據的地址??

????pMediaSample->GetPointer(&pData);??

????//取得Sample分配的內存大小??

????lDataSize?=?pMediaSample->GetSize();??

??

????ZeroMemory(pData,lDataSize);??

????//把當前需要顯示的數據拷貝到內存中??

????CopyMemory(pData,m_pData[m_nCount%3],m_nImageSize);??

??

????//設置時間戳??

????REFERENCE_TIME?start?=?TS_ONE?*?m_nCount;??

????REFERENCE_TIME?stop?=?TS_ONE?+?start;??

????pMediaSample->SetTime(&start,&stop);??

??

????//準備下一幀數據??

????m_nCount++;??

??

????pMediaSample->SetSyncPoint(TRUE);??????

??

????return?NOERROR;??

}??

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LoadBitmapFileToMemory函數的實現

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[cpp]?view plaincopyprint?

BYTE*?LoadBitmapFileToMemory(TCHAR*?pFileName,?int&?nWidth,?int&?nHeight,?int&?nImageDataSize)??

{??

????HBITMAP?hBitmap?=?(HBITMAP)LoadImage(?NULL,?pFileName,?IMAGE_BITMAP,?0,?0,??

????????LR_CREATEDIBSECTION?|?LR_DEFAULTSIZE?|?LR_LOADFROMFILE?);??

??

????if(hBitmap?==?NULL)??

????????return?NULL;??

??

????HDC?hDC?=?CreateCompatibleDC(NULL);??

????HBITMAP?hOldBitmap?=?(HBITMAP)SelectObject(hDC,?hBitmap);??

??

????BITMAP?bmp;??

????GetObject(hBitmap,?sizeof(bmp),?&bmp);??

??

????BITMAPINFOHEADER?bih?=?{0};//位圖信息頭??

????bih.biBitCount?=?bmp.bmBitsPixel;//每個像素字節大小??

????bih.biCompression?=?BI_RGB;??

????bih.biHeight?=?bmp.bmHeight;//高度??

????bih.biPlanes?=?1;??

????bih.biSize?=?sizeof(BITMAPINFOHEADER);??

????bih.biSizeImage?=?bmp.bmWidthBytes?*?bmp.bmHeight;//圖像數據大小??

????bih.biWidth?=?bmp.bmWidth;//寬度??

??

????nImageDataSize?=?bmp.bmWidthBytes?*?bmp.bmHeight;??

????byte?*?p?=?new?byte[nImageDataSize];//申請內存保存位圖數據??

????GetDIBits(hDC,?hBitmap,?0,?bmp.bmHeight,?p,??

????????(LPBITMAPINFO)?&bih,?DIB_RGB_COLORS);//獲取位圖數據??

??

????SelectObject(hDC,?hOldBitmap);??

????DeleteObject(hBitmap);??

????DeleteDC(hDC);??

??

????nWidth?=?bmp.bmWidth;??

????nHeight?=?bmp.bmHeight;??

??

????return?p;??

}??

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5.主要的工作已經做完了，功能已經實現，接下來就是生成Filter。

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//MySourceFilter.h??

//動態庫工程自然也要有入口函數（固定格式）??

????extern?"C"?BOOL?WINAPI?DllEntryPoint(HINSTANCE,?ULONG,?LPVOID);??

??

????BOOL?APIENTRY?DllMain(HANDLE?hModule,???

????????DWORD??dwReason,???

????????LPVOID?lpReserved)??

????{??

????????return?DllEntryPoint((HINSTANCE)(hModule),?dwReason,?lpReserved);??

????}??

//組件就少不了注冊與注銷函數（固定格式）??

STDAPI?DllRegisterServer()??

????{??

????????return?AMovieDllRegisterServer2(TRUE);??

??

????}??

STDAPI?DllUnregisterServer()??

????{??

????????return?AMovieDllRegisterServer2(FALSE);??

??

????}??

??

//組件，就要有GUID（通過工具創建）??

DEFINE_GUID(CLSID_MyFilter,???

????????????0x159386e0,?0x5193,?0x48ac,?0x8a,?0x57,?0x17,?0x88,?0xc7,?0x33,?0x40,?0xc1);??

??

//以下是注冊信息的模版，寫了注釋的地方是我們需要填寫的，其他的采用默認??

const?AMOVIESETUP_MEDIATYPE?sudOpPinTypes?=??

{??

????&MEDIATYPE_Video,???????//?Major?type??

????&MEDIASUBTYPE_NULL??????//?Minor?type??

};??

??

const?AMOVIESETUP_PIN?sudOpPin?=??

{??

????L"Output",???????????????

????FALSE,???????????????????

????TRUE,?????????????????????

????FALSE,????????????????????

????FALSE,????????????????????

????&CLSID_NULL,?????????????

????NULL,????????????????????

????1,????????????????????????

????&sudOpPinTypes?};???????

??

????const?AMOVIESETUP_FILTER?sudBallax?=??

????{??

????????&CLSID_MyFilter,????//?自定義的GUID??

????????L"MyFilter",???????//?Filter的名字??

????????MERIT_DO_NOT_USE,?????????

????????1,????????????????????????

????????&sudOpPin???????????

????};??

??

??

????//?COM?global?table?of?objects?in?this?dll??

??

????CFactoryTemplate?g_Templates[]?=?{??

????????{?L"MyFilter"//Filter的名字??

????????,?&CLSID_MyFilter//自定義的GUID??

????????,?CMySourceFilter::CreateInstance//Filter的實例化接口??

????????,?NULL??

????????,?&sudBallax?}??

????};??

????int?g_cTemplates?=?sizeof(g_Templates)?/?sizeof(g_Templates[0]);??

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6.MySourceFilter.def文件的內容

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LIBRARY?"MySourceFilter.ax"??

??

EXPORTS??

????????????DllMain?????????????????PRIVATE??

????????????DllGetClassObject???????PRIVATE??

????????????DllCanUnloadNow?????????PRIVATE??

????????????DllRegisterServer???????PRIVATE??

????????????DllUnregisterServer?????PRIVATE??

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7.注意

1）包含頭文件?#include <initguid.h>，否則有可能提示 error LNK2001: 無法解析的外部符號 _CLSID_MyFilter

2）包含導出庫#pragma comment(lib, "winmm")

3）包含導入庫#pragma comment(lib, "strmbase.lib")，Debug下包含#pragma comment(lib, "strmbasd.lib")

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8.大功告成。調用regsvr32注冊Filter。使用GraphEdit調試Filter。（VS2005）

在工程的屬性中選擇調試，在命令中填入GraphEdit的完整路徑，把Filter的工程作為啟動項。按下F5，在運行的GraphEdit中選擇我們的Filter，Render pin，就可以看到一條完整的鏈路，然后run，效果出來了，三幅圖片輪流顯示在窗口中。

轉載于:https://www.cnblogs.com/signal/p/4094102.html

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