关键概念 {#关键概念}

filter
filter graph
filter graph manager
filter interface （COM interface）
filter Pin（输入输出端子）Pin Property及Pin MediaType
系统设备枚举用于选择设备
GraphEdit工具使用
Video Capture及ICaptureGraphBuilder2使用
视频采集设备、VFW和WDM及KsProxy
使用驱动自带的设置窗口控制设备及视频设置
IAMStreamConfig：设置帧率、视频格式（MJPEG/YUYV）、视频大小
IAMVideoProcAmp：设置增益、白平衡等
IAMCameraControl：相机控制，控制曝光、调焦
Smart Tee（智能三通）实现Capture Pin一分二，分成Capture和Preview
同时预览和抓图
Sample Grabber抓图
保存filter graph文件
视频渲染无窗模式，渲染到MFC控件上
各种filter和COM对象都有很多接口，需要查官方文档才能知道如何使用，一定要学会查官方文档！！！

视频逐行扫描和隔行扫描 {#视频逐行扫描和隔行扫描}

逐行扫描：图像从左至右，从上到下输出一张完整的图片
隔行扫描：1. 一帧分为两个场来扫描；2. 两帧分为奇偶隔行扫描
两帧奇偶隔行扫描可以节省一半的带宽，但是可能会发生交错（interlaced），尤其是运动图像。 VIDEOINFOHEADER2 比VIDEOINFOHEADER提供了更多关于interlaced的信息。

在输出MJPG预览的设备中，中间需要插入MJPEG Decompressor Filter才能将视频渲染到显卡上，MJPEG Decompressor Filter输出标准的RGB图像。

代码示例 {#代码示例}

有窗口模式的视频预览及抓图示例代码如下所示：

头文件（preview_wnd.h） {#头文件（preview-wnd-h）}

|---------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | // preview_wnd.h #include <afxwin.h> #include <tchar.h> #include <dshow.h> #include <iostream> #include <fstream> using namespace std; extern HWND hwnd; extern IMediaControl *pControl; extern IMediaEventEx *pEvent; // window messages #define WM_FGNOTIFY WM_USER + 1 int show(); void ShowFilterInfo(IBaseFilter *filter); void ShowGUID(GUID *guid); |

实现文件（preview_wnd.cpp） {#实现文件（preview-wnd-cpp）}

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527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 | // preview_wnd.cpp /** * 构建默认的usb设备视频预览 * * 编译 cl preview_app.cpp preview_wnd.cpp SaveGraphFile.cpp Strmiids.lib ole32.lib OleAut32.lib user32.lib */ #include "preview_wnd.h" #include <afxwin.h> #include <tchar.h> #include <dshow.h> #include <iostream> using namespace std; #include <dvdmedia.h> #include "SaveGraphFile.h" IMediaControl *pControl = NULL; IMediaEventEx *pEvent = NULL; EXTERN_C const CLSID CLSID_SampleGrabber; #ifdef __cplusplus class DECLSPEC_UUID("C1F400A0-3F08-11d3-9F0B-006008039E37") SampleGrabber; #endif EXTERN_C const IID IID_ISampleGrabberCB; #if defined(__cplusplus) && !defined(CINTERFACE) MIDL_INTERFACE("0579154A-2B53-4994-B0D0-E773148EFF85") ISampleGrabberCB : public IUnknown { public: virtual HRESULT STDMETHODCALLTYPE SampleCB( double SampleTime, IMediaSample *pSample) = 0; virtual HRESULT STDMETHODCALLTYPE BufferCB( double SampleTime, BYTE *pBuffer, long BufferLen) = 0; }; #else /* C style interface */ typedef struct ISampleGrabberCBVtbl { BEGIN_INTERFACE HRESULT(STDMETHODCALLTYPE *QueryInterface) ( ISampleGrabberCB *This, /* [in] */ REFIID riid, /* [iid_is][out] */ void **ppvObject); ULONG(STDMETHODCALLTYPE *AddRef) ( ISampleGrabberCB *This); ULONG(STDMETHODCALLTYPE *Release) ( ISampleGrabberCB *This); HRESULT(STDMETHODCALLTYPE *SampleCB) ( ISampleGrabberCB *This, double SampleTime, IMediaSample *pSample); HRESULT(STDMETHODCALLTYPE *BufferCB) ( ISampleGrabberCB *This, double SampleTime, BYTE *pBuffer, long BufferLen); END_INTERFACE } ISampleGrabberCBVtbl; interface ISampleGrabberCB { CONST_VTBL struct ISampleGrabberCBVtbl *lpVtbl; }; #ifdef COBJMACROS #define ISampleGrabberCB_QueryInterface(This, riid, ppvObject) \ (This)->lpVtbl->QueryInterface(This, riid, ppvObject) #define ISampleGrabberCB_AddRef(This) \ (This)->lpVtbl->AddRef(This) #define ISampleGrabberCB_Release(This) \ (This)->lpVtbl->Release(This) #define ISampleGrabberCB_SampleCB(This, SampleTime, pSample) \ (This)->lpVtbl->SampleCB(This, SampleTime, pSample) #define ISampleGrabberCB_BufferCB(This, SampleTime, pBuffer, BufferLen) \ (This)->lpVtbl->BufferCB(This, SampleTime, pBuffer, BufferLen) #endif /* COBJMACROS */ #endif /* C style interface */ #ifndef __ISampleGrabber_INTERFACE_DEFINED__ #define __ISampleGrabber_INTERFACE_DEFINED__ /* interface ISampleGrabber */ /* [unique][helpstring][local][uuid][object] */ EXTERN_C const IID IID_ISampleGrabber; #if defined(__cplusplus) && !defined(CINTERFACE) MIDL_INTERFACE("6B652FFF-11FE-4fce-92AD-0266B5D7C78F") ISampleGrabber : public IUnknown { public: virtual HRESULT STDMETHODCALLTYPE SetOneShot( BOOL OneShot) = 0; virtual HRESULT STDMETHODCALLTYPE SetMediaType( const AM_MEDIA_TYPE *pType) = 0; virtual HRESULT STDMETHODCALLTYPE GetConnectedMediaType( AM_MEDIA_TYPE * pType) = 0; virtual HRESULT STDMETHODCALLTYPE SetBufferSamples( BOOL BufferThem) = 0; virtual HRESULT STDMETHODCALLTYPE GetCurrentBuffer( /* [out][in] */ long *pBufferSize, /* [out] */ long *pBuffer) = 0; virtual HRESULT STDMETHODCALLTYPE GetCurrentSample( /* [retval][out] */ IMediaSample * *ppSample) = 0; virtual HRESULT STDMETHODCALLTYPE SetCallback( ISampleGrabberCB * pCallback, long WhichMethodToCallback) = 0; }; #else /* C style interface */ typedef struct ISampleGrabberVtbl { BEGIN_INTERFACE HRESULT(STDMETHODCALLTYPE *QueryInterface) ( ISampleGrabber *This, /* [in] */ REFIID riid, /* [iid_is][out] */ void **ppvObject); ULONG(STDMETHODCALLTYPE *AddRef) ( ISampleGrabber *This); ULONG(STDMETHODCALLTYPE *Release) ( ISampleGrabber *This); HRESULT(STDMETHODCALLTYPE *SetOneShot) ( ISampleGrabber *This, BOOL OneShot); HRESULT(STDMETHODCALLTYPE *SetMediaType) ( ISampleGrabber *This, const AM_MEDIA_TYPE *pType); HRESULT(STDMETHODCALLTYPE *GetConnectedMediaType) ( ISampleGrabber *This, AM_MEDIA_TYPE *pType); HRESULT(STDMETHODCALLTYPE *SetBufferSamples) ( ISampleGrabber *This, BOOL BufferThem); HRESULT(STDMETHODCALLTYPE *GetCurrentBuffer) ( ISampleGrabber *This, /* [out][in] */ long *pBufferSize, /* [out] */ long *pBuffer); HRESULT(STDMETHODCALLTYPE *GetCurrentSample) ( ISampleGrabber *This, /* [retval][out] */ IMediaSample **ppSample); HRESULT(STDMETHODCALLTYPE *SetCallback) ( ISampleGrabber *This, ISampleGrabberCB *pCallback, long WhichMethodToCallback); END_INTERFACE } ISampleGrabberVtbl; interface ISampleGrabber { CONST_VTBL struct ISampleGrabberVtbl *lpVtbl; }; #ifdef COBJMACROS #define ISampleGrabber_QueryInterface(This, riid, ppvObject) \ (This)->lpVtbl->QueryInterface(This, riid, ppvObject) #define ISampleGrabber_AddRef(This) \ (This)->lpVtbl->AddRef(This) #define ISampleGrabber_Release(This) \ (This)->lpVtbl->Release(This) #define ISampleGrabber_SetOneShot(This, OneShot) \ (This)->lpVtbl->SetOneShot(This, OneShot) #define ISampleGrabber_SetMediaType(This, pType) \ (This)->lpVtbl->SetMediaType(This, pType) #define ISampleGrabber_GetConnectedMediaType(This, pType) \ (This)->lpVtbl->GetConnectedMediaType(This, pType) #define ISampleGrabber_SetBufferSamples(This, BufferThem) \ (This)->lpVtbl->SetBufferSamples(This, BufferThem) #define ISampleGrabber_GetCurrentBuffer(This, pBufferSize, pBuffer) \ (This)->lpVtbl->GetCurrentBuffer(This, pBufferSize, pBuffer) #define ISampleGrabber_GetCurrentSample(This, ppSample) \ (This)->lpVtbl->GetCurrentSample(This, ppSample) #define ISampleGrabber_SetCallback(This, pCallback, WhichMethodToCallback) \ (This)->lpVtbl->SetCallback(This, pCallback, WhichMethodToCallback) #endif /* COBJMACROS */ #endif /* C style interface */ HRESULT STDMETHODCALLTYPE ISampleGrabber_SetOneShot_Proxy( ISampleGrabber *This, BOOL OneShot); void __RPC_STUB ISampleGrabber_SetOneShot_Stub( IRpcStubBuffer *This, IRpcChannelBuffer *_pRpcChannelBuffer, PRPC_MESSAGE _pRpcMessage, DWORD *_pdwStubPhase); HRESULT STDMETHODCALLTYPE ISampleGrabber_SetMediaType_Proxy( ISampleGrabber *This, const AM_MEDIA_TYPE *pType); void __RPC_STUB ISampleGrabber_SetMediaType_Stub( IRpcStubBuffer *This, IRpcChannelBuffer *_pRpcChannelBuffer, PRPC_MESSAGE _pRpcMessage, DWORD *_pdwStubPhase); HRESULT STDMETHODCALLTYPE ISampleGrabber_GetConnectedMediaType_Proxy( ISampleGrabber *This, AM_MEDIA_TYPE *pType); void __RPC_STUB ISampleGrabber_GetConnectedMediaType_Stub( IRpcStubBuffer *This, IRpcChannelBuffer *_pRpcChannelBuffer, PRPC_MESSAGE _pRpcMessage, DWORD *_pdwStubPhase); HRESULT STDMETHODCALLTYPE ISampleGrabber_SetBufferSamples_Proxy( ISampleGrabber *This, BOOL BufferThem); void __RPC_STUB ISampleGrabber_SetBufferSamples_Stub( IRpcStubBuffer *This, IRpcChannelBuffer *_pRpcChannelBuffer, PRPC_MESSAGE _pRpcMessage, DWORD *_pdwStubPhase); HRESULT STDMETHODCALLTYPE ISampleGrabber_GetCurrentBuffer_Proxy( ISampleGrabber *This, /* [out][in] */ long *pBufferSize, /* [out] */ long *pBuffer); void __RPC_STUB ISampleGrabber_GetCurrentBuffer_Stub( IRpcStubBuffer *This, IRpcChannelBuffer *_pRpcChannelBuffer, PRPC_MESSAGE _pRpcMessage, DWORD *_pdwStubPhase); HRESULT STDMETHODCALLTYPE ISampleGrabber_GetCurrentSample_Proxy( ISampleGrabber *This, /* [retval][out] */ IMediaSample **ppSample); void __RPC_STUB ISampleGrabber_GetCurrentSample_Stub( IRpcStubBuffer *This, IRpcChannelBuffer *_pRpcChannelBuffer, PRPC_MESSAGE _pRpcMessage, DWORD *_pdwStubPhase); HRESULT STDMETHODCALLTYPE ISampleGrabber_SetCallback_Proxy( ISampleGrabber *This, ISampleGrabberCB *pCallback, long WhichMethodToCallback); void __RPC_STUB ISampleGrabber_SetCallback_Stub( IRpcStubBuffer *This, IRpcChannelBuffer *_pRpcChannelBuffer, PRPC_MESSAGE _pRpcMessage, DWORD *_pdwStubPhase); #endif /* __ISampleGrabber_INTERFACE_DEFINED__ */ EXTERN_C const CLSID CLSID_NullRenderer; #ifdef __cplusplus class DECLSPEC_UUID("C1F400A4-3F08-11d3-9F0B-006008039E37") NullRenderer; #endif // class CDeviceController : public CFrameWnd // { // }; class CSampleGrabberCB : public ISampleGrabberCB { public: STDMETHODIMP_(ULONG) AddRef() { return 2; } STDMETHODIMP_(ULONG) Release() { return 1; } STDMETHODIMP QueryInterface(REFIID iid, void **ppv) { if (NULL == ppv) return E_POINTER; *ppv = NULL; if (IID_IUnknown == iid) { *ppv = (IUnknown *)this; AddRef(); return S_OK; } else if (IID_ISampleGrabberCB == iid) { *ppv = (ISampleGrabberCB *)this; AddRef(); return S_OK; } return E_NOINTERFACE; } STDMETHODIMP BufferCB(double dblSampleTime, BYTE *pBuffer, long lBufferSize) { cout << "BufferCB SampleTime " << dec << dblSampleTime << ", BufferSize " << lBufferSize << endl; static char path[100]; static int index = 0; static int m_index = 0; sprintf(path, "pic/%d_%d.jpg", m_index, index++); FILE *file = fopen((const char *)path, "wb"); fwrite(pBuffer, lBufferSize, 1, file); fclose(file); return S_OK; } HRESULT STDMETHODCALLTYPE SampleCB(double SampleTime, IMediaSample *pSample) { cout << "SampleCB SampleTime " << dec << SampleTime << endl; return S_OK; } }; void ShowGUID(GUID *guid) { cout << hex << guid->Data1 << "-" << guid->Data2 << "-" << guid->Data3 << "-"; for (int i = 0; i < 8; i++) { cout << hex << guid->Data4[i]; } cout << endl; } void ShowFilterInfo(IBaseFilter *filter) { FILTER_INFO finfo; HRESULT hr = filter->QueryFilterInfo(&finfo); if (S_OK == hr) // cout << finfo.achName << endl; { CLSID clsid; filter->GetClassID(&clsid); cout << "filter class id " << hex << clsid.Data1 << "-" << clsid.Data2 << "-" << clsid.Data3 << endl; _tprintf(_T("filter name %ws\r\n"), finfo.achName); if (finfo.pGraph != NULL) { finfo.pGraph->Release(); } } else { cout << "Show Filter Info Failed " << hr << endl; } } void ShowPinInfo(IPin *pin) { PIN_INFO info; HRESULT hr = pin->QueryPinInfo(&info); if (S_OK == hr) { _tprintf(_T("pin name %ws,direction %d\r\n"), info.achName, info.dir); if (NULL != info.pFilter) { ShowFilterInfo(info.pFilter); info.pFilter->Release(); } } else { cout << "get pin info failed" << endl; } } BOOL ChooseDevice(TCHAR *szDeviceName, IBaseFilter **pFilter) { HRESULT hr; ICreateDevEnum *pSysDevEnum = NULL; // 创建并默认初始化一个指定CLSID关联的类的对象 // 创建SystemDeviceEnum对象 hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, (void **)&pSysDevEnum); IEnumMoniker *pEnumCat = NULL; // 创建关联的设备类型枚举对象，枚举视频输入设备 hr = pSysDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &pEnumCat, 0); IMoniker *pMoniker = NULL; ULONG cFected; // 循环获取设备 while (pEnumCat->Next(1, &pMoniker, &cFected) == S_OK) { IPropertyBag *pPropBag = NULL; // 获取设备信息 hr = pMoniker->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pPropBag); if (SUCCEEDED(hr)) { // To retrieve the filter's friendly name, do the following: VARIANT varName; VariantInit(&varName); hr = pPropBag->Read(L"FriendlyName", &varName, 0); if (SUCCEEDED(hr)) { // Display the name in your UI somehow. printf("%S\n", varName.bstrVal); } VariantClear(&varName); // 获取封装设备的Filter hr = pMoniker->BindToObject(NULL, NULL, IID_IBaseFilter, (void **)pFilter); pPropBag->Release(); break; } } pEnumCat->Release(); pSysDevEnum->Release(); return TRUE; } int show() { HRESULT hr = CoInitialize(NULL); if (FAILED(hr)) { // init COM failed cout << "init COM failed" << endl; return 0; } // 创建Filter Graph Manager对象 IGraphBuilder *pGraph; // 查找类标识为CLSID_FilterGraph的COM组件，使用改组件创建接口标识符为IID_IGraphBuilder的进程内组件对象pGraph hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void **)&pGraph); if (FAILED(hr)) { // 创建 Filter Graph return 0; } /** * 获取Filter Graph Manager的两个接口 * 1. IMediaControl 控制filter graph的启动和停止 * 2. IMediaEvent 从Filter Graph Manager获取事件，例如视频文件播放完毕事件 * */ hr = pGraph->QueryInterface(IID_IMediaControl, (void **)&pControl); hr = pGraph->QueryInterface(IID_IMediaEvent, (void **)&pEvent); ICaptureGraphBuilder2 *pBuild = NULL; hr = CoCreateInstance(CLSID_CaptureGraphBuilder2, NULL, CLSCTX_INPROC_SERVER, IID_ICaptureGraphBuilder2, (void **)&pBuild); if (FAILED(hr)) return 0; pBuild->SetFiltergraph(pGraph); // build graph IBaseFilter *pDeviceFilter = NULL; ChooseDevice(_T("SEMIC Camera"), &pDeviceFilter); cout << "Create Device Filter " << hex << pDeviceFilter << endl; pGraph->AddFilter(pDeviceFilter, L"SEMIC Camera"); ShowFilterInfo(pDeviceFilter); IEnumPins *pDeviceEnumPins = NULL; // 设置输出视频格式及参数 hr = pDeviceFilter->EnumPins(&pDeviceEnumPins); IPin *pDeviceOutPin = NULL; while (pDeviceEnumPins->Next(1, &pDeviceOutPin, NULL) == S_OK) { PIN_DIRECTION pdir; pDeviceOutPin->QueryDirection(&pdir); if (PIN_DIRECTION::PINDIR_OUTPUT == pdir) { break; } pDeviceOutPin->Release(); } // GUID pSelectFormat = FORMAT_VideoInfo; GUID pSelectVideoType = MEDIASUBTYPE_MJPG; LONG pSelectWidth = 1920L; LONG pSelectHeight = 1080L; int pSelectFrameRate = 10; AM_MEDIA_TYPE *pSelectMediaType = NULL; AM_MEDIA_TYPE *pMediaType = NULL; IAMStreamConfig *pStreamConfig = NULL; hr = pDeviceOutPin->QueryInterface(IID_IAMStreamConfig, (void **)&pStreamConfig); if (hr == S_OK) { int piCount, piSize; hr = pStreamConfig->GetNumberOfCapabilities(&piCount, &piSize); cout << "show media type : " << endl; for (int i = 0; i < piCount; i++) { VIDEO_STREAM_CONFIG_CAPS scc; pStreamConfig->GetStreamCaps(i, &pMediaType, reinterpret_cast<BYTE *>(&scc)); // 获取所有设备支持的多媒体格式 // hr = pStreamConfig->GetFormat(&pMediaType); // pMediaType->formattype; // ShowGUID(&pMediaType->formattype); // ShowGUID(&pMediaType->majortype); // ShowGUID(&pMediaType->subtype); // ShowGUID(&pMediaType->subtype); // pStreamConfig->SetFormat() if (FORMAT_VideoInfo == pMediaType->formattype) { VIDEOINFOHEADER *pvideoInfo = (VIDEOINFOHEADER *)pMediaType->pbFormat; cout << "format videoinfo frame type "; if (MEDIASUBTYPE_YUY2 == pMediaType->subtype) { cout << "YUY2 , "; } else if (MEDIASUBTYPE_MJPG == pMediaType->subtype) { cout << "MJPG , "; } else { ShowGUID(&pMediaType->subtype); } cout << " height " << dec << pvideoInfo->bmiHeader.biHeight << " width " << pvideoInfo->bmiHeader.biWidth; // << endl; cout << ", frame rate " << dec << 10000000 / pvideoInfo->AvgTimePerFrame << endl; if (pSelectFormat == pMediaType->formattype && pSelectVideoType == pMediaType->subtype && pSelectHeight == pvideoInfo->bmiHeader.biHeight && pSelectWidth == pvideoInfo->bmiHeader.biWidth) { pSelectMediaType = pMediaType; } // cout << " frame size " << dec << pvideoInfo->bmiHeader.biSizeImage << endl; // 修改帧率 // int _frame_rate = 5; // pvideoInfo->AvgTimePerFrame = 10000000 / _frame_rate; // pvideoInfo->dwBitRate = pvideoInfo->bmiHeader.biSizeImage * 8 * _frame_rate; // pStreamConfig->SetFormat(pMediaType); } else if (FORMAT_VideoInfo2 == pMediaType->formattype) { VIDEOINFOHEADER2 *pvideoInfo = (VIDEOINFOHEADER2 *)pMediaType->pbFormat; cout << "format videoinfo2 frame type "; if (MEDIASUBTYPE_YUY2 == pMediaType->subtype) { cout << "YUY2 , "; } else if (MEDIASUBTYPE_MJPG == pMediaType->subtype) { cout << "MJPG , "; } else { ShowGUID(&pMediaType->subtype); } cout << " height " << dec << pvideoInfo->bmiHeader.biHeight << " width " << pvideoInfo->bmiHeader.biWidth; // << endl; cout << ", frame rate " << dec << 10000000 / pvideoInfo->AvgTimePerFrame << endl; if (pSelectFormat == pMediaType->formattype && pSelectVideoType == pMediaType->subtype && pSelectHeight == pvideoInfo->bmiHeader.biHeight && pSelectWidth == pvideoInfo->bmiHeader.biWidth) { pSelectMediaType = pMediaType; } } else { cout << " other video format type "; ShowGUID(&pMediaType->formattype); } } } hr = pStreamConfig->SetFormat(pSelectMediaType); cout << " Set StreamConfig Media Format " << dec << hr << endl; pStreamConfig->Release(); // 添加smart tee ，分成两路，一路预览，一路抓图 IBaseFilter *pSmartTee = NULL; // hr = CoCreateInstance(CLSID_SmartTee, NULL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, (void **)&pSmartTee); // cout << " Create Smart Tee " << hex << hr << endl; // pGraph->AddFilter(pDeviceFilter, L"Smart Tee"); IBaseFilter *pNullFilter = NULL; hr = CoCreateInstance(CLSID_NullRenderer, NULL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, (LPVOID *)&pNullFilter); pGraph->AddFilter(pNullFilter, L"NULL Filter"); // RenderStream 若filter没有preview out pin，只有capture out pin则会插入一个smart tee filter；若没有指定要连接的目标则默认为video/video render filter hr = pBuild->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, pDeviceFilter, NULL, NULL); // hr = pBuild->RenderStream(&PIN_CATEGORY_CAPTURE, &MEDIATYPE_Video, pDeviceFilter, NULL, pSmartTee); cout << " RenderStream 1 " << hex << hr << endl; // hr = pBuild->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, pSmartTee, NULL, NULL); // cout << " RenderStream 2 " << hex << hr << endl; // hr = pBuild->RenderStream(&PIN_CATEGORY_CAPTURE, &MEDIATYPE_Video, pSmartTee, NULL, pNullFilter); // cout << " RenderStream 3 " << hex << hr << endl; // 查找插入的smart tee filter hr = pBuild->FindInterface(&LOOK_DOWNSTREAM_ONLY, &MEDIATYPE_Video, pDeviceFilter, IID_IBaseFilter, (void **)&pSmartTee); cout << " FindInterface 1 " << hex << hr << " Smart Tee : " << pSmartTee << endl; ShowFilterInfo(pSmartTee); // hr = pBuild->FindInterface(NULL, &MEDIATYPE_Video, pDeviceFilter, IID_IBaseFilter, (void **)&pSmartTee); // cout << " FindInterface 1 " << hex << hr << " Smart Tee : " << pSmartTee << endl; // CLSID_MjpegDec; // IBaseFilter *pRender = NULL; // hr = pBuild->FindInterface(NULL, &MEDIATYPE_Video, pSmartTee, IID_IBaseFilter, (void **)&pRender); CLSID slcid; hr = pSmartTee->GetClassID(&slcid); if (hr == S_OK) cout << hex << slcid.Data1 << "-" << slcid.Data2 << "-" << slcid.Data3 << endl; else { cout << "get class id failed" << endl; } IPin *pPrev = NULL; IEnumPins *pEnumPins = NULL; hr = pSmartTee->EnumPins(&pEnumPins); while (pEnumPins->Next(1, &pPrev, NULL) == S_OK) { PIN_DIRECTION pDir; pPrev->QueryDirection(&pDir); if (pDir == PINDIR_OUTPUT) { LPWSTR pId; pPrev->QueryId(&pId); // cout << pId << endl; _tprintf(_T("pin id : %ws , direction %d\r\n"), pId, pDir); // PIN_INFO pPinInfo; // pPrev->QueryPinInfo(&pPinInfo); pPrev->Release(); // ShowPinInfo(pPrev); } /* code */ } pEnumPins->Release(); // IPin * pNextPin = NULL; // IBaseFilter * pNextFilter = NULL; // ULONG pins=1; // pPrev->QueryInternalConnections(&pNextPin,&pins); // cout <<"start show next pin "<<endl; // ShowPinInfo(pPrev); // ShowPinInfo(pNextPin); // pPrev->Release(); // pBuild-> // FILTER_INFO finfo; // pSmartTee->QueryFilterInfo(&finfo); // cout << finfo.achName << endl; // grabber sample IBaseFilter *pGrabberF = NULL; ISampleGrabber *pGrabber = NULL; hr = CoCreateInstance(CLSID_SampleGrabber, NULL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, (void **)&pGrabberF); cout << " Create Sample Grabber " << hex << hr << endl; hr = pGraph->AddFilter(pGrabberF, L"Sample Grabber"); cout << " add grabber filter " << hex << hr << endl; hr = pGrabberF->QueryInterface(IID_ISampleGrabber, (void **)&pGrabber); cout << "grabber filter query interface " << hex << hr << endl; // 设置允许的视频格式 // AM_MEDIA_TYPE mt; // ZeroMemory(&mt, sizeof(AM_MEDIA_TYPE)); // mt.majortype = MEDIATYPE_Video; // mt.subtype = MEDIASUBTYPE_MJPG; // mt.formattype = FORMAT_VideoInfo; // hr = pGrabber->SetMediaType(&mt); // 在使用前必须设置多媒体类型 hr = pGrabber->SetMediaType(pSelectMediaType); cout << " Set Media Type " << dec << hr << endl; // RenderStream 会查找符合条件的未连接的PIN进行连接 hr = pBuild->RenderStream(NULL, &MEDIATYPE_Video, pSmartTee, pGrabberF, pNullFilter); cout << " RenderStream 4 " << hex << hr << endl; // hr = pBuild->RenderStream(NULL, &MEDIATYPE_Video, pGrabberF, NULL, pNullFilter); // cout << " RenderStream 3 " << hex << hr << endl; // 保存filer graph文件，用graphedit打开 SaveGraphFile(pGraph, L"MyGraph.grf"); CSampleGrabberCB *scb = new CSampleGrabberCB; pGrabber->SetCallback(scb, 1); // hr = pBuild->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, pDeviceFilter, NULL, NULL); // if (hr != S_OK && hr != VFW_S_NOPREVIEWPIN) // { // cout << "render MEDIATYPE_Video stream failed : " << hex << hr << endl; // hr = pBuild->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Interleaved, pDeviceFilter, NULL, NULL); // if (hr == VFW_S_NOPREVIEWPIN) // { // cout << "use capture pin" << endl; // } // else if (hr != S_OK) // { // cout << "render MEDIATYPE_Interleaved stream failed : " << hex << hr << endl; // } // } // 设置视频播放窗口 IVideoWindow *pVidWin = NULL; pGraph->QueryInterface(IID_IVideoWindow, (void **)&pVidWin); pVidWin->put_Owner((OAHWND)hwnd); pVidWin->put_WindowStyle(WS_CHILD | WS_CLIPSIBLINGS); RECT rc; GetClientRect(hwnd, &rc); pVidWin->SetWindowPosition(0, 0, rc.right, rc.bottom); // 设置filter graph event pEvent->SetNotifyWindow((OAHWND)hwnd, WM_FGNOTIFY, 0); hr = pControl->Run(); cout << "start run : " << hr << endl; // // if (hr == S_OK) // Sleep(1000 * 100); // cout << "complete" << endl; // pControl->Stop(); // pControl->Release(); // pEvent->Release(); // pGraph->Release(); // CoUninitialize(); return 0; } |

主程序（main.cpp） {#主程序（main-cpp）}

程序编译 {#程序编译}

使用cl.exe进行编译，命令如下所示：

|-----------|-------------------------------------------------------------------------------------------------------------| | 1 | cl preview_app.cpp preview_wnd.cpp SaveGraphFile.cpp Strmiids.lib ole32.lib OleAut32.lib user32.lib |