Delphi USBCamera DirectShow 预览录像截图
参照：https://www.haolizi.net/example/view_37332.html
实例介绍
【实例简介】用DirectShow 的方式，视频输入设备枚举、视频支持格式枚举、视频预览、视频录像、视频截图。Delphi 源代码
【实例截图】
【核心代码】
unit untUSBCamera; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, DirectShow9, ActiveX, Dialogs, StdCtrls, ExtCtrls; type PVideoInputInfo = ^TVideoInputInfo; PVideoFormatInfo = ^TVideoFormatInfo; { 视频输入设备 } TVideoInputInfo = record id: TGUID; strName: ShortString; index: Integer; end; { 视频支持格式 } TVideoFormatInfo = record id: TGUID; iWidth, iHeight: Integer; iMod: TGUID; Frame: Int64; format: ShortString; end; type IAMStreamConfig = interface(IUnknown) ['{C6E13340-30AC-11d0-A18C-00A0C9118956}'] function SetFormat(const pmt: TAMMediaType): HResult; stdcall; function GetFormat(out ppmt: PAMMediaType): HResult; stdcall; function GetNumberOfCapabilities(out piCount, piSize: Integer): HResult; stdcall; { Delphi 声明有误，修改声明 } function GetStreamCaps(iIndex: Integer; var ppmt: PAMMediaType; pSCC: PVideoStreamConfigCaps): HResult; stdcall; end; ISampleGrabber = interface(IUnknown) ['{6B652FFF-11FE-4FCE-92AD-0266B5D7C78F}'] function SetOneShot(OneShot: BOOL): HResult; stdcall; { Delphi 声明有误，修改声明 } function SetMediaType(pType: PAMMediaType): HResult; stdcall; function GetConnectedMediaType(out pType: TAMMediaType): HResult; stdcall; function SetBufferSamples(BufferThem: BOOL): HResult; stdcall; function GetCurrentBuffer(var pBufferSize: longint; pBuffer: Pointer): HResult; stdcall; function GetCurrentSample(out ppSample: IMediaSample): HResult; stdcall; function SetCallback(pCallback: ISampleGrabberCB; WhichMethodToCallback: longint): HResult; stdcall; end; { 枚举所有视频输入设备 } procedure EnumAllUSBCamera(strsList: TStrings); { 枚举视频支持格式 } function EnumVideoFormat(const strFriendlyName: String; const intIndex: Integer; strsList: TStrings): Boolean; { 视频预览 } function USBVideoPreview(var FIGraphBuilder: IGraphBuilder; var FICaptureGraphBuilder2: ICaptureGraphBuilder2; var FSysDevEnum: IBaseFilter; var FIVideoWindow: IVideoWindow; var FIMediaControl: IMediaControl; var FISampleGrabber: ISampleGrabber; pv: PVideoInputInfo; pf: PVideoFormatInfo; pnl: TPanel; const bSnapBmp: Boolean = False): Boolean; { 视频录制 } function USBVideoRecord(var FIGraphBuilder: IGraphBuilder; var FICaptureGraphBuilder2: ICaptureGraphBuilder2; var FSysDevEnum: IBaseFilter; var FIVideoWindow: IVideoWindow; var FIMediaControl: IMediaControl; var FISampleGrabber: ISampleGrabber; pv: PVideoInputInfo; pf: PVideoFormatInfo; pnl: TPanel; const strSaveFileName: String): Boolean; implementation const IID_IPropertyBag: TGUID = '{55272A00-42CB-11CE-8135-00AA004BB851}'; c_arrVideoFormatGUID: array [0 .. 35] of PGUID = ( // @MEDIASUBTYPE_CLPL, @MEDIASUBTYPE_YUYV, @MEDIASUBTYPE_IYUV, @MEDIASUBTYPE_YVU9, @MEDIASUBTYPE_Y411, @MEDIASUBTYPE_Y41P, // @MEDIASUBTYPE_YUY2, @MEDIASUBTYPE_YVYU, @MEDIASUBTYPE_UYVY, @MEDIASUBTYPE_Y211, @MEDIASUBTYPE_YV12, @MEDIASUBTYPE_CLJR, // @MEDIASUBTYPE_IF09, @MEDIASUBTYPE_CPLA, @MEDIASUBTYPE_MJPG, @MEDIASUBTYPE_TVMJ, @MEDIASUBTYPE_WAKE, @MEDIASUBTYPE_CFCC, // @MEDIASUBTYPE_IJPG, @MEDIASUBTYPE_Plum, @MEDIASUBTYPE_DVCS, @MEDIASUBTYPE_DVSD, @MEDIASUBTYPE_MDVF, @MEDIASUBTYPE_RGB1, // @MEDIASUBTYPE_RGB4, @MEDIASUBTYPE_RGB8, @MEDIASUBTYPE_RGB565, @MEDIASUBTYPE_RGB555, @MEDIASUBTYPE_RGB24, @MEDIASUBTYPE_RGB32, // @MEDIASUBTYPE_ARGB1555, @MEDIASUBTYPE_ARGB4444, @MEDIASUBTYPE_ARGB32, @MEDIASUBTYPE_AYUV, @MEDIASUBTYPE_AI44, @MEDIASUBTYPE_IA44 // ); c_arrVideoFormatName: array [0 .. 35] of AnsiString = ( // 'CLPL', 'YUYV', 'IYUV', 'YVU9', 'Y411', 'Y41P', // 'YUY2', 'YVYU', 'UYVY', 'Y211', 'YV12', 'CLJR', // 'IF09', 'CPLA', 'MJPG', 'TVMJ', 'WAKE', 'CFCC', // 'IJPG', 'Plum', 'DVCS', 'DVSD', 'MDVF', 'RGB1', // 'RGB4', 'RGB8', 'RGB565', 'RGB555', 'RGB24', 'RGB32', // 'ARGB1555', 'ARGB4444', 'ARGB32', 'AYUV', 'AI44', 'IA44' // ); function GetMaxIndex(const strsList: TStrings; const strUSBCameraName: string): Integer; var III, Count: Integer; begin Result := 0; Count := strsList.Count; for III := 0 to Count - 1 do begin if CompareText(String(PVideoInputInfo(strsList.Objects[III])^.strName), strUSBCameraName) = 0 then begin Result := Result 1; end; end; end; function CreateFilter(gid: TGUID; FriendlyName: AnsiString; instanceIndex: Integer): IBaseFilter; var pSysDevEnum: ICreateDevEnum; pEnumCat : IEnumMoniker; pMoniker : IMoniker; cFetched : ULONG; pPropBag : IPropertyBag; bc : IBindCtx; mo : IMoniker; er : IErrorLog; ov : OleVariant; iIndex : Integer; begin Result := nil; pSysDevEnum := nil; pEnumCat := nil; pMoniker := nil; if CocreateInstance(CLSID_SystemDeviceEnum, nil, CLSCTX_INPROC, IID_ICreateDevEnum, pSysDevEnum) = S_OK then begin if pSysDevEnum.CreateClassEnumerator(gid, pEnumCat, 0) = S_OK then begin iIndex := 0; while (pEnumCat.Next(1, pMoniker, @cFetched) = S_OK) and (cFetched > 0) and (pMoniker <> nil) do begin bc := nil; mo := nil; pMoniker.BindToStorage(bc, mo, IID_IPropertyBag, pPropBag); er := nil; pPropBag.Read('FriendlyName', ov, er); if AnsiString(ov) = FriendlyName then begin if iIndex = instanceIndex then begin bc := nil; mo := nil; pMoniker.BindToObject(bc, mo, IID_IBaseFilter, Result); end; Inc(iIndex); end; pPropBag := nil; pMoniker := nil; end; end; end; pEnumCat := nil; pSysDevEnum := nil; end; function VideoMediaSubTypeToStr(mst: TGUID): AnsiString; var I: Integer; begin Result := ''; for I := 0 to 35 do if CompareMem(c_arrVideoFormatGUID[I], @mst, sizeof(TGUID)) then begin Result := c_arrVideoFormatName[I]; break; end; end; procedure FreeMediaType(mt: TAMMediaType); begin if (mt.cbFormat <> 0) then begin CoTaskMemFree(mt.pbFormat); mt.cbFormat := 0; mt.pbFormat := nil; end; if (mt.pUnk <> nil) then begin mt.pUnk := nil; end; end; procedure DeleteMediaType(pmt: PAMMediaType); begin if pmt <> nil then begin FreeMediaType(pmt^); CoTaskMemFree(pmt); end; end; function GetOutputPin(filter: IBaseFilter): IPin; var penum: IEnumPins; f : Integer; d : PIN_DIRECTION; begin Result := nil; filter.EnumPins(penum); while (penum.Next(1, Result, @f) = S_OK) and (f > 0) do begin if (Result.QueryDirection(d) = S_OK) and (d = PINDIR_OUTPUT) then begin { 找到输出接口，返回 } Exit; end; end; Result := nil; end; function StrToVideoMediaSubType(ss: AnsiString): TGUID; var I: Integer; begin Result := c_arrVideoFormatGUID[0]^; for I := 0 to 35 do if ss = c_arrVideoFormatName[I] then begin Result := c_arrVideoFormatGUID[I]^; break; end; end; function CompareGUID(const g1, g2: TGUID): Boolean; begin Result := CompareMem(@g1, @g2, sizeof(TGUID)); end; function SetMediaType(filter: IBaseFilter; Width, Height: Integer; format: AnsiString): Boolean; var pmt : PAMMediaType; piCount, piSize: Integer; I : Integer; pSCC : PVideoStreamConfigCaps; streamConfig : IAMStreamConfig; outPin : IPin; formatID : TGUID; selectedIndex : Integer; ih : PVIDEOINFOHEADER; bitRate : dword; begin Result := False; if (Width = 0) or (Height = 0) then Exit; outPin := GetOutputPin(filter); outPin.QueryInterface(IID_IAMStreamConfig, streamConfig); if assigned(streamConfig) then begin selectedIndex := -1; bitRate := 0; formatID := StrToVideoMediaSubType(format); streamConfig.GetNumberOfCapabilities(piCount, piSize); getmem(pSCC, piSize); try for I := 0 to piCount - 1 do begin streamConfig.GetStreamCaps(I, pmt, pSCC); ih := Pointer(pmt^.pbFormat); if (pSCC^.MinOutputSize.cx = Width) and (pSCC^.MinOutputSize.cy = Height) and (ih^.bmiHeader.biWidth = Width) and (ih^.bmiHeader.biheight = Height) and ((format = '') or (CompareGUID(formatID, pmt^.subtype))) and (ih^.dwBitRate > bitRate) // select format with maximum bitrate then begin selectedIndex := I; bitRate := ih^.dwBitRate; end; DeleteMediaType(pmt); end; if selectedIndex > -1 then begin streamConfig.GetStreamCaps(selectedIndex, pmt, pSCC); try streamConfig.SetFormat(pmt^); finally DeleteMediaType(pmt); end; end; finally FreeMem(pSCC); end; end; Result := True; end; { 枚举所有视频输入设备 } procedure EnumAllUSBCamera(strsList: TStrings); var SysDevEnum: ICreateDevEnum; EnumCat : IEnumMoniker; hr : Integer; Moniker : IMoniker; Fetched : ULONG; PropBag : IPropertyBag; strName : OleVariant; strGuid : OleVariant; III : Integer; puInfo : PVideoInputInfo; intIndex : Integer; begin { 创建系统枚举器对象 } hr := CocreateInstance(CLSID_SystemDeviceEnum, nil, CLSCTX_INPROC, IID_ICreateDevEnum, SysDevEnum); if hr <> S_OK then Exit; { 用指定的 Filter 目录类型创建一个枚举器，并获得 IEnumMoniker 接口； } hr := SysDevEnum.CreateClassEnumerator(CLSID_VideoInputDeviceCategory, EnumCat, 0); if hr <> S_OK then Exit; try { 释放内存 } if strsList.Count > 0 then begin for III := 0 to strsList.Count - 1 do begin FreeMem(PVideoFormatInfo(strsList.Objects[III])); end; end; strsList.Clear; { 获取指定类型目录下所有设备标识 } while (EnumCat.Next(1, Moniker, @Fetched) = S_OK) do begin Moniker.BindToStorage(nil, nil, IID_IPropertyBag, PropBag); PropBag.Read('CLSID', strGuid, nil); PropBag.Read('FriendlyName', strName, nil); New(puInfo); puInfo^.id := TGUID(strGuid); puInfo^.strName := ShortString(strName); puInfo^.index := 0; if strsList.IndexOf(strName) = -1 then begin strsList.AddObject(strName, TObject(puInfo)); end else begin { 相同名称的 USBCamera 相机，<有可能有多个名称重复的相机> } intIndex := GetMaxIndex(strsList, strName); puInfo^.index := intIndex 1; strsList.AddObject(strName format('(%d)', [puInfo^.index]), TObject(puInfo)); end; PropBag := nil; Moniker := nil; end; finally EnumCat := nil; SysDevEnum := nil; end; end; { 枚举视频支持格式 } function EnumVideoFormat(const strFriendlyName: String; const intIndex: Integer; strsList: TStrings): Boolean; var SysDevEnum : IBaseFilter; CaptureGraphBuilder2: ICaptureGraphBuilder2; iunk : IUnknown; fStreamConfig : IAMStreamConfig; piCount, piSize : Integer; III : Integer; pmt : PAMMediaType; pSCC : PVideoStreamConfigCaps; pvInfo : PVideoFormatInfo; begin Result := False; { 获取指定USB摄像头的 Filter } SysDevEnum := CreateFilter(CLSID_VideoInputDeviceCategory, AnsiString(strFriendlyName), intIndex); if SysDevEnum = nil then Exit; { 释放内存 } if strsList.Count > 0 then begin for III := 0 to strsList.Count - 1 do begin FreeMem(PVideoFormatInfo(strsList.Objects[III])); end; end; strsList.Clear; { 创建 ICaptureGraphBuilder2 接口 } if Failed(CocreateInstance(CLSID_CaptureGraphBuilder2, nil, CLSCTX_INPROC, IID_ICaptureGraphBuilder2, CaptureGraphBuilder2)) then Exit; { 获取 IID_IAMStreamConfig 接口 } if Failed(CaptureGraphBuilder2.FindInterface(nil, nil, SysDevEnum, IID_IAMStreamConfig, iunk)) then Exit; { 获取 IAMStreamConfig 媒体类型接口 } if Failed(iunk.QueryInterface(IID_IAMStreamConfig, fStreamConfig)) then Exit; if Failed(fStreamConfig.GetNumberOfCapabilities(piCount, piSize)) then Exit; if piCount <= 0 then Exit; { 枚举支持的视频格式 } pSCC := AllocMem(piSize); try for III := 0 to piCount - 1 do begin if fStreamConfig.GetStreamCaps(III, pmt, pSCC) = S_OK then begin try New(pvInfo); { 注意释放内存 } pvInfo^.Frame := PVIDEOINFOHEADER(pmt^.pbFormat)^.AvgTimePerFrame; pvInfo^.id := pmt^.formattype; pvInfo^.iWidth := pSCC^.MaxOutputSize.cx; pvInfo^.iHeight := pSCC^.MaxOutputSize.cy; pvInfo^.iMod := pmt^.subtype; pvInfo^.format := VideoMediaSubTypeToStr(pmt^.subtype); strsList.AddObject(format('类型：%s 分辨率：%4d×%4d', [pvInfo^.format, pvInfo^.iWidth, pvInfo^.iHeight]), TObject(pvInfo)); finally DeleteMediaType(pmt); end; end; end; finally FreeMem(pSCC); end; SysDevEnum := nil; CaptureGraphBuilder2 := nil; fStreamConfig := nil; Result := True; end; function CommonVideo(var FIGraphBuilder: IGraphBuilder; // var FICaptureGraphBuilder2: ICaptureGraphBuilder2; // var FSysDevEnum: IBaseFilter; // var FIVideoWindow: IVideoWindow; // var FIMediaControl: IMediaControl; // var FISampleGrabber: ISampleGrabber; // pv: PVideoInputInfo; pf: PVideoFormatInfo; // pnl: TPanel; // const strSaveFileName: string = ''; const bRecord: Boolean = False; // 录像 const bSnapBmp: Boolean = False // 截图 ): Boolean; var SampleGrabberFilter: IBaseFilter; mt : TAMMediaType; multiplexer : IBaseFilter; Writer : IFileSinkFilter; begin Result := False; { 创建 IGraphBuilder 接口 } if Failed(CocreateInstance(CLSID_FilterGraph, nil, CLSCTX_INPROC, IID_IGraphBuilder, FIGraphBuilder)) then Exit; { 创建 ICaptureGraphBuilder2 接口 } if Failed(CocreateInstance(CLSID_CaptureGraphBuilder2, nil, CLSCTX_INPROC, IID_ICaptureGraphBuilder2, FICaptureGraphBuilder2)) then Exit; { 调用 ICaptureGraphBuilder2 的 SetFilterGraph 方法将 FilterGraph 加入到Builder中 } if Failed(FICaptureGraphBuilder2.SetFiltergraph(FIGraphBuilder)) then Exit; { 获取指定USB摄像头的 Filter } FSysDevEnum := CreateFilter(CLSID_VideoInputDeviceCategory, AnsiString(pv^.strName), pv^.index); if FSysDevEnum = nil then Exit; { 设置指定 Filter 的媒体格式类型 } if not SetMediaType(FSysDevEnum, pf^.iWidth, pf^.iHeight, pf^.format) then Exit; { 将视频捕捉 Filter 添加到 Filter 图中 } if Failed(FIGraphBuilder.AddFilter(FSysDevEnum, 'VideoCapture')) then Exit; { 如果需要截图功能 } if bSnapBmp then begin CocreateInstance(CLSID_SampleGrabber, nil, CLSCTX_INPROC, IID_IBaseFilter, SampleGrabberFilter); FIGraphBuilder.AddFilter(SampleGrabberFilter, 'SampleGrabber'); SampleGrabberFilter.QueryInterface(IID_ISampleGrabber, FISampleGrabber); zeromemory(@mt, sizeof(AM_MEDIA_TYPE)); mt.majortype := MEDIATYPE_Video; mt.subtype := MEDIASUBTYPE_RGB24; // 24位，位图格式输出 FISampleGrabber.SetMediaType(@mt); // FISampleGrabber.SetBufferSamples(True); // 允许从 Buffer 中获取数据 { 渲染预览视频PIN } if Failed(FICaptureGraphBuilder2.RenderStream(@PIN_CATEGORY_PREVIEW, @MEDIATYPE_Video, FSysDevEnum, SampleGrabberFilter, nil)) then Exit; end else begin { 渲染预览视频PIN } if Failed(FICaptureGraphBuilder2.RenderStream(@PIN_CATEGORY_PREVIEW, @MEDIATYPE_Video, FSysDevEnum, nil, nil)) then Exit; end; { 如果是视频录制 } if bRecord then begin { 视频录制文件保持路径 } if Failed(FICaptureGraphBuilder2.SetOutputFileName(MEDIASUBTYPE_Avi, PWideChar(strSaveFileName), multiplexer, Writer)) then Exit; if Failed(FICaptureGraphBuilder2.RenderStream(@PIN_CATEGORY_CAPTURE, @MEDIATYPE_Video, FSysDevEnum, nil, multiplexer)) then Exit; end; { 设置视频预览窗口 } if Failed(FIGraphBuilder.QueryInterface(IID_IVideoWindow, FIVideoWindow)) then Exit; { 设置视频播放的WINDOWS窗口 } if Failed(FIVideoWindow.put_Owner(pnl.Handle)) then Exit; if Failed(FIVideoWindow.put_windowstyle(WS_CHILD or WS_Clipsiblings)) then Exit; { 设置视频尺寸 } if Failed(FIVideoWindow.SetWindowposition(0, 0, pnl.Width, pnl.Height)) then Exit; { 得到IMediaControl接口，用于控制流播放 } if Failed(FIGraphBuilder.QueryInterface(IID_IMediaControl, FIMediaControl)) then Exit; Result := True; end; { 视频预览 } function USBVideoPreview(var FIGraphBuilder: IGraphBuilder; var FICaptureGraphBuilder2: ICaptureGraphBuilder2; var FSysDevEnum: IBaseFilter; var FIVideoWindow: IVideoWindow; var FIMediaControl: IMediaControl; var FISampleGrabber: ISampleGrabber; pv: PVideoInputInfo; pf: PVideoFormatInfo; pnl: TPanel; const bSnapBmp: Boolean = False): Boolean; begin Result := CommonVideo(FIGraphBuilder, FICaptureGraphBuilder2, FSysDevEnum, FIVideoWindow, FIMediaControl, FISampleGrabber, pv, pf, pnl, '', False, True); end; { 视频录制 } function USBVideoRecord(var FIGraphBuilder: IGraphBuilder; var FICaptureGraphBuilder2: ICaptureGraphBuilder2; var FSysDevEnum: IBaseFilter; var FIVideoWindow: IVideoWindow; var FIMediaControl: IMediaControl; var FISampleGrabber: ISampleGrabber; pv: PVideoInputInfo; pf: PVideoFormatInfo; pnl: TPanel; const strSaveFileName: String): Boolean; begin Result := CommonVideo(FIGraphBuilder, FICaptureGraphBuilder2, FSysDevEnum, FIVideoWindow, FIMediaControl, FISampleGrabber, pv, pf, pnl, strSaveFileName, True, True); end; end.
好的代码像粥一样，都是用时间熬出来的
