视频捕捉程序开发的基本步骤

视频捕捉程序开发的基本步骤 2 视频捕捉程序开发的基本步骤 2.1 使用AVICap窗口类 笔者使用的是AVICap窗口类来开发视频捕捉程序。AVICap类支持实时视频流捕捉和单帧捕捉，并提供对视频源的控制。通常使用的MCI控件虽然也提供了数字视频服务。并为视频叠加提供了Overlay命令集等，但这些命令主要是基于文件的操作，还不能满足实时地从视频缓存中提取数据的要求。对于使用没有视频叠加能力的捕捉卡的PC机来说，用MCI提供的命令集是无法捕捉视频流的。而AVICap窗口类在捕捉视频方面具有一定的优势，它能直接访问视频缓冲区，而不需要生成中间文件，因而实时性很强，效率也很高。另外，它还可将数字视频捕捉到一个文件中。 2.2 开发的基本步骤 开发视频捕捉程序主要有以下四个步骤: (1)创建“捕捉窗”。 在进行视频捕捉之前必需要先创建一个“捕捉窗”，并应以此为基础进行所有的捕捉及设置操作。“捕捉窗”可用AVICap窗口类的“Cap Create Capture Window”函数来创建， 其窗口风格可设置为WSCHILD和WS_VISIBLE参数。 “捕捉窗”类似于控件，它具有下列功能: 将视频流和音频流捕捉到一个AVI文件中; 动态地同视频和音频输入器件连接或断开; 以Overlay或Preview模式对输入的视频流进行实时显示; 在捕捉时，可指定所用的文件名，并可将捕捉文件的内容拷贝到另一个文件; 设置捕捉速率; 显示控制视频源、视频格式及视频压缩的对话框; 创建、保存或载入调色板; 将图像和相关的调色板拷贝到剪贴板; 将捕捉的单帧图像保存到DIB格式文件。 (2)关联捕捉窗和驱动程序 单独定义的捕捉窗是不能工作的，它须与一个设备相关联才能取得视频信号。用函数CapDriver Connect可使捕捉窗与其设备驱动程序相关联。 (3)设置视频设备的属性 通过设置TcaptureParms结构变量的各个成员变量，可以控制设备的采样频率、中断采样按键、状态行为。设置好TcaptureParms结构变量后，可以用函CapCaptureSetSetup 使设置生效。之后还可以用CapPreviewScale、CapPreviewRate设置预览的比例与速度，也可以直接使用设备的默认值。 (4)打开预览 利用函数CapOverlay可选择是否采用叠加模式预览，以使系统资源占用小，视频显示速度加快。然后用CapPreview启动预览功能，这时就可以在屏幕上看到来自摄像机的图像了。 通过以上四步就可以建立一个基本的视频捕捉程序，但假如想自己处理从设备捕捉到的视频数据，则要使用捕捉窗回调函数来处理，比如一帧一帧地获得视频数据或以流的方式获得视频数据等。 3 基于Delphi的视频捕捉程序 根据系统对系统访问、处理速度等方面的非凡需求，笔者选用Delphi作为开发工具。下面以开发一个逐帧从视频设备上捕捉视频数据的程序为例，来说明每个函数的作用以及开发的具体过程。所给例程的功能是可以在屏幕上显示捕捉到的视频，并可以获得每一帧的图像数据。具体步骤如下: (1)新建一个，并将AVICAP32.PAS包含到USES中。 {PASCAL INTERFACE for AVICAP32 DLL} {Converted from microsoft Header file by ArTee} {Free to use - I'm NOT responsible fo bugs} unit avicap32; interface uses Windows, Messages, SysUtils, MMSystem; //This part might be buggy. //It 'Assumes' types because I cannot find the correct unit type HVIDEO = longword; //Handle; UINT = longword; POINT = record x, y: integer end; LPPOINT = ^POINT; FOURCC = record c1, c2, c3, c4: char; end; mmioFOURCC = FOURCC; LPVOID = Pointer; //LPWAVEHDR, LPVIDEOHDR worden gebruikt in de call-back functions! ik heb ze maar gereplaced met integers. {*************************************************************************** * * avicap.h * * Main include file. * * Microsoft Video for Windows Sample Capture Class * * Copyright (c) 1992, 1993 Microsoft Corporation. All Rights Reserved. * * You have a royalty-free right to use, modify, reproduce and * distribute the Sample Files (and/or any modified version) in * any way you find useful, provided that you agree that * Microsoft has no warranty obligations or liability for any * Sample Application Files which are modified. * **************************************************************************} //const AVICapSM =SendMessage; { SendMessage in C } // ------------------------------------------------------------------ // Window Messages WM_CAP... which can be sent to an AVICAP window // ------------------------------------------------------------------ // Defines start of the message range const WM_CAP_START = WM_USER; const WM_CAP_GET_CAPSTREAMPTR = (WM_CAP_START + 1); const WM_CAP_SET_CALLBACK_ERROR = (WM_CAP_START + 2); const WM_CAP_SET_CALLBACK_STATUS = (WM_CAP_START + 3); const WM_CAP_SET_CALLBACK_YIELD = (WM_CAP_START + 4); const WM_CAP_SET_CALLBACK_FRAME = (WM_CAP_START + 5); const WM_CAP_SET_CALLBACK_VIDEOSTREAM = (WM_CAP_START + 6); const WM_CAP_SET_CALLBACK_WAVESTREAM = (WM_CAP_START + 7); const WM_CAP_GET_USER_DATA = (WM_CAP_START + 8); const WM_CAP_SET_USER_DATA = (WM_CAP_START + 9); const WM_CAP_DRIVER_CONNECT = (WM_CAP_START + 10); const WM_CAP_DRIVER_DISCONNECT = (WM_CAP_START + 11); const WM_CAP_DRIVER_GET_NAME = (WM_CAP_START + 12); const WM_CAP_DRIVER_GET_VERSION = (WM_CAP_START + 13); const WM_CAP_DRIVER_GET_CAPS = (WM_CAP_START + 14); const WM_CAP_FILE_SET_CAPTURE_FILE = (WM_CAP_START + 20); const WM_CAP_FILE_GET_CAPTURE_FILE = (WM_CAP_START + 21); const WM_CAP_FILE_ALLOCATE = (WM_CAP_START + 22); const WM_CAP_FILE_SAVEAS = (WM_CAP_START + 23); const WM_CAP_FILE_SET_INFOCHUNK = (WM_CAP_START + 24); const WM_CAP_FILE_SAVEDIB = (WM_CAP_START + 25); const WM_CAP_EDIT_COPY = (WM_CAP_START + 30); const WM_CAP_SET_AUDIOFORMAT = (WM_CAP_START + 35); const WM_CAP_GET_AUDIOFORMAT = (WM_CAP_START + 36); const WM_CAP_DLG_VIDEOFORMAT = (WM_CAP_START + 41); const WM_CAP_DLG_VIDEOSOURCE = (WM_CAP_START + 42); const WM_CAP_DLG_VIDEODISPLAY = (WM_CAP_START + 43); const WM_CAP_GET_VIDEOFORMAT = (WM_CAP_START + 44); const WM_CAP_SET_VIDEOFORMAT = (WM_CAP_START + 45); const WM_CAP_DLG_VIDEOCOMPRESSION = (WM_CAP_START + 46); const WM_CAP_SET_PREVIEW = (WM_CAP_START + 50); const WM_CAP_SET_OVERLAY = (WM_CAP_START + 51); const WM_CAP_SET_PREVIEWRATE = (WM_CAP_START + 52); const WM_CAP_SET_SCALE = (WM_CAP_START + 53); const WM_CAP_GET_STATUS = (WM_CAP_START + 54); const WM_CAP_SET_SCROLL = (WM_CAP_START + 55); const WM_CAP_GRAB_FRAME = (WM_CAP_START + 60); const WM_CAP_GRAB_FRAME_NOSTOP = (WM_CAP_START + 61); const WM_CAP_SEQUENCE = (WM_CAP_START + 62); const WM_CAP_SEQUENCE_NOFILE = (WM_CAP_START + 63); const WM_CAP_SET_SEQUENCE_SETUP = (WM_CAP_START + 64); const WM_CAP_GET_SEQUENCE_SETUP = (WM_CAP_START + 65); const WM_CAP_SET_MCI_DEVICE = (WM_CAP_START + 66); const WM_CAP_GET_MCI_DEVICE = (WM_CAP_START + 67); const WM_CAP_STOP = (WM_CAP_START + 68); const WM_CAP_ABORT = (WM_CAP_START + 69); const WM_CAP_SINGLE_FRAME_OPEN = (WM_CAP_START + 70); const WM_CAP_SINGLE_FRAME_CLOSE = (WM_CAP_START + 71); const WM_CAP_SINGLE_FRAME = (WM_CAP_START + 72); const WM_CAP_PAL_OPEN = (WM_CAP_START + 80); const WM_CAP_PAL_SAVE = (WM_CAP_START + 81); const WM_CAP_PAL_PASTE = (WM_CAP_START + 82); const WM_CAP_PAL_AUTOCREATE = (WM_CAP_START + 83); const WM_CAP_PAL_MANUALCREATE = (WM_CAP_START + 84); // Following added post VFW 1.1 const WM_CAP_SET_CALLBACK_CAPCONTROL = (WM_CAP_START + 85); // Defines end of the message range const WM_CAP_END = WM_CAP_SET_CALLBACK_CAPCONTROL; // ------------------------------------------------------------------ // structures // ------------------------------------------------------------------ type tagCapDriverCaps = packed record wDeviceIndex: word; // Driver index in system.ini fHasOverlay: wordbool; // Can device overlay? fHasDlgVideoSource: wordbool; // Has Video source dlg? fHasDlgVideoFormat: wordbool; // Has Format dlg? fHasDlgVideoDisplay: wordbool; // Has External out dlg? fCaptureInitialized: wordbool; // Driver ready to capture? fDriverSuppliesPalettes: wordbool; // Can driver make palettes? hVideoIn: HVIDEO; // Driver In channel hVideoOut: HVIDEO; // Driver Out channel hVideoExtIn: HVIDEO; // Driver Ext In channel hVideoExtOut: HVIDEO; // Driver Ext Out channel end; CAPDRIVERCAPS = tagCapDriverCaps; PCAPDRIVERCAPS = ^tagCapDriverCaps; LPCAPDRIVERCAPS = ^tagCapDriverCaps; type tagCapStatus = record uiImageWidth: UInt; // Width of the image uiImageHeight: UInt; // Height of the image fLiveWindow: longbool; // Now Previewing video? fOverlayWindow: longbool; // Now Overlaying video? fScale: longbool; // Scale image to client? ptScroll: POINT; // Scroll position fUsingDefaultPalette: longbool; // Using default driver palette? fAudioHardware: longbool; // Audio hardware present? fCapFileExists: longbool; // Does capture file exist? dwCurrentVideoFrame: DWORD; // # of video frames cap'td dwCurrentVideoFramesDropped: DWORD; // # of video frames dropped dwCurrentWaveSamples: DWORD; // # of wave samples cap'td dwCurrentTimeElapsedMS: DWORD; // Elapsed capture duration hPalCurrent: HPALETTE;// Current palette in use fCapturingNow: longbool; // Capture in progress? dwReturn: DWORD; // Error value after any operation wNumVideoAllocated: word; // Actual number of video buffers wNumAudioAllocated: word; // Actual number of audio buffers end; CAPSTATUS = tagCapStatus; PCAPSTATUS = ^tagCapStatus; LPCAPSTATUS = ^tagCapStatus; // Default values in parenthesis type tagCaptureParms = record dwRequestMicroSecPerFrame: DWORD; // Requested capture rate fMakeUserHitOKToCapture: longbool; // Show "Hit OK to cap" dlg? wPercentDropForError: word; // Give error msg if > (10%) fYield: longbool; // Capture via background task? dwIndexSize: DWORD; // Max index size in frames (32K) wChunkGranularity: word; // Junk chunk granularity (2K) fUsingDOSMemory: longbool; // Use DOS buffers? wNumVideoRequested: word; // # video buffers, If 0, autocalc fCaptureAudio: longbool; // Capture audio? wNumAudioRequested: word; // # audio buffers, If 0, autocalc vKeyAbort: word; // Virtual key causing abort fAbortLeftMouse: longbool; // Abort on left mouse? fAbortRightMouse: longbool; // Abort on right mouse? fLimitEnabled: longbool; // Use wTimeLimit? wTimeLimit: word; // Seconds to capture fMCIControl: longbool; // Use MCI video source? fStepMCIDevice: longbool; // Step MCI device? dwMCIStartTime: DWORD; // Time to start in MS dwMCIStopTime: DWORD; // Time to stop in MS fStepCaptureAt2x: longbool; // Perform spatial averaging 2x wStepCaptureAverageFrames: word; // Temporal average n Frames dwAudioBufferSize: DWORD; // Size of audio bufs (0 : default) fDisableWriteCache: longbool; // Attempt to disable write cache end; CAPTUREPARMS = tagCaptureParms; PCAPTUREPARMS = ^tagCaptureParms; LPCAPTUREPARMS = ^tagCaptureParms; type tagCapInfoChunk = record fccInfoID: FOURCC; // Chunk ID, "ICOP" for copyright lpData: LPVOID; // poSmallInter to data cbData: integer; // size of lpData end; CAPINFOCHUNK = tagCapInfoChunk; PCAPINFOCHUNK = ^tagCapInfoChunk; LPCAPINFOCHUNK = ^tagCapInfoChunk; //Type TVideoHDR is not present in avicap32.. we might need it so we add it type TVideoHDR = record lpData: Pointer {LPBYTE}; //* pointer to locked data buffer */ dwBufferLength: DWord; //* Length of data buffer */ dwBytesUsed: DWord; //* Bytes actually used */ dwTimeCaptured: DWord; //* Milliseconds from startof stream */ dwUser: DWord; //* for client's use */ dwFlags: DWord; // assorted flags(see defines)*/ dwReserved{[4]}: DWord; //* reserved for driver */ end; PVideoHDR = ^TVideoHDR; LPVideoHDR = PVideoHDR; //* dwFlags field of VIDEOHDR */ const VHDR_DONE = $00000001; //* Done bit */ const VHDR_PREPARED = $00000002; //* Set if this header has been prepared */ const VHDR_INQUEUE = $00000004; //* Reserved for driver */ const VHDR_KEYFRAME = $00000008; //* Key Frame */ // ------------------------------------------------------------------ // Callback Definitions // ------------------------------------------------------------------ //Nog zo'n mooi stukkie dat ik ff laat zitten. // componentje van maken, zelf de callback doen. type CAPYIELDCALLBACK = function(hWnd: HWND): LRESULT; stdcall; type CAPSTATUSCALLBACK = function(hWnd: HWND; nID: smallint; lpsz: LPCSTR): LRESULT; stdcall; type CAPERRORCALLBACK = function(hWnd: HWND; nID: smallint; lpsz: LPCSTR): LRESULT; stdcall; type CAPVIDEOCALLBACK = function(hWnd: HWND; lpVHdr: integer{LPVIDEOHDR}): LRESULT; stdcall; type CAPWAVECALLBACK = function(hWnd: HWND; lpWHdr: integer{LPWAVEHDR}): LRESULT; stdcall; type CAPCONTROLCALLBACK = function(hWnd: HWND; nState: smallint): LRESULT; stdcall; // ------------------------------------------------------------------ // CapControlCallback states // ------------------------------------------------------------------ const CONTROLCALLBACK_PREROLL = 1; { Waiting to start capture } const CONTROLCALLBACK_CAPTURING = 2; { Now capturing } // ------------------------------------------------------------------ // The only exported functions from AVICAP.DLL // ------------------------------------------------------------------ function {VFWAPI} capCreateCaptureWindow(lpszWindowName: LPCSTR; dwStyle: DWORD; x, y, nWidth, nHeight: integer; hwndParent: HWND; nID: integer): HWND; stdcall; external 'AVICAP32.DLL' Name 'capCreateCaptureWindowA'; function {VFWAPI} capGetDriverDescription(wDriverIndex: word; lpszName: LPSTR; cbName: integer; lpszVer: LPSTR; cbVer: integer): longbool; stdcall; external 'AVICAP32.DLL' Name 'capGetDriverDescriptionA'; // ------------------------------------------------------------------ // New Information chunk IDs // ------------------------------------------------------------------ const infotypeDIGITIZATION_TIME = ('IDIT'); const infotypeSMPTE_TIME = ('ISMP'); // ------------------------------------------------------------------ // String IDs from status and error callbacks // ------------------------------------------------------------------ const IDS_CAP_BEGIN = 300; { "Capture Start" } const IDS_CAP_END = 301; { "Capture End" } const IDS_CAP_INFO = 401; { "%s" } const IDS_CAP_OUTOFMEM = 402; { "Out of memory" } const IDS_CAP_FILEEXISTS = 403; { "File '%s' exists -- overwrite it?" } const IDS_CAP_ERRORPALOPEN = 404; { "Error opening palette '%s'" } const IDS_CAP_ERRORPALSAVE = 405; { "Error saving palette '%s'" } const IDS_CAP_ERRORDIBSAVE = 406; { "Error saving frame '%s'" } const IDS_CAP_DEFAVIEXT = 407; { "avi" } const IDS_CAP_DEFPALEXT = 408; { "pal" } const IDS_CAP_CANTOPEN = 409; { "Cannot open '%s'" } const IDS_CAP_SEQ_MSGSTART = 410; { "Select OK to start capture\nof video sequence\nto %s." } const IDS_CAP_SEQ_MSGSTOP = 411; { "Hit ESCAPE or click to end capture" } const IDS_CAP_VIDEDITERR = 412; { "An error occurred while trying to run VidEdit." } const IDS_CAP_READONLYFILE = 413; { "The file '%s' is a read-only file." } const IDS_CAP_WRITEERROR = 414; { "Unable to write to file '%s'.\nDisk may be full." } const IDS_CAP_NODISKSPACE = 415; { "There is no space to create a capture file on the specified device." } const IDS_CAP_SETFILESIZE = 416; { "Set File Size" } const IDS_CAP_SAVEASPERCENT = 417; { "SaveAs: %2ld%% Hit Escape to abort." } const IDS_CAP_DRIVER_ERROR = 418; { Driver specific error message } const IDS_CAP_WAVE_OPEN_ERROR = 419; { "Error: Cannot open the wave input device.\nCheck sample size, frequency, and channels." } const IDS_CAP_WAVE_ALLOC_ERROR = 420; { "Error: Out of memory for wave buffers." } const IDS_CAP_WAVE_PREPARE_ERROR = 421; { "Error: Cannot prepare wave buffers." } const IDS_CAP_WAVE_ADD_ERROR = 422; { "Error: Cannot add wave buffers." } const IDS_CAP_WAVE_SIZE_ERROR = 423; { "Error: Bad wave size." } const IDS_CAP_VIDEO_OPEN_ERROR = 424; { "Error: Cannot open the video input device." } const IDS_CAP_VIDEO_ALLOC_ERROR = 425; { "Error: Out of memory for video buffers." } const IDS_CAP_VIDEO_PREPARE_ERROR = 426; { "Error: Cannot prepare video buffers." } const IDS_CAP_VIDEO_ADD_ERROR = 427; { "Error: Cannot add video buffers." } const IDS_CAP_VIDEO_SIZE_ERROR = 428; { "Error: Bad video size." } const IDS_CAP_FILE_OPEN_ERROR = 429; { "Error: Cannot open capture file." } const IDS_CAP_FILE_WRITE_ERROR = 430; { "Error: Cannot write to capture file. Disk may be full." } const IDS_CAP_RECORDING_ERROR = 431; { "Error: Cannot write to capture file. Data rate too high or disk full." } const IDS_CAP_RECORDING_ERROR2 = 432; { "Error while recording" } const IDS_CAP_AVI_INIT_ERROR = 433; { "Error: Unable to initialize for capture." } const IDS_CAP_NO_FRAME_CAP_ERROR = 434; { "Warning: No frames captured.\nConfirm that vertical sync SmallInterrupts\nare configured and enabled." } const IDS_CAP_NO_PALETTE_WARN = 435; { "Warning: Using default palette." } const IDS_CAP_MCI_CONTROL_ERROR = 436; { "Error: Unable to access MCI device." } const IDS_CAP_MCI_CANT_STEP_ERROR = 437; { "Error: Unable to step MCI device." } const IDS_CAP_NO_AUDIO_CAP_ERROR = 438; { "Error: No audio data captured.\nCheck audio card settings." } const IDS_CAP_AVI_DRAWDIB_ERROR = 439; { "Error: Unable to draw this data format." } const IDS_CAP_COMPRESSOR_ERROR = 440; { "Error: Unable to initialize compressor." } const IDS_CAP_AUDIO_DROP_ERROR = 441; { "Error: Audio data was lost during capture, reduce capture rate." } { status string IDs } const IDS_CAP_STAT_LIVE_MODE = 500; { "Live window" } const IDS_CAP_STAT_OVERLAY_MODE = 501; { "Overlay window" } const IDS_CAP_STAT_CAP_INIT = 502; { "Setting up for capture - Please wait" } const IDS_CAP_STAT_CAP_FINI = 503; { "Finished capture, now writing frame %ld" } const IDS_CAP_STAT_PALETTE_BUILD = 504; { "Building palette map" } const IDS_CAP_STAT_OPTPAL_BUILD = 505; { "Computing optimal palette" } const IDS_CAP_STAT_I_FRAMES = 506; { "%d frames" } const IDS_CAP_STAT_L_FRAMES = 507; { "%ld frames" } const IDS_CAP_STAT_CAP_L_FRAMES = 508; { "Captured %ld frames" } const IDS_CAP_STAT_CAP_AUDIO = 509; { "Capturing audio" } const IDS_CAP_STAT_VIDEOCURRENT = 510; { "Captured %ld frames (%ld dropped) %d.%03d sec." } const IDS_CAP_STAT_VIDEOAUDIO = 511; { "Captured %d.%03d sec. %ld frames (%ld dropped) (%d.%03d fps). %ld audio bytes (%d,%03d sps)" } const IDS_CAP_STAT_VIDEOONLY = 512; { "Captured %d.%03d sec. %ld frames (%ld dropped) (%d.%03d fps)" } const IDS_CAP_STAT_FRAMESDROPPED = 513; { "Dropped %ld of %ld frames (%d.%02d%%) during capture." } function capSetCallbackOnStatus(Handle: HWND; fpProc: Pointer): integer; function capSetCallbackOnYield(Handle: HWND; fpProc: Pointer): integer; function capSetCallbackOnFrame(Handle: HWND; fpProc: Pointer): integer; function capSetCallbackOnVideoStream(Handle: HWND; fpProc: Pointer): integer; function capSetCallbackOnWaveStream(Handle: HWND; fpProc: Pointer): integer; function capSetCallbackOnCapControl(Handle: HWND; fpProc: Pointer): integer; function capSetUserData(Handle: HWND; lUser: integer): integer; function capGetUserData(Handle: HWND): integer; function capDriverConnect(Handle: HWND; i: integer): integer; function capDriverDisconnect(Handle: HWND): integer; function capDriverGetName(Handle: HWND; szName: PChar; wSize: integer): integer; function capDriverGetVersion(Handle: HWND; szVer: integer; wSize: integer): integer; function capDriverGetCaps(Handle: HWND; s: LPCapDriverCaps; wSize: integer): integer; function capFileSetCaptureFile(Handle: HWND; szName: PChar): integer; function capFileGetCaptureFile(Handle: HWND; szName: PChar; wSize: integer): integer; function capFileAlloc(Handle: HWND; dwSize: integer): integer; function capFileSaveAs(Handle: HWND; szName: PChar): integer; function capFileSetInfoChunk(Handle: HWND; lpInfoChunk: LPCapInfoChunk): integer; function capFileSaveDIB(Handle: HWND; szName: PChar): integer; function capEditCopy(Handle: HWND): integer; function capSetAudioFormat(Handle: HWND; s: PWaveFormatEx; wSize: integer): integer; function capGetAudioFormat(Handle: HWND; s: PWaveFormatEx; wSize: integer): DWord; function capGetAudioFormatSize(Handle: HWND): DWord; function capDlgVideoFormat(Handle: HWND): integer; function capDlgVideoSource(Handle: HWND): integer; function capDlgVideoDisplay(Handle: HWND): integer; function capDlgVideoCompression(Handle: HWND): integer; function capGetVideoFormat(Handle: HWND; s: integer; wSize: integer): DWord; function capGetVideoFormatSize(Handle: HWND): DWord; function capSetVideoFormat(Handle: HWND; s: integer; wSize: integer): integer; function capPreview(Handle: HWND; f: longbool): integer; function capPreviewRate(Handle: HWND; wMS: integer): integer; function capOverlay(Handle: HWND; f: longbool): integer; function capPreviewScale(Handle: HWND; f: longbool): integer; function capGetStatus(Handle: HWND; s: LPCapStatus; wSize: integer): integer; function capSetScrollPos(Handle: HWND; lpP: LPPOINT): integer; function capGrabFrame(Handle: HWND): integer; function capGrabFrameNoStop(Handle: HWND): integer; function capCaptureSequence(Handle: HWND): integer; function capCaptureSequenceNoFile(Handle: HWND): integer; function capCaptureStop(Handle: HWND): integer; function capCaptureAbort(Handle: HWND): integer; function capCaptureSingleFrameOpen(Handle: HWND): integer; function capCaptureSingleFrameClose(Handle: HWND): integer; function capCaptureSingleFrame(Handle: HWND): integer; function capCaptureGetSetup(Handle: HWND; s: LPCaptureParms; wSize: integer): integer; function capCaptureSetSetup(Handle: HWND; s: LPCaptureParms; wSize: integer): integer; function capSetMCIDeviceName(Handle: HWND; szName: PChar): integer; function capGetMCIDeviceName(Handle: HWND; szName: PChar; wSize: integer): longbool; function capPaletteOpen(Handle: HWND; szName: PChar): integer; function capPaletteSave(Handle: HWND; szName: PChar): integer; function capPalettePaste(Handle: HWND): integer; function capPaletteAuto(Handle: HWND; iFrames: integer; iColors: integer): integer; function capPaletteManual(Handle: HWND; fGrab: integer; iColors: integer): integer; implementation // ------------------------------------------------------------------ // Message crackers for above // ------------------------------------------------------------------ //Leuk, maar dat moet dan richting implemenation... function capSetCallbackOnError(hwnd: integer; fpProc: Pointer): integer; begin Result := sendmessage(hwnd, WM_CAP_SET_CALLBACK_ERROR, 0, integer(fpProc)); end; function capSetCallbackOnStatus(Handle: HWND; fpProc: Pointer): integer; begin Result := sendmessage(handle, WM_CAP_SET_CALLBACK_STATUS, 0, integer(fpProc)); end; function capSetCallbackOnYield(Handle: HWND; fpProc: Pointer): integer; begin Result := sendmessage(handle, WM_CAP_SET_CALLBACK_YIELD, 0, integer(fpProc)); end; function capSetCallbackOnFrame(Handle: HWND; fpProc: Pointer): integer; begin Result := sendmessage(handle, WM_CAP_SET_CALLBACK_FRAME, 0, integer(fpProc)); end; function capSetCallbackOnVideoStream(Handle: HWND; fpProc: Pointer): integer; begin Result := sendmessage(handle, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, integer(fpProc)); end; function capSetCallbackOnWaveStream(Handle: HWND; fpProc: Pointer): integer; begin Result := sendmessage(handle, WM_CAP_SET_CALLBACK_WAVESTREAM, 0, integer(fpProc)); end; function capSetCallbackOnCapControl(Handle: HWND; fpProc: Pointer): integer; begin Result := sendmessage(handle, WM_CAP_SET_CALLBACK_CAPCONTROL, 0, integer(fpProc)); end; function capSetUserData(Handle: HWND; lUser: integer): integer; begin Result := sendmessage(handle, WM_CAP_SET_USER_DATA, 0, lUser); end; function capGetUserData(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_GET_USER_DATA, 0, 0); end; function capDriverConnect(Handle: HWND; i: integer): integer; begin Result := sendmessage(handle, WM_CAP_DRIVER_CONNECT, i, 0); end; function capDriverDisconnect(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_DRIVER_DISCONNECT, 0, 0); end; function capDriverGetName(Handle: HWND; szName: PChar; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_DRIVER_GET_NAME, (wSize), integer(szName)); end; function capDriverGetVersion(Handle: HWND; szVer: integer; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_DRIVER_GET_VERSION, (wSize), (szVer)); end; function capDriverGetCaps(Handle: HWND; s: LPCapDriverCaps; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_DRIVER_GET_CAPS, (wSize), integer(s)); end; function capFileSetCaptureFile(Handle: HWND; szName: PChar): integer; begin Result := sendmessage(handle, WM_CAP_FILE_SET_CAPTURE_FILE, 0, integer(szName)); end; function capFileGetCaptureFile(Handle: HWND; szName: PChar; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_FILE_GET_CAPTURE_FILE, (wSize), integer(szName)); end; function capFileAlloc(Handle: HWND; dwSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_FILE_ALLOCATE, 0, (dwSize)); end; function capFileSaveAs(Handle: HWND; szName: PChar): integer; begin Result := sendmessage(handle, WM_CAP_FILE_SAVEAS, 0, integer(szName)); end; function capFileSetInfoChunk(Handle: HWND; lpInfoChunk: LPCapInfoChunk): integer; begin Result := sendmessage(handle, WM_CAP_FILE_SET_INFOCHUNK, 0, integer(lpInfoChunk)); end; function capFileSaveDIB(Handle: HWND; szName: PChar): integer; begin Result := sendmessage(handle, WM_CAP_FILE_SAVEDIB, 0, integer(szName)); end; function capEditCopy(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_EDIT_COPY, 0, 0); end; function capSetAudioFormat(Handle: HWND; s: PWaveFormatEx; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_SET_AUDIOFORMAT, (wSize), integer(s)); end; function capGetAudioFormat(Handle: HWND; s: PWaveFormatEx; wSize: integer): DWord; begin Result := sendmessage(handle, WM_CAP_GET_AUDIOFORMAT, (wSize), integer(s)); end; function capGetAudioFormatSize(Handle: HWND): DWord; begin Result := sendmessage(handle, WM_CAP_GET_AUDIOFORMAT, 0, 0{ NULL}); end; function capDlgVideoFormat(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_DLG_VIDEOFORMAT, 0, 0); end; function capDlgVideoSource(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_DLG_VIDEOSOURCE, 0, 0); end; function capDlgVideoDisplay(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_DLG_VIDEODISPLAY, 0, 0); end; function capDlgVideoCompression(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_DLG_VIDEOCOMPRESSION, 0, 0); end; function capGetVideoFormat(Handle: HWND; s: integer; wSize: integer): DWord; begin Result := sendmessage(handle, WM_CAP_GET_VIDEOFORMAT, (wSize), (s)); end; function capGetVideoFormatSize(Handle: HWND): DWord; begin Result := DWORD(sendmessage(handle, WM_CAP_GET_VIDEOFORMAT, 0, 0)); end; function capSetVideoFormat(Handle: HWND; s: integer; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_SET_VIDEOFORMAT, (wSize), (s)); end; function capPreview(Handle: HWND; f: longbool): integer; begin Result := sendmessage(handle, WM_CAP_SET_PREVIEW, integer(f), 0); end; function capPreviewRate(Handle: HWND; wMS: integer): integer; begin Result := sendmessage(handle, WM_CAP_SET_PREVIEWRATE, (wMS), 0); end; function capOverlay(Handle: HWND; f: longbool): integer; begin Result := sendmessage(handle, WM_CAP_SET_OVERLAY, integer(f), 0); end; function capPreviewScale(Handle: HWND; f: longbool): integer; begin Result := sendmessage(handle, WM_CAP_SET_SCALE, integer(f), 0); end; function capGetStatus(Handle: HWND; s: LPCapStatus; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_GET_STATUS, wSize, integer(s)); end; function capSetScrollPos(Handle: HWND; lpP: LPPOINT): integer; begin Result := sendmessage(handle, WM_CAP_SET_SCROLL, 0, integer(lpP)); end; function capGrabFrame(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_GRAB_FRAME, 0, 0); end; function capGrabFrameNoStop(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_GRAB_FRAME_NOSTOP, 0, 0); end; function capCaptureSequence(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_SEQUENCE, 0, 0); end; function capCaptureSequenceNoFile(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_SEQUENCE_NOFILE, 0, 0); end; function capCaptureStop(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_STOP, 0, 0); end; function capCaptureAbort(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_ABORT, 0, 0); end; function capCaptureSingleFrameOpen(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_SINGLE_FRAME_OPEN, 0, 0); end; function capCaptureSingleFrameClose(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_SINGLE_FRAME_CLOSE, 0, 0); end; function capCaptureSingleFrame(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_SINGLE_FRAME, 0, 0); end; function capCaptureGetSetup(Handle: HWND; s: LPCaptureParms; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_GET_SEQUENCE_SETUP, (wSize), integer(s)); end; function capCaptureSetSetup(Handle: HWND; s: LPCaptureParms; wSize: integer): integer; begin Result := sendmessage(handle, WM_CAP_SET_SEQUENCE_SETUP, (wSize), integer(s)); end; function capSetMCIDeviceName(Handle: HWND; szName: PChar): integer; begin Result := sendmessage(handle, WM_CAP_SET_MCI_DEVICE, 0, integer(szName)); end; function capGetMCIDeviceName(Handle: HWND; szName: PChar; wSize: integer): longbool; begin Result := longbool(sendmessage(handle, WM_CAP_GET_MCI_DEVICE, (wSize), integer(szName))); end; function capPaletteOpen(Handle: HWND; szName: PChar): integer; begin Result := sendmessage(handle, WM_CAP_PAL_OPEN, 0, integer(szName)); end; function capPaletteSave(Handle: HWND; szName: PChar): integer; begin Result := sendmessage(handle, WM_CAP_PAL_SAVE, 0, integer(szName)); end; function capPalettePaste(Handle: HWND): integer; begin Result := sendmessage(handle, WM_CAP_PAL_PASTE, 0, 0); end; function capPaletteAuto(Handle: HWND; iFrames: integer; iColors: integer): integer; begin Result := sendmessage(handle, WM_CAP_PAL_AUTOCREATE, (iFrames), (iColors)); end; function capPaletteManual(Handle: HWND; fGrab: integer; iColors: integer): integer; begin Result := sendmessage(handle, WM_CAP_PAL_MANUALCREATE, (fGrab), (iColors)); end; end. (2)在Form1上放置一个Tpanel控件，设Name为“gCapVideoArea”，该控件用于 显示视频。之后再放置两个Tbutton控件，一个Name为“Openvideo”，另一个Name为 “Closevideo”。 (3)定义全局变量 ghCapWnd:Thandle; //定义捕捉窗句柄 VideoStr:LPVIDEOHDR; //可以得到视频数据指针的结构变量，用于回调函数中 CapParms:TcaptureParms; //用于设置设备属性的结构变量 (4)编写代码 在Name为“Openvideo”的Tbutton的Click事件中写入以下代码: procedure Tform1.OpenvidoClick; begin //使用Tpanel控件来创建捕捉窗口 ghCapWnd:,CapCreateCaptureWindow， WS_CHILD or WS_VISIBLE， //窗口样式 0，//X坐标 0，//Y坐标 gCapVideoArea，Width， //窗口宽 gCapVideoArea，Handle， //窗口句柄 0); //一般为0 为了能够捕捉视频，应启动一个捕捉帧回调函数VideoStreamC