avicap32.dll 动态加载

Question

    用了avicap32.dll用摄像头拍照，并保存图像，。但是我想把图像直接保存在内存流是不是调用这个静态方法capSetCallbackOnFrame,若是我不知道怎么调用并不知道它的参数.请各位高手帮忙啊，先谢谢了

Answer 1

LRESULT   CALLBACK   CCapture::VideoCallbackProc(HWND   hWnd,   LPVIDEOHDR   lpVHdr) 
{         if(   m_pStaticCap-> m_hwndParent   ) ::PostMessage(   m_pStaticCap-> m_hwndParent   ,   WM_CAPTUREONE   ,   (LPARAM)lpVHdr-> dwBufferLength   ,   (WPARAM)lpVHdr-> lpData   )   ;         return   (LRESULT)   TRUE   ; 
} 
/* 
//video   data   block   header   
typedef   struct   videohdr_tag   { 
        LPBYTE             lpData;                                   //pointer   to   locked   data   buffer   
        DWORD               dwBufferLength;                   //   Length   of   data   buffer   
        DWORD               dwBytesUsed;                         //   Bytes   actually   used   
        DWORD               dwTimeCaptured;                   //   Milliseconds   from   start   of   stream   
        DWORD               dwUser;                                   //   for   client 's   use   
        DWORD               dwFlags;                                 //   assorted   flags   (see   defines) 
        DWORD               dwReserved[4];                     //   reserved   for   driver 
}   VIDEOHDR,   NEAR   *PVIDEOHDR,   FAR   *   LPVIDEOHDR; 

Answer 2

http://www.cnblogs.com/oskycar/archive/2009/08/10/1543064.html

Answer 3

我学的C# 对于C++不太懂呀，能不能给个C#的例子呀

Answer 4

 private const int WM_USER = 0x400;
        private const int WS_CHILD = 0x40000000;
        private const int WS_VISIBLE = 0x10000000;
        private const int WM_CAP_START = WM_USER;
        private const int WM_CAP_STOP = WM_CAP_START + 68;
        private const int WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10;
        private const int WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11;
        private const int WM_CAP_SAVEDIB = WM_CAP_START + 25;
        private const int WM_CAP_GRAB_FRAME = WM_CAP_START + 60;
        private const int WM_CAP_SEQUENCE = WM_CAP_START + 62;
        private const int WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20;
        private const int WM_CAP_SEQUENCE_NOFILE = WM_CAP_START + 63;
        private const int WM_CAP_SET_OVERLAY = WM_CAP_START + 51;
        private const int WM_CAP_SET_PREVIEW = WM_CAP_START + 50;
        private const int WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START + 6;
        private const int WM_CAP_SET_CALLBACK_ERROR = WM_CAP_START + 2;
        private const int WM_CAP_SET_CALLBACK_STATUSA = WM_CAP_START + 3;
        private const int WM_CAP_SET_CALLBACK_FRAME = WM_CAP_START + 5;
        private const int WM_CAP_SET_SCALE = WM_CAP_START + 53;
        private const int WM_CAP_SET_PREVIEWRATE = WM_CAP_START + 52;
        private IntPtr hWndC;
        private bool bStat = false;
        private IntPtr mControlPtr;
        private int mWidth;
        private int mHeight;
        private int mLeft;
        private int mTop;
        ///
        /// 初始化摄像头
        ///
        /// 控件的句柄
        /// 开始显示的左边距
        /// 开始显示的上边距
        /// 要显示的宽度
        /// 要显示的长度
        public Pick(IntPtr handle, int left, int top, int width, int height)
        {
            mControlPtr = handle;
            mWidth = width;
            mHeight = height;
            mLeft = left;
            mTop = top;
        }
        [DllImport("avicap32.dll")]
        private static extern IntPtr capCreateCaptureWindowA(byte[] lpszWindowName, int dwStyle, int x, int y, int nWidth, int nHeight, IntPtr hWndParent, int nID);
        [DllImport("avicap32.dll")]
        private static extern int capGetVideoFormat(IntPtr hWnd, IntPtr psVideoFormat, int wSize);
        [DllImport("User32.dll")]
        private static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, int lParam);
        ///
        /// 开始显示图像
        ///
        public void Start()
        {
            if (bStat)
                return;
            bStat = true;
            byte[] lpszName = new byte[100];
            hWndC = capCreateCaptureWindowA(lpszName, WS_CHILD | WS_VISIBLE, mLeft, mTop, mWidth, mHeight, mControlPtr, 0);
            if (hWndC.ToInt32() != 0)
            {
                SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0);
                SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0);
                SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0);
                SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0);
                SendMessage(hWndC, WM_CAP_SET_SCALE, 1, 0);
                SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0);
                SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0);
                SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0);
            }
            return;
        }
        ///
        /// 停止显示
        ///
        public void Stop()
        {
            SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
            bStat = false;
        }
        ///
        /// 抓图
        ///
        /// 要保存bmp文件的路径
        public void GrabImage(string path)
         //public void GrabImage( )
        {
            IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);
            SendMessage(hWndC, WM_CAP_SAVEDIB, 0, hBmp.ToInt32());
        }

Answer 5

谢谢你，我不是想把它保存到文件中而是保存到内存Bitmap流中还要时时的更改不要每次都要读取文件

Answer 6

//假设你已经可以拿到位图,那么你可以存到MemoryStream
Bitmap bm = new Bitmap(width,Height);
MemoryStream ms = new MemoryStream();
bm.Save(ms, ImageFormat.Png);

Answer 7

这位大侠我要的图片不是从文件中读取的，而是在Aivcap32.dll动态扫描得到的呀，且是时时改变的相当于是时时捕获视频帧

Answer 8

我也一直想知道这个问题，可就是没有一人知道。我不要把照片数据放在剪切板上，因为这样，一秒才二张内存Bitmap流，太慢了