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avicap32.dll操作摄像头失败 RRS feed

  • 问题

  • 我使用avicap32.dll来操作摄像头,按照网上所说的方法,就是适中没有结果,请高手帮忙指点一下

    首先是pick摄像头操作类

    using System.Runtime.InteropServices;
    using System.Drawing;
    using System.Drawing.Imaging;
    using System;

    namespace Camera
    {
        /// <summary>
        /// 一个控制摄像头的类
        /// </summary>
        public class Pick
        {
            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;

            /// <summary>
            /// 初始化摄像头
            /// </summary>
            /// <param name="handle">控件的句柄</param>
            /// <param name="left">开始显示的左边距</param>
            /// <param name="top">开始显示的上边距</param>
            /// <param name="width">要显示的宽度</param>
            /// <param name="height">要显示的长度</param>
            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, long lParam);
            [DllImport("avicap32.dll")]
            public static extern bool capGetDriverDescriptionA(short wDriver, byte[] lpszName, int cbName, byte[] lpszVer, int cbVer);

            /// <summary>
            /// 开始显示图像
            /// </summary>
            public void Start()
            {
                if (bStat)
                    return;

                bStat = true;
                byte[] lpszName = new byte[100];

                //int ihWndc = capCreateCaptureWindowA("WebCap", WS_CHILD | WS_VISIBLE, mLeft, mTop, mWidth, mHeight, mControlPtr.ToInt32(), 0);
                capGetDriverDescriptionA(0, lpszName, 100,new byte[100], 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;


            }

            /// <summary>
            /// 停止显示
            /// </summary>
            public void Stop()
            {
                SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
                bStat = false;
            }

            /// <summary>
            /// 抓图
            /// </summary>
            /// <param name="path">要保存bmp文件的路径</param>
            public void GrabImage(string path)
            {

                IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);
                SendMessage(hWndC, WM_CAP_SAVEDIB, 0, hBmp.ToInt64());

            }

            /// <summary>
            /// 录像
            /// </summary>
            /// <param name="path">要保存avi文件的路径</param>
            public void Kinescope(string path)
            {
                IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);
                SendMessage(hWndC, WM_CAP_FILE_SET_CAPTURE_FILEA, 0, hBmp.ToInt64());
                SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0);
            }

            /// <summary>
            /// 停止录像
            /// </summary>
            public void StopKinescope()
            {
                SendMessage(hWndC, WM_CAP_STOP, 0, 0);
            }

        }
    }

    注:

    hWndC = capCreateCaptureWindowA(lpszName, WS_CHILD+ WS_VISIBLE, mLeft, mTop, mWidth, mHeight, mControlPtr, 0);

    这一句不管怎么都是返回0.让我很无语。

    窗体中的调用也是平淡无奇,窗体包含一个pictureBox控件,handle也能够传入pick

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;
    using System.Runtime.InteropServices;

    namespace Camera
    {
        public partial class Form1 : Form
        {
            [DllImport("user32.dll")]
            public static extern IntPtr GetDC(IntPtr hWnd);


            public Form1()
            {
                InitializeComponent();
            }

            private void button1_Click(object sender, EventArgs e)
            {
                Pick MyPick =
                    new Pick((GetDC(this.pictureBox1.Handle)),
                        0,
                        0,
                        pictureBox1.Width,
                        pictureBox1.Height);
                MyPick.Start();


            }
        }
    }

    请高手指点一二,谢谢了。

    我的usb摄像头在windows里面使用一点问题没有,别人写的程序也是能用的。抓狂中。

     

     

    2010年4月13日 8:19

答案

  • VFW是DirectShow的前身,摄像头驱动未必支持。新的程序应该使用DirectShow。参考DirectShow SDK中的amcap示例。

    The following is signature, not part of post
    Please mark the post answered your question as the answer, and mark other helpful posts as helpful.
    Visual C++ MVP
    2010年4月14日 0:17
    版主

全部回复

  • VFW是DirectShow的前身,摄像头驱动未必支持。新的程序应该使用DirectShow。参考DirectShow SDK中的amcap示例。

    The following is signature, not part of post
    Please mark the post answered your question as the answer, and mark other helpful posts as helpful.
    Visual C++ MVP
    2010年4月14日 0:17
    版主
  • 嗯,谢谢了,我这就去看看哈。
    2010年4月15日 1:10