usb 摄像头编程
小弟 做了一个摄像头监控程序 usb无驱的 调试预览时一直黑屏，抓拍图片保存无图像 ，但录像保存后却正常。。。请问一下是什么原因哪？多多指教
--------------------编程问答-------------------- 专业打捞沉贴
--------------------编程问答--------------------
和我的情况一样using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
namespace WindowsApplication2
{
//视频API调用
public class VideoAPI
{
[System.Runtime.InteropServices.DllImport("avicap32.dll")]
public static extern IntPtr capCreateCaptureWindowA(byte[] lpszWindowName, int dwStyle, int x, int y, int Width,
int nHeight, IntPtr hWndParent, int nID);
[System.Runtime.InteropServices.DllImport("avicap32.dll")]
public static extern bool capGetDriverDescriptionA(short wDriver, byte[] lpszName, int cbName, byte[] lpszVer, int cbVer);
[DllImport("User32.dll")] public static extern bool SendMessage(IntPtr hWnd, int wMsg, bool wParam, int lParam);
[DllImport("User32.dll")] public static extern bool SendMessage(IntPtr hWnd, int wMsg, short wParam, int lParam);
// 常量
public const int WM_USER = 0x400;
public const int WS_CHILD = 0x40000000;
public const int WS_VISIBLE = 0x10000000;
public const int SWP_NOMOVE = 0x2;
public const int SWP_NOZORDER = 0x4;
public const int WM_CAP_DRIVER_CONNECT = WM_USER + 10;
public const int WM_CAP_DISCONNECT = WM_USER + 11;
public const int WM_CAP_SET_CALLBACK_FRAME = WM_USER + 5;
public const int WM_CAP_SET_PREVIEW = WM_USER + 50;
public const int WM_CAP_SET_PREVIEWRATE = WM_USER + 52;
public const int WM_CAP_SET_VIDEOFORMAT = WM_USER + 45;
public const int WM_CAP_START = WM_USER;
public const int WM_CAP_SAVEDIB = WM_CAP_START + 25;
public void cla()
{
}
}
public class cVideo
{
private IntPtr lwndC; //保存无符号句柄
private IntPtr mControlPtr; //保存管理指示器
private int mWidth;
private int mHeigth;
public cVideo(IntPtr handle, int width, int heigth)
{
mControlPtr = handle;
mWidth = width;
mHeigth = heigth;
}
/// <summary>
/// 打开视频设备
/// </summary>
public void StartWebCam()
{
byte[] lpszName = new byte[100];
byte[] lpszVer = new byte[100];
VideoAPI.capGetDriverDescriptionA(0, lpszName, 100, lpszVer, 100);
this.lwndC = VideoAPI.capCreateCaptureWindowA(lpszName, VideoAPI.WS_CHILD | VideoAPI.WS_VISIBLE, 0, 0,
mWidth, mHeigth, mControlPtr, 0);
if (VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_DRIVER_CONNECT, 0, 0))
{
VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_PREVIEWRATE, 100, 0);
VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_PREVIEW, true, 0);
}
}
/// <summary>
///拍照
/// </summary>
/// <param name="hWndC"></param>
/// <param name="path">路径</param>
public void GrabImage(IntPtr hWndC, string path)
{
IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);
VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SAVEDIB, 0, hBmp.ToInt32());
}
}
}
--------------------------------分割线（以下为窗体上的代码）-------------------------------------
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace WindowsApplication2
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void btnOpen_Click(object sender, EventArgs e)
{
btnOpen.Enabled = false;
btnCloes.Enabled = true;
btnToImage.Enabled = true;
cVideo video = new cVideo(pictureBox1.Handle, pictureBox1.Width, pictureBox1.Height);
video.StartWebCam();
}
private void btnToImage_Click(object sender, EventArgs e)
{
cVideo video = new cVideo(pictureBox1.Handle, pictureBox1.Width, pictureBox1.Height);
video.GrabImage(pictureBox1.Handle,"d:\\a.bmp");
}
}
}
但是我换了一台电脑试了一下
就能显示。
--------------------编程问答-------------------- 我的也是这样。那位知道是怎么回事哦。 --------------------编程问答-------------------- 快点解决啊 --------------------编程问答-------------------- 急用啊 --------------------编程问答-------------------- 帮顶。。。。。。。。因为我也在搞摄像头 不过是5.0的
补充：.NET技术 , C#
