哪位高手能帮我解释一下这段c#视频头操作程序
private int hHwnd; //句柄
public struct videohdr_tag
{
public byte[] lpData;
public int dwBufferLength;
public int dwBytesUsed;
public int dwTimeCaptured;
public int dwUser;
public int dwFlags;
public int[] dwReserved; }
public delegate bool CallBack(int hwnd, int lParam);
/// <summary>
/// 必需的设计器变量。
/// </summary>
[DllImport("avicap32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
public static extern int capCreateCaptureWindowA([MarshalAs(UnmanagedType.VBByRefStr)] ref string lpszWindowName, int dwStyle, int x, int y, int nWidth, short nHeight, int hWndParent, int nID);
[DllImport("avicap32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
public static extern bool capGetDriverDescriptionA(short wDriver, [MarshalAs(UnmanagedType.VBByRefStr)] ref string lpszName, int cbName, [MarshalAs(UnmanagedType.VBByRefStr)] ref string lpszVer, int cbVer);
[DllImport("user32", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
public static extern bool DestroyWindow(int hndw);
[DllImport("user32", EntryPoint = "SendMessageA", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
public static extern int SendMessage(int hwnd, int wMsg, int wParam, [MarshalAs(UnmanagedType.AsAny)] object lParam);
[DllImport("user32", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
public static extern int SetWindowPos(int hwnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
[DllImport("vfw32.dll")]
public static extern string capVideoStreamCallback(int hwnd, videohdr_tag videohdr_tag);
[DllImport("vicap32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
public static extern bool capSetCallbackOnFrame(int hwnd, string s);
private void OpenCapture()
{ int intWidth = this.panel1.Width;
int intHeight = this.panel1.Height;
int intDevice = 0;
string refDevice = intDevice.ToString();
hHwnd = Form1.capCreateCaptureWindowA(ref refDevice, 1342177280, 0, 0, 640, 480, this.panel1.Handle.ToInt32(), 0);
if (Form1.SendMessage(hHwnd, 0x40a, intDevice, 0) > 0)
{
Form1.SendMessage(this.hHwnd, 0x435, -1, 0);
Form1.SendMessage(this.hHwnd, 0x434, 0x42, 0);
Form1.SendMessage(this.hHwnd, 0x432, -1, 0);
Form1.SetWindowPos(this.hHwnd, 1, 0, 0, intWidth, intHeight, 6);
}
else
{
Form1.DestroyWindow(this.hHwnd);
}
}
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