C# 視訊監控系列（6）：服務端 SDK 封裝（上）——HikServer.dll 網路服務 API

本文提供 HikServer.dll（網路服務層）的完整 C# P/Invoke 封裝，涵蓋服務啟動/停止、客戶端驗證、碼流寫入、訊息收發、多播設定、緩衝區控制等核心 API，並定義必要的結構體、委派與枚舉。

核心結構與枚舉

[StructLayout(LayoutKind.Sequential)]
public struct PSERVER_VIDEOINFO
{
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 64)]
    public byte[] m_datatype;
    public byte m_channum;
    public int m_waittime;
    public ulong m_bufnum;
}

public enum ChannelDataType { NORMAL = 50, DIALING, SMALLPIC }

回調委派定義

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public delegate void SetIBP(int port, int framerat);

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public delegate void MakeIFrame(ulong port);

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public delegate void StartCap(int nChannel);

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public delegate void StopCap(int nChannel);

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public delegate int CheckPassword(string username, ushort namelen, string password, ushort passlen);

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
public delegate int CheckIP(int nChannel, string nIP);

核心 API 宣告（節錄）

public static class HikServer
{
    public static readonly uint WM_USER = 0x0400;

    [DllImport("HikServer.dll")]
    public static extern int MP4_ServerStart(ref PSERVER_VIDEOINFO videoinfo);

    [DllImport("HikServer.dll")]
    public static extern bool MP4_ServerStop();

    [DllImport("HikServer.dll")]
    public static extern bool MP4_ServerGetState(out ushort clientnum);

    [DllImport("HikServer.dll")]
    public static extern void MP4_ServerSetMessage(uint nMessage, IntPtr hWnd);

    [DllImport("HikServer.dll")]
    public static extern void MP4_ServerCheckIP(CheckIP cip);

    [DllImport("HikServer.dll")]
    public static extern void MP4_ServerCheckPassword(CheckPassword cp);

    [DllImport("HikServer.dll")]
    public static extern void MP4_ServerWriteDataEx(int nPort, IntPtr pPacketBuffer, int nPacketSize, int frameType, int breakable, int nImgFormat);

    [DllImport("HikServer.dll")]
    public static extern void MP4_ServerSetStart(StartCap sc);

    [DllImport("HikServer.dll")]
    public static extern void MP4_ServerSetStop(StopCap sc);

    [DllImport("HikServer.dll")]
    public static extern void MP4_ServerSetCapIFrame(MakeIFrame mf);

    [DllImport("HikServer.dll")]
    public static extern int MP4_ServerSetNetPort(ushort dServerPort, ushort dClientPort);

    [DllImport("HikServer.dll")]
    public static extern int MP4_ServerSetTTL(byte cTTLVal);

    [DllImport("HikServer.dll")]
    public static extern int MP4_ServerSetBufNum(ushort nChannel, ushort dBufNum);

    [DllImport("HikServer.dll")]
    public static extern bool MP4_ServerCastGroup(bool bSet, ulong dChannel, string sIP, ushort wPort);

    [DllImport("HikServer.dll")]
    public static extern int MP4_ServerMaxUser(uint dwChannel, int nMaxNum);

    [DllImport("HikServer.dll")]
    public static extern ulong MP4_ServerGetSdkVersion();
}

重要修正記錄

• 2009-08-19：MP4_ServerReadLastMessage 字串參數改為 StringBuilder，避免記憶體存取錯誤。
  修正前：string m_sIP, string m_sCommand, out ushort m_wLen
  修正後：StringBuilder m_sIP, StringBuilder m_sCommand, out ushort m_wLen
• 所有回調委派均標記 [UnmanagedFunctionPointer(CallingConvention.StdCall)]。
• MP4_ServerWriteDataEx 使用 IntPtr 接收緩衝指標，配合 Marshal.Copy 讀取資料。

使用建議

1. 將封裝類別置於獨立專案 HikServerWrapper，供服務端與播放器專案共同引用。
2. 啟動流程：SetMessage → CheckIP/Password → SetStart/SetCapIFrame → SetBufNum → ServerStart。
3. 碼流寫入：在 STREAM_DIRECT_READ_CALLBACK 中呼叫 MP4_ServerWriteDataEx，nImgFormat=0 主碼流、1 子碼流。
4. 隨時關注本系列後續文章，API 封裝會持續修正補全。