c#播放海康mp4视频

你可以使用海康提供的 SDK (如 HCNetSDK 或者 EZ_SDK) 来播放海康的 MP4 视频。以下是一些示例代码，用于在 C# 中使用 HCNetSDK 播放海康 MP4 视频：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace HCNetSDKTest
{
    public partial class Form1 : Form
    {
        // HCNetSDK.dll 的路径
        const string HCNetSDKDllPath = "HCNetSDK.dll";

        // 登录句柄
        private int iLoginID = -1;

        // 播放句柄
        private int iPlayID = -1;

        // 播放窗口
        private IntPtr hWnd;

        // SDK 初始化
        [DllImport(HCNetSDKDllPath)]
        private static extern bool NET_DVR_Init();

        // SDK 释放
        [DllImport(HCNetSDKDllPath)]
        private static extern bool NET_DVR_Cleanup();

        // 用户登录
        [DllImport(HCNetSDKDllPath)]
        private static extern int NET_DVR_Login_V30(string sDVRIP, ushort wDVRPort, string sUserName, string sPassword, ref NET_DVR_DEVICEINFO_V30 lpDeviceInfo);

        // 用户注销
        [DllImport(HCNetSDKDllPath)]
        private static extern bool NET_DVR_Logout(int iLoginID);

        // 打开实时预览
        [DllImport(HCNetSDKDllPath)]
        private static extern int NET_DVR_RealPlay_V40(int iUserID, ref NET_DVR_PREVIEWINFO lpPreviewInfo, REALDATACALLBACK fRealDataCallback_V30, IntPtr pUser);

        // 关闭预览
        [DllImport(HCNetSDKDllPath)]
        private static extern bool NET_DVR_StopRealPlay(int iPlayHandle);

        // 视频数据回调函数
        public delegate void REALDATACALLBACK(int lRealHandle, uint dwDataType, IntPtr pBuffer, uint dwBufSize, IntPtr pUser);

        // 预览参数结构体
        public struct NET_DVR_PREVIEWINFO
        {
            public int lChannel;
            public uint dwStreamType;
            public uint dwLinkMode;
            public IntPtr hPlayWnd;
            public uint bBlocked;
            public uint bPassbackRecord;
            public uint byPreviewMode;
            public uint byStreamID;
            public byte[] byReserve;
        }

        // 设备信息结构体
        [StructLayout(LayoutKind.Sequential)]
        public struct NET_DVR_DEVICEINFO_V30
        {
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 48)]
            public string sSerialNumber;
            public byte byAlarmInPortNum;
            public byte byAlarmOutPortNum;
            public byte byDiskNum;
            public byte byDVRType;
            public byte byChanNum;
            public byte byStartChan;
            public byte byAudioChanNum;
            public byte byIPChanNum;
            public byte byZeroChanNum;
            public byte byMainProto;
            public byte bySubProto;
            public byte bySupport;
            public byte bySupport1;
            public byte byRes1;
            public short wDevType;
            public byte byRes2;
            public byte bySupport2;
            public ushort wFirmwareVersion;
            public ushort wNetProtoVersion;
            public ushort wUserProtoVersion;
            public ushort wSignalVersion;
            public ushort wIrdaVersion;
            public byte byRes3;
            public byte byHardwareVersion;
            public byte bySoftwareVersion;
            public byte byMiddleWareVersion;
            public byte byBuildDate;
            public byte byModifyDate;
            public byte byRes4;
            public byte byDevicePerformanceLevel;
            public byte byReserve2;
        }

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // SDK 初始化
            NET_DVR_Init();

            // 获取播放窗口句柄
            hWnd = pictureBox1.Handle;

            // 登录
            NET_DVR_DEVICEINFO_V30 devInfo = new NET_DVR_DEVICEINFO_V30();
            iLoginID = NET_DVR_Login_V30("192.168.1.64", 8000, "admin", "12345", ref devInfo);

            // 设置预览参数
            NET_DVR_PREVIEWINFO previewInfo = new NET_DVR_PREVIEWINFO();
            previewInfo.lChannel = 1; // 通道号
            previewInfo.dwStreamType = 0; // 码流类型：0-主码流，1-子码流，2-码流3，3-码流4，以此类推
            previewInfo.dwLinkMode = 0; // 连接模式：0-TCP，1-UDP，2-多播，3-RTP，4-RTP/RTSP，5-RSTP/HTTP
            previewInfo.hPlayWnd = hWnd; // 播放窗口句柄
            previewInfo.bBlocked = 1; // 阻塞取流：1-是，0-否
            previewInfo.byPreviewMode = 0; // 预览模式：0-正常预览，1-延迟预览
            previewInfo.byPassbackRecord = 0; // 是否启用录像回传：0-不启用，1-启用
            previewInfo.byStreamID = 1; // 码流ID，取值范围为从0开始的32个整数
            previewInfo.byReserve = new byte[216]; // 保留字段

            // 打开实时预览
            iPlayID = NET_DVR_RealPlay_V40(iLoginID, ref previewInfo, null, IntPtr.Zero);
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            // 关闭预览
            NET_DVR_StopRealPlay(iPlayID);

            // 注销
            NET_DVR_Logout(iLoginID);

            // SDK 释放
            NET_DVR_Cleanup();
        }
    }
}

请注意，上述示例代码仅提供了基本的播放功能，并没有进行错误处理和异常处理。在实际应用中，您需要根据具体情况进行完善。