基于大华网络摄像头SDK开发抓图工具类（C++）

【前言】

众所周知，大华网络摄像头没有直接提供相应的ROS驱动包，所以我们理论上有两个办法在C++中获取网络摄像头图像：

一是通过OpenCV（FFmpeg）的videocapture类去抓取图像；

二是通过大华官方提供的SDK，自己封装一个抓图工具类。

这里主要讲述第二种方法。

【资源】

大华SDK下载地址

supporthttps://support.dahuatech.com/tools/sdkExploit/24

【干货】

1、先搞一个放数据结构的类

#ifndef USERDEFINE_H
#define USERDEFINE_H#include "dhnetsdk.h"
#include "dhconfigsdk.h"
#include <list>
#include <vector>typedef struct
{LLONG lRealPlayHandle;unsigned long dwStatistic;
} DH_Channel_Info;typedef struct
{LLONG lLoginHandle;int nChannelCount;char szDevIp[32];int nPort;char szUserName[32];char szPassWord[32];DH_Channel_Info channel[16];
} DH_Device_Info;typedef std::list<DH_Device_Info*> DEVICE_LIST;
extern DEVICE_LIST g_DeviceList;typedef std::vector<unsigned char> ONE_IMAGE_BUFFER;
extern ONE_IMAGE_BUFFER g_ImageBuffer;extern bool g_SnapSuccFlag;#endif

2、再搞一个接口类，用来封装SDK的API

#include "UserDefine.h"
#include <stdio.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <string>
#include <map>class DHCamera
{
public:DHCamera();~DHCamera();bool initSDKClient();void initDeviceInfo(DH_Device_Info &stDeviceInfo);void loadDeviceInfo();void loginDev();void grabCamImage(LLONG loginHandle);void logoutDev();public:std::map<std::string, LLONG> devHandles_map;
};

3、再来看一下类的具体实现吧

#include "DHCamera.h"DEVICE_LIST g_DeviceList;
ONE_IMAGE_BUFFER g_ImageBuffer;
bool g_SnapSuccFlag = false;
static bool g_bNetSDKInitFlag = false;
static short g_nCmdSerial = 0;void CALLBACK DisConnectFunc(LLONG lLoginID, char *pchDVRIP, LONG nDVRPort, LDWORD dwUser)
{DHCamera* pThis = (DHCamera *)dwUser;if(NULL == pThis){return;}printf("Call DisConnectFunc\n");printf("lLoginID[0x%x]", lLoginID);if (NULL != pchDVRIP){printf("pchDVRIP[%s]\n", pchDVRIP);}printf("nDVRPort[%d]\n", nDVRPort);printf("dwUser[%p]\n", dwUser);printf("\n");return;
}void CALLBACK HaveReConnect(LLONG lLoginID, char *pchDVRIP, LONG nDVRPort, LDWORD dwUser)
{printf("Call HaveReConnect\n");printf("lLoginID[0x%x]", lLoginID);if (NULL != pchDVRIP){printf("pchDVRIP[%s]\n", pchDVRIP);}printf("nDVRPort[%d]\n", nDVRPort);printf("dwUser[%p]\n", dwUser);printf("\n");
}void CALLBACK SnapRev(LLONG lLoginID, BYTE *pBuf, UINT RevLen, UINT EncodeType, DWORD CmdSerial, LDWORD dwUser)
{std::vector<unsigned char> current_frame(pBuf, pBuf+RevLen);g_ImageBuffer.swap(current_frame);g_SnapSuccFlag = true;
}DHCamera::DHCamera()
{
}DHCamera::~DHCamera()
{DEVICE_LIST::iterator it = g_DeviceList.begin();while (it != g_DeviceList.end()){DH_Device_Info *pDeviceInfo = (*it);if (pDeviceInfo != nullptr){delete pDeviceInfo;pDeviceInfo = nullptr;}it++;}g_DeviceList.clear();
}bool DHCamera::initSDKClient()
{g_bNetSDKInitFlag = CLIENT_Init(DisConnectFunc, (LDWORD)this);CLIENT_SetAutoReconnect(HaveReConnect, 0);return g_bNetSDKInitFlag;
}void DHCamera::initDeviceInfo(DH_Device_Info &stDeviceInfo)
{stDeviceInfo.lLoginHandle = 0UL;stDeviceInfo.nChannelCount = 0;stDeviceInfo.nPort = 0;memset(&stDeviceInfo.szDevIp , 0 , sizeof(stDeviceInfo.szDevIp));memset(&stDeviceInfo.szUserName , 0 , sizeof(stDeviceInfo.szUserName));memset(&stDeviceInfo.szPassWord , 0 , sizeof(stDeviceInfo.szPassWord));memset(&stDeviceInfo.channel , 0 , sizeof(stDeviceInfo.channel));
}void DHCamera::loadDeviceInfo()
{DEVICE_LIST::iterator it = g_DeviceList.begin();while (it != g_DeviceList.end()){DH_Device_Info *pDeviceInfo = (*it);if (pDeviceInfo != nullptr){delete pDeviceInfo;pDeviceInfo = nullptr;}it++;}g_DeviceList.clear();int start_ip = 150;int connect_num = 12;int port = 37777;for(int i = start_ip; i < (start_ip + connect_num); i++){DH_Device_Info* device_info = new DH_Device_Info;initDeviceInfo(*device_info);std::string ip = "192.168.1.";strncpy(device_info->szDevIp, (ip+std::to_string(i)).c_str(), sizeof(device_info->szDevIp)-1);device_info->nPort = port;strncpy(device_info->szUserName, "admin", sizeof(device_info->szUserName)-1);strncpy(device_info->szPassWord, "admin123", sizeof(device_info->szPassWord)-1);g_DeviceList.push_back(device_info);}printf("Init Dev's Num : %d\n", g_DeviceList.size());
}void DHCamera::loginDev()
{DEVICE_LIST::iterator it = g_DeviceList.begin();while(it != g_DeviceList.end()){DH_Device_Info *pDeviceInfo = (*it);if(pDeviceInfo == NULL){it++;continue;}NET_IN_LOGIN_WITH_HIGHLEVEL_SECURITY stInparam;memset(&stInparam, 0, sizeof(stInparam));stInparam.dwSize = sizeof(stInparam);strncpy(stInparam.szIP, pDeviceInfo->szDevIp, sizeof(stInparam.szIP) - 1);strncpy(stInparam.szPassword, pDeviceInfo->szPassWord, sizeof(stInparam.szPassword) - 1);strncpy(stInparam.szUserName, pDeviceInfo->szUserName, sizeof(stInparam.szUserName) - 1);stInparam.nPort = pDeviceInfo->nPort;stInparam.emSpecCap = EM_LOGIN_SPEC_CAP_TCP;NET_OUT_LOGIN_WITH_HIGHLEVEL_SECURITY stOutparam;memset(&stOutparam, 0, sizeof(stOutparam));stOutparam.dwSize = sizeof(stOutparam);pDeviceInfo->lLoginHandle = CLIENT_LoginWithHighLevelSecurity(&stInparam, &stOutparam);if(pDeviceInfo->lLoginHandle != 0){devHandles_map.emplace(pDeviceInfo->szDevIp, pDeviceInfo->lLoginHandle);printf("CLIENT_LoginWithHighLevelSecurity %s[%d] Success\n" , pDeviceInfo->szDevIp , pDeviceInfo->nPort);usleep(500000);}else {printf("Failed to login IP[%s]\n", pDeviceInfo->szDevIp);}}
}void DHCamera::logoutDev()
{DEVICE_LIST::iterator it = g_DeviceList.begin();while(it != g_DeviceList.end()){if((*it)->lLoginHandle != 0){CLIENT_Logout((*it)->lLoginHandle);}}if (TRUE == g_bNetSDKInitFlag){CLIENT_Cleanup();g_bNetSDKInitFlag = FALSE;}
}void DHCamera::grabCamImage(long loginHandle)
{if (0 == loginHandle){return;}// 设置抓图回调函数CLIENT_SetSnapRevCallBack(SnapRev, NULL);//事例中默认通道 ID 为 0、抓图模式为抓一幅图,用户可根据实际情况自行选择int nChannelId = 0;int nSnapType = 0; // 抓图模式;-1:表示停止抓图, 0:表示请求一帧, 1:表示定时发送请求, 2:表示连续请求// 发送抓图命令给前端设备SNAP_PARAMS stuSnapParams;stuSnapParams.Channel = nChannelId;stuSnapParams.mode = nSnapType;stuSnapParams.CmdSerial = ++g_nCmdSerial; // 请求序列号,有效值范围 0~65535,超过范围会被截断为 unsigned shortif (FALSE == CLIENT_SnapPictureEx(loginHandle, &stuSnapParams)){printf("CLIENT_SnapPictureEx Failed!Last Error[%x]\n", CLIENT_GetLastError());return;}else{printf("CLIENT_SnapPictureEx succ\n");}
}

【后言】

如果这篇博客对你有帮助，就点个赞呗！