海康监控设备在国内相关领域占有很大的份额，至少目前我接触到的项目或公司都是使用海康设备进行监控的。所以本文主要针对海康设备来进行视频流的获取。
视频流
1 概念说明
硬盘录像机：海康产品的硬盘录像机分为DVR、NVR和CVR三种，DVR是模拟机和同轴缆信号的硬盘录像机，不需要配置IP；NVR是网络型录像机，必须配置IP；CVR是更高级的NVR或者DVR，数据集中存储的NVR（预研用硬盘录像机为CVR）。
2 技术实现
技术实现
海康监控设备视频流获取技术以上技术路线图所示，首先初始化SDK，其次设置连接超时时间、重连时间与异常消息回调函数；接着通过提供硬盘录像机IP、账号、密码、端口号等信息进行登录；然后通过设置播放句柄、通道、流类型、连接方式、是否阻塞等播放信息来进行播放，同时通过设置播放回调函数来获取实时视频流；之后通过软解码技术将视频流逐帧解码为YU12格式，然后编写算法将YU12格式数据转换为RGBA数据，从而完成整个过程的操作。
3 示例代码
该技术用到的海康SDK包括HCNetSDK.lib、HCNetSDK.dll、PlayCtrl.lib、PlayCtr.dll，并使用opencv进行视频的试试显示。具体示例代码如下所示：
#include "Windows.h"
#include "HCNetSDK.h"
#include <stdio.h>
#include <time.h>
#include "plaympeg4.h"
#include "opencv/cv.h"
#include "opencv2/photo.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
void CALLBACK g_ExceptionCallBack(DWORD dwType, LONG IUserID, LONG IHandle, void *pUser)
{
char tempbuf[256] = {};
switch (dwType)
{
case EXCEPTION_RECONNECT:
printf("--------reconnect-------%d\n", time(NULL));
break;
default:
break;
}
}
bool YV12_to_RGB32(unsigned char* pYV12, unsigned char* pRGB32, int iWidth, int iHeight)
{
if (!pYV12 || !pRGB32)
return false;
const long nYLen = long(iHeight * iWidth);
const int nHfWidth = (iWidth >> 1);
if (nYLen < 1 || nHfWidth < 1)
return false;
unsigned char* yData = pYV12;
unsigned char* vData = pYV12 + iWidth*iHeight + (iHeight / 2)*(iWidth / 2);//&vData[nYLen >> 2];
unsigned char* uData = pYV12 + iWidth*iHeight;// &yData[nYLen];
if (!uData || !vData)
return false;
int rgb[4];
int jCol, iRow;
for (iRow = 0; iRow < iHeight; iRow++)
{
for (jCol = 0; jCol < iWidth; jCol++)
{
rgb[3] = 1;
int Y = yData[iRow*iWidth + jCol];
int U = uData[(iRow / 2)*(iWidth / 2) + (jCol / 2)];
int V = vData[(iRow / 2)*(iWidth / 2) + (jCol / 2)];
int R = Y + (U - 128) + (((U - 128) * 103) >> 8);
int G = Y - (((V - 128) * 88) >> 8) - (((U - 128) * 183) >> 8);
int B = Y + (V - 128) + (((V - 128) * 198) >> 8);
// r分量值
R = R < 0 ? 0 : R;
rgb[2] = R > 255 ? 255 : R;
// g分量值
G = G < 0 ? 0 : G;
rgb[1] = G > 255 ? 255 : G;
// b分量值
B = B < 0 ? 0 : B;
rgb[0] = B > 255 ? 255 : B;
pRGB32[4 * (iRow*iWidth + jCol) + 0] = rgb[0];
pRGB32[4 * (iRow*iWidth + jCol) + 1] = rgb[1];
pRGB32[4 * (iRow*iWidth + jCol) + 2] = rgb[2];
pRGB32[4 * (iRow*iWidth + jCol) + 3] = rgb[3];
}
}
return true;
}
void CALLBACK g_DecCBFun(long nPort, char* pBuf, long nSize, FRAME_INFO* pFrameInfo, long nReserved1, long nReserved2)
{
long lFrameType = pFrameInfo->nType;
if (lFrameType == T_AUDIO16)
{
//printf("Audio nStap:%d\n", pFrameInfo->nStamp);
}
else if (lFrameType == T_YV12)
{
char* rgba = new char[pFrameInfo->nHeight * pFrameInfo->nWidth * 4];
// YV12_to_RGB24((unsigned char*)pBuf, (unsigned char*)rgb, pFrameInfo->nWidth, pFrameInfo->nHeight);
YV12_to_RGB32((unsigned char*)pBuf, (unsigned char*)rgba, pFrameInfo->nWidth, pFrameInfo->nHeight);
cv::Mat img(pFrameInfo->nHeight,pFrameInfo->nWidth,CV_8UC4,rgba);
cv::resize(img, img, cv::Size(img.size().width*0.5, img.size().height*0.5));
cv::imshow("video", img);
cv::waitKey(1);
}
}
LONG nPort = -1;
void CALLBACK g_RealDataCallBack(LONG IRealHandle, DWORD dwDataType, BYTE *pBuffer, DWORD dwBufSize, void* pUser)
{
DWORD dRet = 0;
BOOL inData = FALSE;
switch (dwDataType)
{
case NET_DVR_SYSHEAD:
if (!PlayM4_GetPort(&nPort))
{
break;
}
if (!PlayM4_OpenStream(nPort,pBuffer,dwBufSize,1024*1024))
{
dRet = PlayM4_GetLastError(nPort);
break;
}
if (!PlayM4_SetDecCallBack(nPort,g_DecCBFun))
{
dRet = PlayM4_GetLastError(nPort);
break;
}
if (!PlayM4_Play(nPort,NULL))
{
dRet = PlayM4_GetLastError(nPort);
break;
}
case NET_DVR_STREAMDATA:
if (dwBufSize > 0 && nPort != -1)
{
inData = PlayM4_InputData(nPort, pBuffer, dwBufSize);
while (!inData)
{
Sleep(10);
inData = PlayM4_InputData(nPort, pBuffer, dwBufSize);
printf("PlayM4_InputData faild %d\n",PlayM4_GetLastError(nPort));
}
}
break;
default:
inData = PlayM4_InputData(nPort, pBuffer, dwBufSize);
while (!inData)
{
Sleep(10);
inData = PlayM4_InputData(nPort, pBuffer, dwBufSize);
OutputDebugString("PlayM4_InputData failed 2\n");
}
break;
}
}
void main()
{
//init sdk
NET_DVR_Init();
//set reconnect time
NET_DVR_SetConnectTime(2000, 1);
NET_DVR_SetReconnect(10000, true);
//set recall func
NET_DVR_SetExceptionCallBack_V30(0, NULL, g_ExceptionCallBack, NULL);
//get console handler
//register device
LONG IUserID;
NET_DVR_USER_LOGIN_INFO struLoginInfo = { 0 };
NET_DVR_DEVICEINFO_V40 struDeviceInfo = { 0 };
strcpy_s((char*)struLoginInfo.sDeviceAddress, sizeof(struLoginInfo.sDeviceAddress), "192.168.3.62");
strcpy_s((char*)struLoginInfo.sUserName,sizeof(struLoginInfo.sUserName), "admin");
strcpy_s((char*)struLoginInfo.sPassword,sizeof(struLoginInfo.sPassword), "abcd-1234");
struLoginInfo.wPort = 8000;
struLoginInfo.bUseAsynLogin = 0;
IUserID = NET_DVR_Login_V40(&struLoginInfo, &struDeviceInfo);
if (IUserID < 0)
{
printf("login failed, error code:%d\n", NET_DVR_GetLastError());
NET_DVR_Cleanup();
return;
}
// printf("channel num:%d\n", struDeviceInfo.struDeviceV30.byChanNum);
// printf("start channel:%d\n", struDeviceInfo.struDeviceV30.byStartChan);
NET_DVR_IPPARACFG_V40 IpAccessCfg;
memset(&IpAccessCfg, 0, sizeof(IpAccessCfg));
DWORD dwReturned;
if (!NET_DVR_GetDVRConfig(IUserID, NET_DVR_GET_IPPARACFG_V40, 0, &IpAccessCfg, sizeof(NET_DVR_IPPARACFG_V40), &dwReturned))
{
return;
}
LONG channel;
for (int i = 0; i < MAX_IP_CHANNEL; ++i)
{
if (IpAccessCfg.struStreamMode[i].uGetStream.struChanInfo.byEnable)
{
channel = i + IpAccessCfg.dwStartDChan;
break;
}
}
//display
LONG IRealPlayHandle;
NET_DVR_PREVIEWINFO struPlayInfo = { 0 };
struPlayInfo.hPlayWnd = NULL;
struPlayInfo.lChannel = channel;
struPlayInfo.dwStreamType = 0;
struPlayInfo.dwLinkMode = 0;
struPlayInfo.bBlocked = 1;
//
// NET_DVR_CLIENTINFO ClientInfo;
// ClientInfo.hPlayWnd = hWnd;
// ClientInfo.lChannel = 0;
// ClientInfo.lLinkMode = 0;
// ClientInfo.sMultiCastIP = NULL;
// //TRACE("Channel number:%d\n", ClientInfo.lChannel);
// IRealPlayHandle = NET_DVR_RealPlay_V30(IUserID, &ClientInfo, NULL, NULL, TRUE);
IRealPlayHandle = NET_DVR_RealPlay_V40(IUserID, &struPlayInfo, g_RealDataCallBack, NULL);
if (IRealPlayHandle<0)
{
printf("play failed, error code:%d\n", NET_DVR_GetLastError());
NET_DVR_Logout(IUserID);
NET_DVR_Cleanup();
return;
}
Sleep(10000000000000000);
//close display
NET_DVR_StopRealPlay(IRealPlayHandle);
//logout
NET_DVR_Logout(IUserID);
//release
NET_DVR_Cleanup();
return;
}
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