1. 問題描寫
最近在搭建1個可視傳感網，在調試早期就遇到了1個很奇怪的問題：
一樣的型號的攝像機，一樣的程序，有1部份攝像頭正常工作，而有1大部份的不能正常解碼顯示。這個小demo是我使用海康SDK里面實例寫的。文章的最后給出項目的代碼，有興趣的也能夠跑跑程序，其實只是1個簡單的例程而已，寫在這里只是為了方便往后歸納總結。這里使用的海康網絡攝像頭型號是：DS⑵CD852MF-E。
代碼中，攝像頭的登錄函數為：NET_DVR_Login_V30，播放函數：NET_DVR_RealPlay_V40。
在回調解碼函數處設置斷點，能跳到此函數中：
但是除ip為192.168.2.21和192.168.2.22這兩個網絡攝像機，換成其他的攝像機都顯示不了。但是另外一方面，網絡攝像頭的登錄沒有問題，但是就是沒有畫面。
單步調試,看到lRealHandle = NET_DVR_RealPlay_V40(lUserID, &struPlayInfo, g_RealDataCallBack_V30, NULL);lRealHandle值為0，表示沒有問題的啊…但是在回調函數設置斷點卻進不去，就說明沒有回調解碼。跟上面的區分就在這里。但是代碼是1模1樣的，攝像機型號都是1樣的852MF-E，因此不知道問題出在哪里。
2. 解決方法
以上問題可簡單描寫為，1個可用的程序，但對1部份攝像頭硬件可用，這些攝像頭型號均是1樣的，因此第1時間的想法是查看這些攝像機軟件版本或硬件固件版本是不是1致，答案是不是定的：
因此我又試了多個攝像機，只要是v2.0 build 100521 和v4.0 build 090220，這樣的都能顯示，但是其他的軟件版本都顯示不了。1時半會要更新軟件或固件版本也是1大工程，因此繼續查閱SDK開發文檔，發現其實可以查看裝備登錄預覽的SDK日志，在代碼中，只需在SDK初始化后調用NET_DVR_SetLogToFile()函數便可保存日志信息。啟用寫日志文件的函數定義以下：
BOOL NET_DVR_SetLogToFile(
DWORD nLogLevel, char *strLogDir, BOOL bAutoDel
);
其中，nLogLevel 表示日志的等級（默許為0）：0-表示關閉日志，1-表示只輸出ERROR毛病日志，2-輸出ERROR毛病信息和DEBUG調試信息，3-輸出ERROR毛病信息、DEBUG調試信息和INFO普通訊息等所有信息；
strLogDir 表示日志文件的路徑，windows默許值為”C:SdkLog”；linux默許值”/home/sdklog/”；
bAutoDel 表示是不是刪除超越的文件數，默許值為TRUE。
生成日志文件，發現實際上是缺少了必要的dll文件。
SDK V4.3.0.6
[2015⑴0⑵0 14:58:00.599][INF] version:This hcnetsdk version is 4.3.0.6 Version 2014_07_22.
SDK V4.3.0.6[2015⑴0⑵0 14:58:00.599][INF] LogonDev1 192.168.3.22:8000 in
[2015⑴0⑵0 14:58:00.601][INF] Private connect 192.168.3.22:8000 sock=496 this=0xf115e8 cmd=0x10000 port=30473
[2015⑴0⑵0 14:58:00.601][INF] OpenCommandConnection ptr=0xf115e8 id=4096
[2015⑴0⑵0 14:58:00.601][INF] [SendCommandWithRecv] this=0xf115e8, cmd_id=0x1000, cmd=0x10000
[2015⑴0⑵0 14:58:00.615][INF] [CloseCommandConnection] this=0xf115e8, cmd_id=0x1000
[2015⑴0⑵0 14:58:00.615][INF] StopLinkInConnection sock=496 this=0xf115e8, command=0x10000
[2015⑴0⑵0 14:58:00.620][INF] LogonDev1 192.168.3.22:8000 in
[2015⑴0⑵0 14:58:00.630][INF] Private connect 192.168.3.22:8000 sock=496 this=0xf115e8 cmd=0x10010 port=30474
[2015⑴0⑵0 14:58:00.630][INF] OpenCommandConnection ptr=0xf115e8 id=8192
[2015⑴0⑵0 14:58:00.630][INF] [SendCommandWithRecv] this=0xf115e8, cmd_id=0x2000, cmd=0x10010
[2015⑴0⑵0 14:58:00.631][DBG] MainStream 0xf0
[2015⑴0⑵0 14:58:00.631][INF] SubStream 0x0, RTP/RTSP[0], Private and RTSP[0], streamPacketType[0x0]
[2015⑴0⑵0 14:58:00.631][INF] [CloseCommandConnection] this=0xf115e8, cmd_id=0x2000
[2015⑴0⑵0 14:58:00.631][INF] StopLinkInConnection sock=496 this=0xf115e8, command=0x10010
[2015⑴0⑵0 14:58:00.636][INF] LogonDev1 192.168.3.22:8000 out, dev_ver=020220090317, protocol=0xf0f0 sn=DS2CD852MF-E0020100721BCCH401124400WC
[2015⑴0⑵0 14:58:00.636][INF] [UserCtrlInstance::AddUser] m_nCurrentUserIndex=0, i=0, m_nTotalUserNum=1
[2015⑴0⑵0 14:58:00.636][INF] Login success. UserID=0, DevIP=192.168.3.22
[2015⑴0⑵0 14:58:02.095][DBG] BaseEngine[class CNetPreviewSession / 1 / 1]::AllocSession[0] get instance[00F177C0]
[2015⑴0⑵0 14:58:02.095][INF] Preview Session=0 channel[1], UserID[0]
[2015⑴0⑵0 14:58:02.095][DBG] [0] userid[0] this[f177c0]PreviewStart in block[0] cbreal[13018cf]stand[0] userdatap[0] dw[0], hwnd[1905a2]
[2015⑴0⑵0 14:58:02.095][INF] StreamMode[0], StreamProtocol[0xf0f0]
[2015⑴0⑵0 14:58:02.095][DBG] [0] PreviewStart out
[2015⑴0⑵0 14:58:02.095][DBG] [0][192.168.3.22:8000]preview LinkToDvr
[2015⑴0⑵0 14:58:02.095][INF] StreamMode[0], StreamProtocol[0xf0f0]
[2015⑴0⑵0 14:58:02.125][ERR] GlobalCtrl load [E:Herbert Project單個攝像機解碼并顯示DebugStreamTransClient.dll] with sdk path failed and get handle[0]
[2015⑴0⑵0 14:58:02.129][ERR] Load StreamTransClient failed[syserr: 126]
[2015⑴0⑵0 14:58:02.129][ERR] Preview Session=0 link proto=4
[2015⑴0⑵0 14:58:02.129][ERR] [0] preview MainPreview link failed!!!
[2015⑴0⑵0 14:58:02.129][DBG] userid[0] Preview[0] AysoNonBlockThread callback exception
[2015⑴0⑵0 14:58:09.918][INF] [0]PreviewStop begin
[2015⑴0⑵0 14:58:09.918][DBG] [0] NetPreview SessionStop in, player nPort[⑴]
[2015⑴0⑵0 14:58:09.918][ERR] (IExchangeProxy::RigisterCommandIndex)this preview[0] is not registered.
[2015⑴0⑵0 14:58:09.918][DBG] [0] NetPreview SessionStop out
[2015⑴0⑵0 14:58:09.918][DBG] BaseEngine[class CNetPreviewSession / 512 / 1 / 1]::DestroySessionByIndex[0] instance[00F177C0]
[2015⑴0⑵0 14:58:12.274][DBG] FiniSDK begin SDK fini[1]
[2015⑴0⑵0 14:58:12.274][DBG] [0] DelUser CurrentUserIndex ⑴ total[0]
[2015⑴0⑵0 14:58:13.135][DBG] stop time thread
后面的操作就很簡單了，在海康的SDK庫文件中找到StreamTransClient.dll和SystemTransform.dll并添加到工程項目底下，問題解決。
3. 項目部份代碼
上傳時發現文件過大，因此只貼出部份代碼：
#include "stdafx.h" #include "SingleCamApp.h" #include "SingleCamDlg.h" #include "afxdialogex.h" #include "HCNetSDK.h" #include "plaympeg4.h" #ifdef _DEBUG #define new DEBUG_NEW #endif LONG nPort = -1;
HWND hPlayWnd = NULL; LONG lUserID = -1;
LONG lRealHandle = -1;
CString IPToStr(DWORD dwIP); void CALLBACK DecCBFun(long nPort,char * pBuf,long nSize,FRAME_INFO * pFrameInfo, long nReserved1,long nReserved2); void CALLBACK g_RealDataCallBack_V30(LONG lRealHandle, DWORD dwDataType, BYTE *pBuffer,DWORD dwBufSize,void* dwUser);
CSingleCamDlg::CSingleCamDlg(CWnd* pParent )
: CDialogEx(CSingleCamDlg::IDD, pParent)
{
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
} void CSingleCamDlg::DoDataExchange(CDataExchange* pDX)
{
CDialogEx::DoDataExchange(pDX);
DDX_Control(pDX, IDC_CAM_IP, m_ctrlDeviceIP); }
BEGIN_MESSAGE_MAP(CSingleCamDlg, CDialogEx)
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_BN_CLICKED(IDC_BTN_Login, &CSingleCamDlg::OnBnClickedBtnLogin)
ON_BN_CLICKED(IDC_BTN_PlayCam, &CSingleCamDlg::OnBnClickedBtnPlaycam)
ON_BN_CLICKED(IDC_BTN_StopCam, &CSingleCamDlg::OnBnClickedBtnStopcam)
END_MESSAGE_MAP()
BOOL CSingleCamDlg::OnInitDialog()
{
CDialogEx::OnInitDialog(); SetIcon(m_hIcon, TRUE); SetIcon(m_hIcon, FALSE); NET_DVR_Init();
isLogin = FALSE;
isPlaying = FALSE;
hPlayWnd = GetDlgItem(IDC_ViewWindow)->m_hWnd; m_ctrlDeviceIP.SetAddress(192, 168, 2, 21);
GetDlgItem(IDC_BTN_PlayCam)->EnableWindow(FALSE); GetDlgItem(IDC_BTN_StopCam)->EnableWindow(FALSE); return TRUE; } void CSingleCamDlg::OnPaint()
{ if (IsIconic())
{
CPaintDC dc(this); SendMessage(WM_ICONERASEBKGND, reinterpret_cast(dc.GetSafeHdc()), 0); int cxIcon = GetSystemMetrics(SM_CXICON); int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect); int x = (rect.Width() - cxIcon + 1) / 2; int y = (rect.Height() - cyIcon + 1) / 2; dc.DrawIcon(x, y, m_hIcon);
} else {
CDialogEx::OnPaint();
}
}
HCURSOR CSingleCamDlg::OnQueryDragIcon()
{ return static_cast(m_hIcon);
} CString IPToStr(DWORD dwIP)
{
CString strIP = _T("");
WORD add1,add2,add3,add4;
add1=(WORD)(dwIP&255);
add2=(WORD)((dwIP>>8)&255);
add3=(WORD)((dwIP>>16)&255);
add4=(WORD)((dwIP>>24)&255);
strIP.Format("%d.%d.%d.%d",add4,add3,add2,add1); return strIP;
} void CALLBACK g_RealDataCallBack_V30(LONG lRealHandle, DWORD dwDataType, BYTE *pBuffer,DWORD dwBufSize,void* dwUser)
{ switch (dwDataType)
{ case NET_DVR_SYSHEAD: if (!PlayM4_GetPort(&nPort)) { break;
} if (dwBufSize > 0)
{ if (!PlayM4_SetStreamOpenMode(nPort, STREAME_REALTIME)) { break;
} if (!PlayM4_OpenStream(nPort, pBuffer, dwBufSize, 1024*1024)) { break;
} if (!PlayM4_SetDecCallBackEx(nPort,DecCBFun,NULL,NULL))
{ break;
} if (!PlayM4_SetDisplayBuf(nPort, 4)) { break;
} if (!PlayM4_Play(nPort,hPlayWnd)) { break;
}
} case NET_DVR_STREAMDATA: if (dwBufSize > 0 && nPort != -1) if (!PlayM4_InputData(nPort, pBuffer, dwBufSize)) break;
}
} void CALLBACK DecCBFun(long nPort,char * pBuf,long nSize,FRAME_INFO * pFrameInfo, long nReserved1,long nReserved2)
{
} void CSingleCamDlg::OnBnClickedBtnLogin() { if (isLogin) {
NET_DVR_Logout(lUserID);
isLogin = FALSE;
GetDlgItem(IDC_BTN_Login)->SetWindowTextA("登錄");
GetDlgItem(IDC_BTN_PlayCam)->EnableWindow(FALSE); } else { char DeviceIP[16] = {0};
DWORD dwDeviceIP = 0;
m_ctrlDeviceIP.GetAddress(dwDeviceIP);
CString csTemp = IPToStr(dwDeviceIP);
sprintf_s(DeviceIP, "%s", csTemp.GetBuffer(0));
NET_DVR_DEVICEINFO_V30 struDeviceInfo;
lUserID = NET_DVR_Login_V30(DeviceIP, 8000, "admin", "12345", &struDeviceInfo); if (lUserID < 0) {
AfxMessageBox("登錄失敗!");
isLogin = FALSE;
} else {
isLogin = TRUE;
GetDlgItem(IDC_BTN_Login)->SetWindowTextA("注銷"); GetDlgItem(IDC_BTN_PlayCam)->EnableWindow(TRUE); }
}
} void CSingleCamDlg::OnBnClickedBtnPlaycam() {
NET_DVR_PREVIEWINFO struPlayInfo = {0};
struPlayInfo.hPlayWnd = NULL; struPlayInfo.lChannel = 1; struPlayInfo.dwStreamType = 0; struPlayInfo.dwLinkMode = 0; lRealHandle = NET_DVR_RealPlay_V40(lUserID, &struPlayInfo, g_RealDataCallBack_V30, NULL); if (lRealHandle < 0)
{
AfxMessageBox("播放失敗!");
isPlaying = FALSE; } else {
GetDlgItem(IDC_BTN_Login)->EnableWindow(FALSE); GetDlgItem(IDC_BTN_PlayCam)->EnableWindow(FALSE); GetDlgItem(IDC_BTN_StopCam)->EnableWindow(TRUE); isPlaying = TRUE;
}
} void CSingleCamDlg::OnBnClickedBtnStopcam() {
NET_DVR_StopRealPlay(lRealHandle); PlayM4_Stop(nPort);
PlayM4_CloseStream(nPort);
PlayM4_FreePort(nPort);
GetDlgItem(IDC_BTN_Login)->EnableWindow(TRUE); GetDlgItem(IDC_BTN_PlayCam)->EnableWindow(TRUE); GetDlgItem(IDC_BTN_StopCam)->EnableWindow(FALSE); }
