简述

  使用海康摄像头采集图像时，需要在图像上添加图标、文字等额外数据。可选择使用海康SDK绘图回调函数叠加字符、图像等（请参考上一篇文章）；也可使用海康SDK的解码回调函数，对视频流数据进行解码后处理。该方法流程为：调用视频预览函数NET_DVR_RealPlay_V40()时将第三个参数设置为实时数据回调函数RealDataCallBack()的函数指针，然后在RealDataCallBack()回调函数中注册视频流数据解码函数DecCallbackFUN()，最后在DecCallbackFUN()函数中对数据解析解码、叠加字符等处理。
  本文只调用解码回调函数将YV12格式视频流数据转换为RGB32格式数据，然后将RGB32格式数据转换为Image，并使用PictrueBox显示该Image数据，暂不做叠加字符、图像等处理。

代码

1、摄像头操作代码

    struct CameraInfo{public string strIP;public short nPort;public string strUserName;public string strPassword;}class IDeviceCamera{public Image m_img = null;public virtual bool InitCamera( CameraInfo stInfo ){return true;}}class DeviceCamera : IDeviceCamera{private CameraInfo m_stCameraInfo;private bool m_bInitSDK = false;private Int32 m_lUserID = -1;private Int32 m_lRealHandle = -1;private Int32 m_lPort = -1;CHCNetSDK.REALDATACALLBACK RealData = null; //必须得定义为成员变量public override bool InitCamera( CameraInfo stInfo ){m_stCameraInfo = stInfo;m_bInitSDK = CHCNetSDK.NET_DVR_Init();if ( !m_bInitSDK ){uint nError = CHCNetSDK.NET_DVR_GetLastError();}CHCNetSDK.NET_DVR_SetConnectTime( 5000, 1 );CHCNetSDK.NET_DVR_SetReconnect( 10000, 1 );if ( m_bInitSDK == false ){MessageBox.Show( "NET_DVR_Init error!" );return false;}else{//保存SDK日志 To save the SDK logCHCNetSDK.NET_DVR_SetLogToFile( 3, "C:\\SdkLog\\", true );}string DVRIPAddress = stInfo.strIP;     //设备IP地址或者域名 Device IPInt16 DVRPortNumber = stInfo.nPort;     //设备服务端口号 Device Portstring DVRUserName = stInfo.strUserName;//设备登录用户名 User name to loginstring DVRPassword = stInfo.strPassword;//设备登录密码 Password to loginCHCNetSDK.NET_DVR_DEVICEINFO_V30 DeviceInfo = new CHCNetSDK.NET_DVR_DEVICEINFO_V30();m_lUserID = CHCNetSDK.NET_DVR_Login_V30( DVRIPAddress, DVRPortNumber, DVRUserName, DVRPassword, ref DeviceInfo );if ( m_lUserID < 0 ){MessageBox.Show( "登录失败！" );CHCNetSDK.NET_DVR_Cleanup();return false;}//CHCNetSDK.NET_DVR_PREVIEWINFO lpPreviewInfo = new CHCNetSDK.NET_DVR_PREVIEWINFO();lpPreviewInfo.hPlayWnd = (IntPtr)null;lpPreviewInfo.lChannel = 1;lpPreviewInfo.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lpPreviewInfo.dwLinkMode = 0;         //连接方式：0- TCP方式，1- UDP方式，2- 多播方式，3- RTP方式，4-RTP/RTSP，5-RSTP/HTTP lpPreviewInfo.bBlocked = true;        //0- 非阻塞取流，1- 阻塞取流lpPreviewInfo.dwDisplayBufNum = 15;   //播放库播放缓冲区最大缓冲帧数//使用回调函数取摄像头数据RealData = new CHCNetSDK.REALDATACALLBACK( RealDataCallBack );//预览实时流回调函数IntPtr pUser = new IntPtr();//用户数据m_lRealHandle = CHCNetSDK.NET_DVR_RealPlay_V40( m_lUserID, ref lpPreviewInfo, RealData, pUser );CHCNetSDK.NET_DVR_RigisterDrawFun( m_lRealHandle, new CHCNetSDK.DRAWFUN( cbDrawFun ), 0 );//回调函数：绘制图标return true;}private uint nLastErr = 0;private static PlayCtrl.DECCBFUN m_fDisplayFun = null;private IntPtr m_ptrRealHandle;public void RealDataCallBack( Int32 lRealHandle, UInt32 dwDataType, IntPtr pBuffer, UInt32 dwBufSize, IntPtr pUser ){//下面数据处理建议使用委托的方式switch ( dwDataType ){case CHCNetSDK.NET_DVR_SYSHEAD:     // sys headif ( dwBufSize > 0 ){if ( m_lPort >= 0 )return; //同一路码流不需要多次调用开流接口//获取播放句柄 Get the port to playif ( !PlayCtrl.PlayM4_GetPort( ref m_lPort ) ){nLastErr = PlayCtrl.PlayM4_GetLastError( m_lPort );break;}//设置流播放模式 Set the stream mode: real-time stream modeif ( !PlayCtrl.PlayM4_SetStreamOpenMode( m_lPort, PlayCtrl.STREAME_REALTIME ) ){nLastErr = PlayCtrl.PlayM4_GetLastError( m_lPort );//str = "Set STREAME_REALTIME mode failed, error code= " + nLastErr;//this.BeginInvoke( AlarmInfo, str );}//打开码流，送入头数据 Open streamif ( !PlayCtrl.PlayM4_OpenStream( m_lPort, pBuffer, dwBufSize, 2 * 1024 * 1024 ) ){nLastErr = PlayCtrl.PlayM4_GetLastError( m_lPort );//str = "PlayM4_OpenStream failed, error code= " + nLastErr;//this.BeginInvoke( AlarmInfo, str );break;}//设置显示缓冲区个数 Set the display buffer numberif ( !PlayCtrl.PlayM4_SetDisplayBuf( m_lPort, 15 ) ){nLastErr = PlayCtrl.PlayM4_GetLastError( m_lPort );//str = "PlayM4_SetDisplayBuf failed, error code= " + nLastErr;//this.BeginInvoke( AlarmInfo, str );}//设置显示模式 Set the display mode//if ( !PlayCtrl.PlayM4_SetOverlayMode( m_lPort, 0, 0) ) //play off screen //{//    nLastErr = PlayCtrl.PlayM4_GetLastError( m_lPort );//    //str = "PlayM4_SetOverlayMode failed, error code= " + nLastErr;//    //this.BeginInvoke( AlarmInfo, str );//}//设置解码回调函数，获取解码后音视频原始数据 Set callback function of decoded datam_fDisplayFun = new PlayCtrl.DECCBFUN( DecCallbackFUN );if ( !PlayCtrl.PlayM4_SetDecCallBackEx( m_lPort, m_fDisplayFun, IntPtr.Zero, 0 ) ){//this.BeginInvoke( AlarmInfo, "PlayM4_SetDisplayCallBack fail" );}//开始解码 Start to play                       if ( !PlayCtrl.PlayM4_Play( m_lPort, m_ptrRealHandle ) ){nLastErr = PlayCtrl.PlayM4_GetLastError( m_lPort );//str = "PlayM4_Play failed, error code= " + nLastErr;//this.BeginInvoke( AlarmInfo, str );break;}}break;case CHCNetSDK.NET_DVR_STREAMDATA: // video stream datadefault: //the other dataif ( dwBufSize > 0 && m_lPort != -1 ){for ( int i = 0; i < 999; i++ ){//送入码流数据进行解码 Input the stream data to decodeif ( !PlayCtrl.PlayM4_InputData( m_lPort, pBuffer, dwBufSize ) ){nLastErr = PlayCtrl.PlayM4_GetLastError( m_lPort );//str = "PlayM4_InputData failed, error code= " + nLastErr;Thread.Sleep( 2 );}elsebreak;}}break;}}//解码回调函数private void DecCallbackFUN( int nPort, IntPtr pBuf, int nSize, ref PlayCtrl.FRAME_INFO pFrameInfo, int nReserved1, int nReserved2 ){if ( pFrameInfo.nType == 3 ) //#define T_YV12   3{byte[] byteBuffYV12 = new byte[ nSize ];Marshal.Copy( pBuf, byteBuffYV12, 0, nSize );long lRGBSize = (long)pFrameInfo.nWidth * pFrameInfo.nHeight * 4;byte[] bufferRGB32 = new byte[ lRGBSize ];CommonFun.YV12_to_RGB32( byteBuffYV12, bufferRGB32, pFrameInfo.nWidth, pFrameInfo.nHeight );byteBuffYV12 = null;Bitmap bmpFromGRB32 = CommonFun.RGB32_to_Image( bufferRGB32, pFrameInfo.nWidth, pFrameInfo.nHeight );bufferRGB32 = null;if ( null == bmpFromGRB32 )return;m_img = bmpFromGRB32;}}}

注：得到的m_img用于PictureBox进行显示。

2、YV12转换为RGB32、RGB32转换为Image代码

class CommonFun{public static bool YV12_to_RGB32(  byte[] buffYV12, byte[] bufferRGB32, int nWidth, int nHeight ){if( buffYV12.Length < 0 || bufferRGB32.Length < 0 )return false;long nYLen = (long)nWidth * nHeight;int nHfWidth = ( nWidth >> 1 );if ( nYLen < 1 || nHfWidth < 1 )return false;byte[] byteYData = buffYV12.Skip( 0 ).Take( nWidth*nHeight ).ToArray();byte[] byteUData = buffYV12.Skip( nWidth*nHeight ).Take( (nHeight/2)*(nWidth/2) ).ToArray();byte[] byteVData = buffYV12.Skip( nWidth*nHeight + (nHeight/2)*(nWidth/2) ).Take( (nHeight/2)*(nWidth/2) ).ToArray();if ( byteYData.Length < 0 || byteVData.Length < 0 || byteUData.Length < 0 )return false;int[] nRgb = new int[4];for( int nRow = 0; nRow < nHeight; nRow++ ){for( int nCol = 0; nCol < nWidth; nCol++ ){int Y = byteYData[nRow*nWidth + nCol];int U = byteUData[(nRow / 2)*(nWidth / 2) + (nCol / 2)];int V = byteVData[(nRow / 2)*(nWidth / 2) + (nCol / 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;nRgb[2] = R > 255 ? 255 : R;// g分量值G = G<0 ? 0 : G;nRgb[1] = G > 255 ? 255 : G;// b分量值 B = B<0 ? 0 : B;nRgb[0] = B > 255 ? 255 : B;//A分量值nRgb[ 3 ] = 255;//Out RGB BufferbufferRGB32[4 * (nRow*nWidth + nCol) + 0] = (byte)nRgb[0];bufferRGB32[4 * (nRow*nWidth + nCol) + 1] = (byte)nRgb[1];bufferRGB32[4 * (nRow*nWidth + nCol) + 2] = (byte)nRgb[2];bufferRGB32[4 * (nRow*nWidth + nCol) + 3] = (byte)nRgb[3];}}return true;}public static Bitmap RGB32_to_Image( byte[] byteBuff, int nWidth, int nHeight ){if ( byteBuff.Length <= 0 || byteBuff.Length < nWidth*nHeight )return null;Bitmap bmp = new Bitmap( nWidth, nHeight, PixelFormat.Format32bppArgb );//锁定内存数据BitmapData bmpData = bmp.LockBits( new Rectangle( 0, 0, nWidth, nHeight ), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb );//输入颜色数据System.Runtime.InteropServices.Marshal.Copy( byteBuff, 0, bmpData.Scan0, byteBuff.Length );//解锁bmp.UnlockBits( bmpData );return bmp;}}

效果