代码框架：

SAMPLE_VENC_720P_CLASSIC
  SAMPLE_RGN_CreateVideoRegion//用图片的方式创建所有区域
    SAMPLE_RGN_CreateOverlayForVenc//左下角的区域
      HI_MPI_RGN_Create
      HI_MPI_RGN_AttachToChn
    SAMPLE_RGN_Add
      HI_MPI_RGN_GetAttr
      HI_MPI_RGN_GetCanvasInfo
      SAMPLE_RGN_UpdateCanvas
        SAMPLE_RGN_CreateSurfaceByCanvas
          SAMPLE_RGN_LoadCanvasEx
            SAMPLE_RGN_LoadBMPCanvas_Logo  //if(Type == VENC_RECORD_LOGO_OSD_HANDLE)
            SAMPLE_RGN_LoadBMPCanvas_TimeSmap//else
              SAMPLE_RGN_GetBMPSrc  //得到文件名
      HI_MPI_RGN_UpdateCanvas
    SAMPLE_RGN_CreateOverlayForVenc//右下角的区域
      HI_MPI_RGN_Create
      HI_MPI_RGN_AttachToChn
      
    pthread_create(&osd_ThreadId, NULL, SAMPLE_RGN_AddVideoTimestamp, NULL);
      SAMPLE_RGN_Add
        HI_MPI_RGN_GetAttr
        HI_MPI_RGN_GetCanvasInfo
        SAMPLE_RGN_UpdateCanvas
          SAMPLE_RGN_CreateSurfaceByCanvas
              SAMPLE_RGN_LoadCanvasEx
              SAMPLE_RGN_LoadBMPCanvas_Logo  //if(Type == VENC_RECORD_LOGO_OSD_HANDLE)
              SAMPLE_RGN_LoadBMPCanvas_TimeSmap//else
              SAMPLE_RGN_GetBMPSrc
        HI_MPI_RGN_UpdateCanvas
  //用字库的方式创建所有区域
  HH_OSD_Init
    HH_OSD_SetOsdPosDefault
    HH_OSD_GetOrg
    HH_OSD_GetColor
    HH_OSD_GetTitle
      HH_OSD_GetTimeTitle//if (nOsdType == HH_OSD_TYPE_TIME)
      HH_OSD_GetChNameTitleelse// if (nOsdType == HH_OSD_TYPE_TITLE)
    HI_Create_Osd
      HI_OSD_Build
        HI_OSD_Parse_OsdTitle
        HI_OSD_Get_BmpSize
          HI_OSD_Get_ImaSize
        HI_Create_Osd_Reg//创建区域
          HI_MPI_RGN_Create
          HI_MPI_RGN_AttachToChn
        HI_OSD_Create_Bitmap//创建bmp
          HI_OSD_CreateBMP
            HI_OSD_GetCharBit
            HI_OSD_DrawBitmapBit32//if 将汉字的点阵转换为bmp写入缓冲区
            HI_OSD_DrawBitmapBit//else 将汉字的点阵转换为bmp写入缓冲区
          HI_MPI_RGN_SetBitMap
        HI_OSD_Set_Show//显示OSD
          HI_MPI_RGN_GetDisplayAttr
          HI_MPI_RGN_SetDisplayAttr
  

  HH_OSD_All_Refresh
    HH_OSD_AllTime_Refresh//时间osd
      HH_OSD_ChnTime_Refresh
        HH_OSD_ChName_Refresh
          HH_OSD_GetLogoHandle
          HH_OSD_GetTitle
            HH_OSD_GetTimeTitle//if (nOsdType == HH_OSD_TYPE_TIME)
            HH_OSD_GetChNameTitleelse// if (nOsdType == HH_OSD_TYPE_TITLE)
          HI_OSD_Check_ImaSizeChange
            HI_OSD_Get_ImaSize
          HI_OSD_Parse_OsdTitle
          HI_OSD_Get_BmpSize
          //if 要销毁
            HI_OSD_Destroy
              HI_MPI_RGN_Destroy
            HI_Create_Osd_Reg
              HI_MPI_RGN_Create
              HI_MPI_RGN_AttachToChn
            HI_OSD_Refresh_Org
              HI_MPI_RGN_GetDisplayAttr
              HI_MPI_RGN_SetDisplayAttr
          HI_OSD_Create_Bitmap
            HI_OSD_CreateBMP
              HI_OSD_GetCharBit
              HI_OSD_DrawBitmapBit32//if 将汉字的点阵转换为bmp写入缓冲区
              HI_OSD_DrawBitmapBit//else 将汉字的点阵转换为bmp写入缓冲区
            HI_MPI_RGN_SetBitMap
          HH_OSD_Show_Refresh
            HH_OSD_GetLogoHandle
            HH_OSD_GetShow
            HI_OSD_Set_Show
              HI_MPI_RGN_GetDisplayAttr
              HI_MPI_RGN_SetDisplayAttr
          
    HH_OSD_AllName_Refresh//姓名osd
      HH_OSD_ChnAllName_Refresh
        HH_OSD_ChName_Refresh