昨晚跑了3520D的sample_vio程序,遇到几个困惑点,跟大家探讨下

先上代码:
HI_S32 SAMPLE_VIO_4_D1(HI_VOID)
{
    SAMPLE_VI_MODE_E enViMode = SAMPLE_VI_MODE_4_D1;

    HI_U32 u32ViChnCnt = 4;
    HI_S32 s32VpssGrpCnt = 4;
   
    VB_CONF_S stVbConf;
    VI_CHN ViChn;
    VPSS_GRP VpssGrp;
    VPSS_GRP_ATTR_S stGrpAttr;
    VPSS_CHN VpssChn_VoHD0 = VPSS_PRE0_CHN;
    VO_DEV VoDev;
    VO_CHN VoChn;
    VO_PUB_ATTR_S stVoPubAttr,stVoPubAttrSD;
    SAMPLE_VO_MODE_E enVoMode, enPreVoMode;
   
    HI_S32 i;
    HI_S32 s32Ret = HI_SUCCESS;
    HI_U32 u32BlkSize;
    HI_CHAR ch;
    SIZE_S stSize;
    HI_U32 u32WndNum;
       
        VO_WBC_ATTR_S stWbcAttr;

    /******************************************
     step  1: init variable
    ******************************************/
    gs_u32ViFrmRate = (VIDEO_ENCODING_MODE_PAL== gs_enNorm)?25:30;
   
    memset(&stVbConf,0,sizeof(VB_CONF_S));

    u32BlkSize = SAMPLE_COMM_SYS_CalcPicVbBlkSize(gs_enNorm,\
                PIC_D1, SAMPLE_PIXEL_FORMAT, SAMPLE_SYS_ALIGN_WIDTH);
    stVbConf.u32MaxPoolCnt = 128;

    /* video buffer*/
    //todo: vb=15
        stVbConf.astCommPool[0].u32BlkSize = u32BlkSize;
    stVbConf.astCommPool[0].u32BlkCnt = u32ViChnCnt * 8;

       
    /******************************************
     step 2: mpp system init.
    ******************************************/
    s32Ret = SAMPLE_COMM_SYS_Init(&stVbConf);
    if (HI_SUCCESS != s32Ret)
    {
        SAMPLE_PRT("system init failed with %d!\n", s32Ret);
        goto END_8D1_0;
    }

    /******************************************
     step 3: start vi dev & chn
    ******************************************/
    s32Ret = SAMPLE_COMM_VI_Start(enViMode, gs_enNorm);
    if (HI_SUCCESS != s32Ret)
    {
        SAMPLE_PRT("start vi failed!\n");
        goto END_8D1_0;
    }

    /******************************************
     step 4: start vpss and vi bind vpss
    ******************************************/
    s32Ret = SAMPLE_COMM_SYS_GetPicSize(gs_enNorm, PIC_D1, &stSize);
    if (HI_SUCCESS != s32Ret)
    {
        SAMPLE_PRT("SAMPLE_COMM_SYS_GetPicSize failed!\n");
        goto END_8D1_0;
    }
   
    stGrpAttr.u32MaxW = stSize.u32Width;
    stGrpAttr.u32MaxH = stSize.u32Height;
    stGrpAttr.bDrEn = HI_FALSE;
    stGrpAttr.bDbEn = HI_FALSE;
    stGrpAttr.bIeEn = HI_TRUE;
    stGrpAttr.bNrEn = HI_TRUE;
    stGrpAttr.bHistEn = HI_FALSE;
    stGrpAttr.enDieMode = VPSS_DIE_MODE_AUTO;
    stGrpAttr.enPixFmt = SAMPLE_PIXEL_FORMAT;

    s32Ret = SAMPLE_COMM_VPSS_Start(s32VpssGrpCnt, &stSize, VPSS_MAX_CHN_NUM,NULL);
    if (HI_SUCCESS != s32Ret)
    {
        SAMPLE_PRT("Start Vpss failed!\n");
        goto END_8D1_1;
    }

    s32Ret = SAMPLE_COMM_VI_BindVpss(enViMode);
    if (HI_SUCCESS != s32Ret)
    {
        SAMPLE_PRT("Vi bind Vpss failed!\n");
        goto END_8D1_2;
    }

    /******************************************
     step 6: start vo HD0 (HDMI+VGA), multi-screen, you can switch mode
    ******************************************/
    printf("start vo HD0.\n");
    //HI3520D¸高清输出设备只有一个DHD0
    VoDev = SAMPLE_VO_DEV_DHD0;
    u32WndNum = 4;
    enVoMode = VO_MODE_4MUX;
   
    if(VIDEO_ENCODING_MODE_PAL == gs_enNorm)
    {
        stVoPubAttr.enIntfSync = VO_OUTPUT_1024x768_60;
    }
    else
    {
        stVoPubAttr.enIntfSync = VO_OUTPUT_1024x768_60;
    }
        //HI_FPGA 未定义
#ifdef HI_FPGA
        stVoPubAttr.enIntfType = VO_INTF_HDMI|VO_INTF_VGA|VO_INTF_BT1120;
#else
        stVoPubAttr.enIntfType = VO_INTF_HDMI|VO_INTF_VGA;
#endif

    stVoPubAttr.u32BgColor = 0x000000ff;
    stVoPubAttr.bDoubleFrame = HI_TRUE;
   
    s32Ret = SAMPLE_COMM_VO_StartDevLayer(VoDev, &stVoPubAttr, gs_u32ViFrmRate);
    if (HI_SUCCESS != s32Ret)
    {
        SAMPLE_PRT("Start SAMPLE_COMM_VO_StartDevLayer failed!\n");
        goto END_8D1_4;
    }
    //启动每个指定的视频输出通道VoDev=SAMPLE_VO_DEV_DHD0
    s32Ret = SAMPLE_COMM_VO_StartChn(VoDev, &stVoPubAttr, enVoMode);
    if (HI_SUCCESS != s32Ret)
    {
        SAMPLE_PRT("Start SAMPLE_COMM_VO_StartChn failed!\n");
        goto END_8D1_5;
    }

    /* if it's displayed on HDMI, we should start HDMI */
    if (stVoPubAttr.enIntfType & VO_INTF_HDMI)
    {
        if (HI_SUCCESS != SAMPLE_COMM_VO_HdmiStart(stVoPubAttr.enIntfSync))
        {
            SAMPLE_PRT("Start SAMPLE_COMM_VO_HdmiStart failed!\n");
            goto END_8D1_5;
        }
    }
   
    for(i=0;i     {
        VoChn = i;
        VpssGrp = i;        
        s32Ret = SAMPLE_COMM_VO_BindVpss(VoDev,VoChn,VpssGrp,VpssChn_VoHD0);
        if (HI_SUCCESS != s32Ret)
        {
            SAMPLE_PRT("Start VO failed!\n");
            goto END_8D1_5;
        }
    }
       
#if 1
        /******************************************
        step 7: start vo SD0 (CVBS) (WBC target)
        ******************************************/
        printf("start vo SD0: wbc from hd0\n");
        VoDev = SAMPLE_VO_DEV_DSD1;//这里如果使用SAMPLE_VO_DEV_DSD0不行,CVBS无视频输出
        u32WndNum = 1;
        enVoMode = VO_MODE_1MUX;

        stVoPubAttrSD.enIntfSync = VO_OUTPUT_PAL;
        stVoPubAttrSD.enIntfType = VO_INTF_CVBS;
        stVoPubAttrSD.u32BgColor = 0x000000ff;
        stVoPubAttrSD.bDoubleFrame = HI_FALSE;
        s32Ret = SAMPLE_COMM_VO_StartDevLayer(VoDev, &stVoPubAttrSD, gs_u32ViFrmRate);
        if (HI_SUCCESS != s32Ret)
        {
                  SAMPLE_PRT("SAMPLE_COMM_VO_StartDevLayer failed!\n");
                  goto END_8D1_5;
        }
    ///启动输出设备VoDev(SAMPLE_VO_DEV_DSD1) 的所有通道
  //因为enVoMode==VO_MODE_1MUX,实际只启动一个输出通道(通道0)
        s32Ret = SAMPLE_COMM_VO_StartChn(VoDev, &stVoPubAttrSD, enVoMode);
        if (HI_SUCCESS != s32Ret)
        {
                  SAMPLE_PRT("SAMPLE_COMM_VO_StartChn failed!\n");
                  goto END_8D1_6;
        }
          
        s32Ret = SAMPLE_COMM_VO_GetWH(VO_OUTPUT_PAL, \
                                          &stWbcAttr.stTargetSize.u32Width, \
                                          &stWbcAttr.stTargetSize.u32Height, \
                                          &stWbcAttr.u32FrameRate);
        if (HI_SUCCESS != s32Ret)
        {
                SAMPLE_PRT("SAMPLE_COMM_VO_GetWH failed!\n");
                goto END_8D1_6;
        }
        stWbcAttr.enPixelFormat = SAMPLE_PIXEL_FORMAT;
    stWbcAttr.enDataSource = VO_WBC_DATASOURCE_MIXER;
        /*
        对高清输出设备SAMPLE_VO_DEV_DHD0 进行视频回写,设置回写参数
        */
        s32Ret = HI_MPI_VO_SetWbcAttr(SAMPLE_VO_DEV_DHD0, &stWbcAttr);
        if (HI_SUCCESS != s32Ret)
        {
                SAMPLE_PRT("HI_MPI_VO_SetWbcAttr failed!\n");
                goto END_8D1_6;
        }

        s32Ret = HI_MPI_VO_EnableWbc(SAMPLE_VO_DEV_DHD0);
        if (HI_SUCCESS != s32Ret)
        {
                SAMPLE_PRT("HI_MPI_VO_SetWbcAttr failed!\n");
                goto END_8D1_7;
        }
        ///以高清输出设备SAMPLE_VO_DEV_DHD0的通道0作为视频源
        ///标清输出设备VoDev(SAMPLE_VO_DEV_DSD1)的通道0作为目标进行视频回写
        s32Ret = SAMPLE_COMM_VO_BindVoWbc(SAMPLE_VO_DEV_DHD0, VoDev, 0);
        if (HI_SUCCESS != s32Ret)
        {
                SAMPLE_PRT("HI_MPI_VO_SetWbcAttr failed!\n");
                goto END_8D1_7;
        }
#endif

while(1)sleep(1);/////到这一步就可以在显示器的看到VGA,HDMI,以及CVBS视频了

后面的代码省略
....

}

跟我的困惑可能有相关的部分注释我已经在代码中标识了出来
下面说下我的几点困惑:
1.在这个例子中,VGA.HDMI,以及CVBS都有输出的,其中CVBS接的显示器上的AV接口,显示器有AV1和AV2两个,
        按理说不是应该只有一个AV显示吗,这里标清输出设备用的是SAMPLE_VO_DEV_DSD1,我觉得应该显示器AV2有视频才对,至少不应该AV1.AV2两个都有视频吧?
        当然这里的CVBS输出的是高清设备0的视频回写
2.标清输出设备SAMPLE_VO_DEV_DSD1 ,enVoMode = VO_MODE_1MUX不是应该只输出一路(1个窗口)吗?为什么我测试的时候显示有4个窗口.
3.step7,VoDev = SAMPLE_VO_DEV_DSD1换成VoDev = SAMPLE_VO_DEV_DSD0后,显示器AV口不再显示视频,为什么?

望大家互相讨论,不吝赐教,上面哪里说的不对欢迎指正.