这个SDK里面有一个三路编码h264的流，另外一个是JPEG抓拍的。

虽然文档里面建议通道0进行抓拍，SDK用的通道1. 将其入到三路码流之后。通道3。

开始一直错误，VpssChn = 3;没有设定，设定如下：

//抓拍的通道       获取图像'小		s32Ret = SAMPLE_COMM_SYS_GetPicSize(gs_enNorm, enSize[0], &stSize);	    if (HI_SUCCESS != s32Ret)	    {	        SAMPLE_PRT("SAMPLE_COMM_SYS_GetPicSize failed!\n");	        goto END_VENC_1080P_CLASSIC_4;	    }		VpssChn = 3;		stVpssChnMode.enChnMode 	= VPSS_CHN_MODE_USER;		stVpssChnMode.bDouble		= HI_FALSE;		stVpssChnMode.enPixelFormat = PIXEL_FORMAT_YUV_SEMIPLANAR_420;		stVpssChnMode.u32Width		= stSize.u32Width;		stVpssChnMode.u32Height 	= stSize.u32Height;		stVpssChnMode.enCompressMode = COMPRESS_MODE_NONE;		memset(&stVpssChnAttr, 0, sizeof(stVpssChnAttr));		stVpssChnAttr.s32SrcFrameRate = -1;		stVpssChnAttr.s32DstFrameRate = -1;				s32Ret = SAMPLE_COMM_VPSS_EnableChn(VpssGrp, VpssChn, &stVpssChnAttr, &stVpssChnMode, HI_NULL);		if (HI_SUCCESS != s32Ret)		{			SAMPLE_PRT("Enable vpss chn failed!\n");			goto END_VENC_1080P_CLASSIC_4;		}

　之后就是绑定和获取图片

//hg 添加拍照功能 2018-12-24	VpssGrp = 0;    VpssChn = 3;    VencChn = 3;	s32Ret = SAMPLE_COMM_VENC_SnapStart(VpssChn,&stSize,HI_FALSE);	if(HI_SUCCESS !=s32Ret)	{		SAMPLE_PRT("Start snap failed!\n");		goto END_VENC_JPEG_6;	}	s32Ret = SAMPLE_COMM_VENC_BindVpss(VencChn, VpssGrp, VpssChn);	if (HI_SUCCESS != s32Ret)    {        SAMPLE_PRT("Start Venc failed!\n");        goto END_VENC_JPEG_6;    }

　　三个图可以直观的观察vpss: