How can i use custream in cuvidMapVideoFrame

Gaming and Visualization Technologies Video Processing & Optical Flow
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1

hi,i hope someone can help me.
I am using NvDecoder to decode multiple videos.follow the sample i have finished my job.
but now i want to improve performance.
when i saw the following codes

     int NvDecoder::HandlePictureDisplay(CUVIDPARSERDISPINFO *pDispInfo) {
		CUVIDPROCPARAMS videoProcessingParameters = {};
		videoProcessingParameters.progressive_frame = pDispInfo->progressive_frame;
		videoProcessingParameters.second_field = pDispInfo->repeat_first_field + 1;
		videoProcessingParameters.top_field_first = pDispInfo->top_field_first;
		videoProcessingParameters.unpaired_field = pDispInfo->repeat_first_field < 0;
		videoProcessingParameters.output_stream = m_cuvidStream;

		CUdeviceptr dpSrcFrame = 0;
		unsigned int nSrcPitch = 0;
		CUDA_DRVAPI_CALL(cuCtxPushCurrent(m_cuContext));
		NVDEC_API_CALL(cuvidMapVideoFrame(m_hDecoder, pDispInfo->picture_index, &dpSrcFrame,
			&nSrcPitch, &videoProcessingParameters));
			
			..............
		}
			
	I realised that i can use 'CUstream' to get a perfect result of parallel execution in cuda.
    So i create a custream by 'cuStreamCreate(&custream,0)' outside.then use it as followed.
	
	int NvDecoder::Decode(const uint8_t *pData, int nSize, int nFlags, int64_t nTimestamp ,Custream custream)
	{
	    ............
	    NVDEC_API_CALL(cuvidParseVideoData(m_hParser, &packet));
		//m_cuvidStream = 0;  //sample default 0
		m_cuvidStream=custream;
		........
	}

Now i get a mistake :
‘cuvidMapVideoFrame(m_hDecoder, pDispInfo->picture_index, &dpSrcFrame, &nSrcPitch, &videoProcessingParameters) returned error 400’
what i can do to solve this problem, cuvidMapVideoFrame can not use CUstream?