Get wrong infer results while testing yolov4 on deepstream 5.0

Accelerated Computing Intelligent Video Analytics DeepStream SDK
44

Hi I followed the instructions DeepStream SDK FAQ - #7 by bcao
and it seams to run somehow.
But I dont get any visual output.

Unknown or legacy key specified 'is-classifier' for group [property]
Opening in BLOCKING MODE 
0:00:03.976461743   698     0x26425b60 INFO                 nvinfer gstnvinfer.cpp:619:gst_nvinfer_logger:<primary_gie> NvDsInferContext[UID 1]: Info from NvDsInferContextImpl::deserializeEngineAndBackend() <nvdsinfer_context_impl.cpp:1701> [UID = 1]: deserialized trt engine from :/xavier_ssd/deepstream/deepstream-5.0/sources/objectDetector_Yolo/yolov4_1_3_608_608_fp16.engine
INFO: [Implicit Engine Info]: layers num: 3
0   INPUT  kFLOAT input           3x608x608       
1   OUTPUT kFLOAT boxes           22743x1x4       
2   OUTPUT kFLOAT confs           22743x80        

0:00:03.976671001   698     0x26425b60 INFO                 nvinfer gstnvinfer.cpp:619:gst_nvinfer_logger:<primary_gie> NvDsInferContext[UID 1]: Info from NvDsInferContextImpl::generateBackendContext() <nvdsinfer_context_impl.cpp:1805> [UID = 1]: Use deserialized engine model: /xavier_ssd/deepstream/deepstream-5.0/sources/objectDetector_Yolo/yolov4_1_3_608_608_fp16.engine
0:00:03.997042392   698     0x26425b60 INFO                 nvinfer gstnvinfer_impl.cpp:313:notifyLoadModelStatus:<primary_gie> [UID 1]: Load new model:/xavier_ssd/deepstream/deepstream-5.0/sources/objectDetector_Yolo/config_infer_primary_yoloV4.txt sucessfully

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	q: Quit

	p: Pause
	r: Resume

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** INFO: <bus_callback:181>: Pipeline ready

Opening in BLOCKING MODE 
NvMMLiteOpen : Block : BlockType = 261 
NVMEDIA: Reading vendor.tegra.display-size : status: 6 
NvMMLiteBlockCreate : Block : BlockType = 261 
** INFO: <bus_callback:167>: Pipeline running

NvMMLiteOpen : Block : BlockType = 4 
===== NVMEDIA: NVENC =====
NvMMLiteBlockCreate : Block : BlockType = 4 
H264: Profile = 66, Level = 0 
avg bitrate=0 for CBR, force to CQP mode

**PERF:  FPS 0 (Avg)	
**PERF:  28.07 (26.81)	
**PERF:  28.44 (28.37)	
**PERF:  28.54 (28.38)	
**PERF:  28.36 (28.39)	
**PERF:  28.41 (28.39)	
**PERF:  28.52 (28.43)	
**PERF:  28.35 (28.42)	
**PERF:  28.40 (28.42)	
**PERF:  28.45 (28.41)	
**PERF:  28.39 (28.41)

Any suggestions what I’m doing wrong?