Hi,
Please try
$ gst-launch-1.0 uridecodebin uri=file:///home/nvidia/sample_720p.mp4 ! nvvideoconvert ! 'video/x-raw(memory:NVMM),format=NV12,width=640,height=360' ! m.sink_0 nvstreammux name=m batch-size=1 width=640 height=480 ! nvvideoconvert ! nvdsosd ! nvvideoconvert ! video/x-raw,format=I420 ! nvjpegenc ! multifilesink location=cap%05d.jpg