VLC picture is too late to be displayed

did you boost Jetson device clock?

$ sudo nvpmodel -m --for MAX perf and power mode is 0
$ sudo jetson_clocks

do you run with deepstream-app , or deepstream application?
if deepstream-app, you can use “export NVDS_ENABLE_COMPONENT_LATENCY_MEASUREMENT=1” to check the plugin latency.
if deepstream application, refer to Slow real-time performance when running custom YOLOv3 app - #7 by mchi to measure the output fps