Hi,
For using appsrc and appsink, you would need to run the pipeline in C code. Please refer to this sample:
Latency issue: nvv4l2h265enc accumulates four images before releasing the first - #3 by DaneLLL
In running gst-lauch-1.0 commands, you may try UDP. Please check Jetson Nano FAQ
Q: Is there an example for running UDP streaming?