Hi,
You can base on this sample:
Gstreamer decode live video stream with the delay difference between gst-launch-1.0 command and appsink callback - #6 by DaneLLL
And run the pipeline like this:
rtspsrc ! rtph24depay ! h264parse ! nvv4l2decoder ! nvvidconv ! video/x-raw,format=RGBA ! videoconvert ! video/x-raw,format=BGR ! appsink