Hi,
On r32.3.1/TX2, we try the two pipelines and don’t observe the issue.
$ ./test-launch 'videotestsrc ! nvvidconv ! nvv4l2h265enc ! h265parse ! queue ! rtph265pay name=pay0 pt=96'
$ ./test-launch 'videotestsrc ! nvvidconv ! nvv4l2h264enc ! h264parse ! queue ! rtph264pay name=pay0 pt=96'
On a PC with Linux Ubuntu 18.04.2 LTS, we can run
vlc -vvv rtsp://10.19.107.68:8554/test
And on PC with Windows, we can open the stream in VLC player.
Not sure if it helps but you can try to clean the cache:
$ rm .cache/gstreamer-1.0/registry.aarch64.bin
And if you have installed plugins-ugly, you can remove it and try. It triggers a issue in decoding a RTSP stream: