RTSP you mean?
I believe the DeepStream app supports rtsp sinks based on GstRtspServer. You just put the proper sink type and port in the config file and expose the port(s) in your dockerfile. My implementation is based on Nvidia’s python implementation and written in Genie (compiles to C).
The Genie sink source is here. The python code it’s based off is here. If you want something you can use directly in C, the Vala compiler can generate a library and header for you from the bins.gs file and some modification… Or you can look into the DeepStream app code.
The Dockerfile I am using is here. Pretty much the only thing you would need to copy is the EXPOSE line if you use DeepStream app just make RTSP port used by DeepStream is the same.
I believe Nvidia also multicasts over port 5000/udp. Never tried that within Docker. The traffic is probably only visible to members of your docker networks unless you use --net host. You will have to experiment on that one. I have little idea how it behaves. If you use the multicast stream you can probably cut out GstRtspServer entirely and just use nginx container(s) to rebroadcast.