use a Multiple input for deepstream_test_1?

I have found there is an nvstreammux plugin for mux multiple rtsp streams ,
but is there any demo to get more information about nvstreammux’s using,
maybe the reference application with deepstream 2.0 could be a good example, but the picture of reference application’s pipeline is very vague.

Any Idae appreciated!

deepstream-test3 and deepstream-app in Deepstream 3.0