I’m looking for a song player that supports the rns format. Does this type of player or codec exist? 
Yup it´s called Renoise, or any mp3player…
No really the thing is that there is no rns player because most rns songs are made with vsts/vsti´s and some with midi…And if they are made with samples they are most of the time very big files, so ogg/mp3s are much better.
Have you ever heard of a cubase player?
K, I get it. 