It actually requires login, i have just redacted it, the actual command i send begins with http://user@pass, i just removed the user/pass part of the command, as I didn’t want to post it online, so i think it should be correct. (especially since it works in a sense as a REST-switch)
It is a regular media player, that plays a file when it receives the command.
https://wiki.jriver.com/index.php/Web_Service_Interface