Cobalt Radio lets you upload tracks to a webserver which then replaces the static /live.mp3 with a click of a button. You can then setup your in-game boombox to play music from the given link.

THIS IS NO STREAMING SERVER BY ANY MEANS

This software/user-interface is no streaming server by any means.It works by replacing an audio file with another one. There is no continuous audio stream, this means once you have started playing the next track players will have to stop and start their boombox, everytime the track is switched. Think of it more as a cd or cassette player, you turn it off, switch the media and then turn it on again.