The sample above is embedded with a javascript file, the app takes any parameters it finds in the URL first, then in XML... if they aren't specified anywhere, the default value is used. Songs and their info can only be added in the XML file.
I added this form below so you can play with the URL variables. You'll probably just set the parameters in the XML file most of the time, but sometimes it's nice to be able to change them on the fly through the URL as well.