Actually the reason I use two different sets of command strings for AVRCP and IAC is because, the command strings that AVRCP are already defined in gecko, they are the original commands from system message. And what I want to achieve is to let the MediaRemoteControls like a converter that can process all kinds of remote commands and transform them into the correct media commands. So IAC should able to use another set of commands freely, and in the future there might be the wired controls, which are another set of commands.