From googling 'Fmod Sound System' it appears to be some audio software which allows you to add music into online games. So these connections must be using your stream for their games background music rather than just ripping the audio. But I can't say for certain!
Simply kicking the IP won't do much as they can easily reconnect. If this is a problem for you then you should ban the IPs and/or block the user agent from your stream.