Fantasy Grounds does not currently provide any built-in video or audio streaming. You can use any of the popular platforms alongside Fantasy Grounds to do this in your games. Just make sure that everyone in the group is using the same option. Popular choices are Skype, Google hangouts, Teamspeak and Discord. Fantasy Grounds now has an official Discord channel up that you can join below. It's' free and supports streaming of audio. It's also a great place to use as a lobby to look for a group to join, chat with other FG members and chat.