I personally use this command in terminal

   avconv -f   pulse -i default -f x11grab -r 15 -s $(xdpyinfo  | grep dimensions | awk -F ' ' ' { print $2 } ' ) -i :0.0+0,0 -acodec libmp3lame -vcodec libx264  $(date +"%m%d%Y_%H%M%S_$HOSTNAME")_screencast.mp4

If you want a sophisticated one try this http://www.maartenbaert.be/simplescreenrecorder/

It's open source and looks nice.

EDIT:

For inline audio try this

pavucontrol

then switch to output devices then click on green check mark with tooltip Set as fallback