The Rails Tutorial screencasts (http://zfer.us/EKm97 http://zfer.us/EKm97) always combine audio and video from the same take (using ScreenFlow, natch). I can't

The Rails Tutorial screencasts (http://zfer.us/EKm97 http://zfer.us/EKm97) always combine audio and video from the same take (using ScreenFlow, natch). I can't imagine achieving a good teaching cadence any other way. I also love the verisimilitude of hearing mouse clicks and keyboard clacks synchronized with the action on the screen.