They are your safe areas. They tell you what content will be seen on a
regular television. The outside rectangle is for the video portion and the inside rectangle is your title safe area. Nifty little idea to help show you where
and what your video and titles will look like on a regular television. It helps
you to keep your "subject" within an area that will be seen when you view it
on a television, warning you that if you go outside of these areas with your
titles or video, you probably won't see all of it. To turn it off, click on the #
sign above the preview window.