The slide master provides a consistent way to format slides in a PowerPoint presentation. It also makes moving slides between presentations easier, as you do not need to reformat the slide when it is moved.

If you need to extract a section of video (or audio) you can use iTunes to create a file with just that section. The material being prepared needs to be editable (like video you film) rather than protected (like video you may buy).

A demonstration of drawing using Open Office.