Photography is about composition. It's not enough to just point a camera at a subject, set the camera to automatic and hope for the best, a photographer must understand the elements of composing an image to get the most from a given experience. Framing is the process of actualizing proper composition of memorable photos.
Framing techniques can be considered subjective, what one person finds interesting another person may find meaningless. The rules for framing video or film are basically the same as the rules that apply for still photography.
A few good rules for proper framing are about following horizontal and vertical lines. Making sure horizons are level or building edges are straight vertically in the frame up and down. This is a good way to help Gage framing when shooting an image. The rule of thirds also applies when framing as it does when considering composition of a photo.
When presenting an image everything in the frame helps to tell the story and is important although the subject is usually the primary focus of a photo when considering framing, many factors should be kept in mind.