Letterboxing

The term comes from film, where widescreen movies were shown on square televisions with black bars at the top and bottom. In short form the same idea runs the other way: a horizontal recording sits in the middle of a tall phone screen, and the empty space is filled with black, a blurred copy of the video, a title or captions.

It matters because cropping and letterboxing trade different things. A vertical crop fills the screen and makes a face large, but it throws away most of the width. Letterboxing keeps everything, which is the right call when the important information spans the frame, such as two people side by side, a game HUD, a slide or a wide establishing shot.

The cost is size. The video occupies roughly a third of the screen height, so faces and text are small on a phone, and viewers scrolling fast may skip a clip that looks unfinished. The empty space works best when it is used for something, usually a hook title above and captions below, rather than left as plain bars.

In practice clippers use letterboxing selectively: crop or reframe when one speaker carries the clip, and letterbox when the frame cannot be cropped without losing the point. Crayo's Letterbox layout in AutoClip keeps the whole frame with no crop, and the other layouts follow or crop the subject instead.