Aspect ratio

Aspect ratio describes an image's shape by comparing its width with its height. A 1920 × 1080 image and a 3840 × 2160 image both have a 16:9 ratio. One contains more pixels, but their overall proportions are the same. Apple’s aspect-ratio definition

BetterDisplay uses this relationship when filtering display modes and generating compatible scaling choices. A matching ratio helps preserve the shape of an image. It does not mean that the two images have the same resolution.

Rotation can swap width and height. Cropping or stretching a stream can change its shape independently of the selected display mode.

See Display Mode for the related options.