Topic summary
Storage aspect ratio
Extracted from the Wikipedia article Aspect ratio (image).
Distinctions
This article primarily addresses the aspect ratio of images as displayed, which is more formally referred to as the display aspect ratio (DAR). In digital images, there is a distinction with the storage aspect ratio (SAR), which is the ratio of numbers of pixels. If an image is displayed with square pixels, then these ratios agree. If, instead, non-square ("rectangular") pixels are used, then these ratios differ. The aspect ratio of the pixels themselves is known as the pixel aspect ratio (PAR) – for square pixels this is 1:1 – and these are related by the identity: