Aspect ratio (image)

The aspect ratio of an image is its displayed width divided by its height (usually expressed as "x:y" or "x×y," with the joining colon or multiplication symbol articulated as the preposition "by" or sometimes "to"). Currently, the most popular standard ratios are the anamorphic (2.39:1), the traditional 4:3 (1.33:1), still used for many television screens, and its modern 16:9 (1.78:1) successor, used in high-definition television and European digital television. These are the three standards specified for MPEG-2 (DVD) video compression, the last one being also the Blu-ray/HD DVD standard and a modern compromise between the two popular 35 mm widescreen cinema standards (1.66:1 in Europe and 1.85:1 in USA and UK).