Video
Aspect Ratio
01 — Definition
The width-to-height ratio of an image. In practice: 16:9 (1.78:1) for HD and UHD, 4:3 for the SD of old, 2.39:1 for anamorphic cinema, 1:1 (square) and 9:16 (vertical) for social media. Non-standard ribbon displays — 8000×600, say — call for a custom media server canvas, and a mismatched ratio means black bars or stretching.
02 — In the field
Confirm with the creative team whether 16:9 content on a non-standard screen will be letterboxed or cropped. Never stretch: it always looks wrong, and the client will spot it.