UNRAVEL ASPECT RATIO
CHEAT SHEET v2.2
Calculating out the required resolutions for particular aspect ratios can be a little tricky so we’ve created a cheat sheet to help simplify this process. Below is a cheat sheet for the resolution to use when exporting for various aspect ratios and frame sizes. If you spot any faults or have any suggestions for updated versions, please let us know.
Note: Many people refer to 2.35:1, 2.39:1 and 2.40:1 but these days they are usually all referencing the 2.39:1 aspect ratio. 2.35:1 was used in films prior to 1970 and 2.40:1 is an incorrect rounding from 2.39:1 to 2.40:1. Having said this, there are times when delivering at 2.40:1 is actually required rather than 2.39:1 - Bluray's spec for anamorphic/scope content is one example. As a result – all variants are included in this document. When it comes to anything between 2.35-2.44 we find it's best to look at your target destination and run with their predefined spec. (i.e. Blu-ray @ 1920x800, 2KDCP @ 2048x858, 4KDCP @ 4096x1716 etc.). It always pays to check what your destination is expecting to receive from you rather than trying to convince them you have it the right way round! 2.39 aspect ratios have been calculated based on Digital Cinema Scope 2.39 aspect ratio which is actually 2048/858 = 2.386946386946387. This has been done for pragmatic reasons as we assume that most that are targeting a strict 2.39 ratio are doing this to match a Scope aspect ratio in cinema.
From version 2.2 onward, all ratios that don’t divide perfectly have been rounded down to their closest even integer. This has been done to better support
field encoding, codec requirements and general sanity. Value’s have been rounded down rather than up so that image data is never caught halfway
between framing and blanking. I.e. It’s better to crop imagery slightly than to have pixels only extending partially into a new line.