Will you benefit from the Apple TV’s new 21:9 aspect ratio?

Apple this week released the latest developer beta of tvOS 18.2, the software that powers the company’s Apple TV 4K streaming media devices. As previewed during the WWDC 2024 keynote, the new software includes support for 21:9 and several other aspect ratios that are wider than 16:9, which has become the dominant shape for modern TVs.

Why does that matter?

Most of us have experienced letterboxing or pillarboxing — that’s when a set of horizontal or vertical black bars frame the content on our TVs. It happens when there’s a mismatch between the aspect ratio of a movie or show and the aspect ratio of your screen.

A lot of modern content, especially shows and movies developed for streaming services like Netflix, Max, Paramount+, or Apple TV+, is shot in 16:9, so letterboxing that content on 16:9 TVs isn’t necessary. On the Apple TV 4K, even the user interface is formatted for this ratio, which keeps things looking good.

However, some folks own projector screens or widescreen monitors with non-16:9 aspect ratios. For these people, all Apple TV 4K content ends up with those pesky black bars because the device’s signal is formatted for 16:9. When tvOS 18.2 arrives for everyone in December, the software should automatically detect the ratio of your display, and reformat itself to match.

Sigmund Judge / X via FlatpanelsHD.com

If that detection fails, a new Aspect Ratio settings menu will let you manually select the appropriate one for your setup. Available ratios are 16:9, 21:9, 2.37:1, 2.39:1, 2.40:1, DCI 4K, and 32:9.

It will be the first time that someone who owns a 21:9 projector, or who uses an anamorphic lens to achieve a ratio like 2.39:1, can get the Apple TV 4K to produce a perfectly proportioned and fullscreen image.

So how many people will benefit from the new settings? “It really won’t affect very many,” said Jeff Gosselin, chief experience officer at Cloud 9 AV, a Toronto-based custom home theater installer. “Any new theaters we have done in the past 15 years have all used 16:9 screens. For any ultrawide projection systems, this will be an enhanced viewing experience.”

Pillarboxing will still likely occur when watching 16:9 content on such a screen, but when 21:9 content is available, it should play in fullscreen, with no black bars.

Presumably, app developers — like the services mentioned above — will have to update their apps to ensure that their content displays correctly under the new aspect ratio settings. But eventually, this will become the norm.