Beta code for new versions of Apple's various operating systems often yields hints about products that haven't been revealed yet, and the new Apple TV tvOS 14.5 beta continues that tradition. There are references to 120Hz support in the new code, which would make sense in a world where so many of the best TVs are getting 120Hz support, but isn't supported by the current Apple TV.
The code in question was spotted by 9to5Mac – the are several instances of “120Hz” and “supports120Hz” appearing in part that focus on the interface itself.
4K 120Hz support requires HDMI 2.1, which the current Apple TV doesn't include. HDMI 2.1 is a big deal for the best gaming TVs, partly because of its 4K 120Hz support, but also for Variable Refresh Rate. Though Apple has pushed gaming as a big part of Apple TV – and we wouldn't be surprised at all to see some games support 120Hz on a new, more powerful version – we suspect gaming isn't the reason Apple might be looking at including HDMI 2.1.
HDMI 2.1 offers much more bandwidth than HDMI 2.0, which means it can also support greater colour depth. The Apple TV 4K has been a strong choice for AV enthusiasts thanks to Apple's focus on making sure it supports the highest-quality video possible, and HDMI 2.1 support would just future-proof that.
But 120Hz is also interesting because high-framerate movies are just starting to be explored. Ang Lee's Gemini Man was filmed for (deep breath) 3D 4K 120fps Dolby Vision HDR screens, yet barely any cinemas could show it, and the home technology to show it didn't exist yet. Many could show it by dropping some parts of the full presentation (so you'd lose the 3D and HDR, say), but few people have ever truly seen what this movie was filmed to look like.
This new Apple TV and an HDMI 2.1 TV wouldn't totally solve that (3D support at home is long dead), but if Apple creates the first streaming box capable of showing 4K 120fps HDR movies, it jumps back to being the enthusiast's choice. Granted, the list of films created in anything above 60Hz (which the current model can already show) can be counted on the fingers of one hand… without including thumb… but we're still excited by the possibility.
Plus, don't forget that Apple is making its own movies and TV now, and has infinitely deep pockets, so if it wanted to push the art of 120fps movies forward, it could.
Of course, it's also possible that it's just planning to make the interface 120Hz so it looks as premium and buttery smooth on compatible TVs as possible, and anything else is an afterthought we might see in the future. Perhaps we'll find out at its June 7th WWDC keynote.