3 years after Apple TV gained support for 'match content', tvOS 14.5 will implement the holy grail of frame rate matching; support for fractional AND integer frame rates, i.e. both 24.000fps and 23.976fps, for improved video playback without dropped frames.
24.000fps and 23.976fps
Let us rewind for a second. We say that movies are shot and presented in 24 frames per second but most of the time in the living room it is actually 23.976fps (fractional), which is 0.1% slower. The reasons date back to the analog NTSC broadcasting standard and backwards compatibility during the transition from black/white to color. It then stuck around and became an HD standard – baggage from the past.
The 23.976fps format has created various issues with timecodes (because they are in real time), subtitles, syncing etc. We are now well into the digital age and some participants want to throw out the baggage. Netflix, for example, has started to release movies like The Irishman and TV series like The Witcher in exact 24.000fps.
Playing back 23.976 at 23.976 is fine, no problem. However, playing back 24.000 at 23.976 results in a dropped frame every 41 second – some refer to it as "micro-stutter". Most people do no see it but it is one of those things where if you notice it, it gets hard to ignore. And playing back 23.976 at 24.000 results in a duplicate frame every 41 seconds.
tvOS 14.5 will bring improved frame rate matching to Apple TV 4K
Improved frame rate matching
Most streaming players will convert a movie to 50 or 60p for output. It is not elegant, and there are several issues associated with it, but it is the norm.
Apple TV is one of the few streaming boxes with automatic 'frame rate matching' meaning that it looks at the frame rate of the video – 24, 25, 30, 50 or 60fps – and adjusts its HDMI output accordingly. For this purpose it has, since the feature was added in 2017, used fractional rates/output, i.e. 23.976.
Starting from tvOS 14.5, Apple TV will support both integer and fractional frame rates/output, meaning both 24.000 and 23.976, for correct video playback without dropped or duplicate frames. tvOS 14.5 beta 1 supported only integer frame rates (unlike all previous tvOS versions) but the new tvOS 14.5 beta 2 is the first to support both integer and fractional frame rates.
It works in Netflix (correctly playing back both 24.000 and 23.976 content), based on FlatpanelsHD's testing as well as user reports on forums (AVSforum, reddit).
However, it would appear that some apps need to be updated for tvOS 14.5. An app like Infuse now forces 24.000 (on tvOS 14.5 beta 2) but company says that it is aware of the issue and that it will "be getting things tuned up for tvOS 14.5 and the new output options soon".
Also read: tvOS 14.5 features Apple TV support for PS5, Xbox Series X/S controllers
Why now, after 3 years? Well, our guess would be that it actually has a lot to do with where Apple TV is heading. Fractional frame rates and outputs like 23.976 and 59.94 are video things that do not make sense in a modern, digital world. If Apple wants Apple TV to double as a living room game console, if it wants seamless wireless audio (to HomePod or other speakers) in perfect sync, if it wants to enable other non-video tasks in the future, fractional frame rates are simply not ideal. It would also appear that tvOS 14.5 is some kind of preparation for new Apple TV hardware.
Apple has yet to set a release date for tvOS 14.5 but we expect it to be released sometime in March or April 2021.
- Source: AVSforum, reddit, Infuse, Adobe (timecodes)