According to Netflix’s support document, enjoying Netflix content in crisp 4K resolution on your Apple computer requires the macOS 11.0 Big Sur update and the latest version of the Safari browser running on a select 2018 or later Mac computer with an Apple T2 security chip.
This makes zero sense to me. The only Macs that could really benefit from 4K streaming, without an external monitor are the 4K and 5K iMacs yet only two models (the iMac Pro and the new 2020 27-inch iMac) will be able to stream it. Windows machines don’t have any kind of T2 alternative and are still able to stream Netflix in 4K via the Microsoft Edge browser or via the native Netflix app, their only requirement is a seventh-generation Intel processor or a dedicated graphics card.
It makes a lot of sense to me.
Apple’s move to its own Mac chips was planned years in advance, maybe a decade ago. When engineers were building some of the Macs released in the past two years, they knew they’d eventually move to Apple’s own silicon. And that, in turn, has likely guided the decision to not spend their energies optimizing for the video decoders built into Intel chips.
The T2 security chip is basically a system-on-a-chip from the iPhone minus the CPU, GPU and some other parts. Not only does it power Hey Siri, but also encrypts internal flash storage on the fly while offloading a bunch of critical tasks from the main Intel chip.
And one of those tasks is fast video encoding and decoding via hardware-accelerated codecs that basically perform the same job as their counterparts in Intel chips, only faster.
To illustrate my point, exporting a shot-on-iPhone videos in 4K resolution and encoded with the H.265 codec from Final Cut Pro using a Mac with this security chip is a whopping 40 times faster than on Mac computers without the T2 security chip inside.
That’s why, in my view, Apple probably didn’t care optimizing their recent Mac systems for Intel-assisted 4K video decoding. All Macs will soon run Apple chips anyway that include video accelerators for speeding up 4K video encoding and decoding. And that’s why Netflix is recommending using a Mac with the T2 chip to stream their content in 4K resolution smoothly.