According to Netflix support document, macOS 11.0 requires Big Sur update and latest version of Safari browser running on a selected Mac computer from 2018 or later with an Apple T2 security chip, to enjoy Netflix content in sharp 4K resolution on Apple your computer.
From a Reddit post, via The Loop:
This makes zero sense to me. The only Macs that can really benefit from 4K streaming, without an external monitor, are the 4K and 5K iMacs, but only two models (iMac Pro and the new 2020 27-inch iMac) will be able to stream it. Windows computers do not have any kind of T2 option and can still stream Netflix in 4K via the Microsoft Edge browser or via the original Netflix app, their only requirement being a seventh generation Intel processor or a dedicated graphics card.
It makes a lot of sense to me.
Apple’s transition to its own Mac chips was planned many years in advance, perhaps a decade ago. When engineers built some of the Macs released in the last two years, they knew they would eventually move to Apple’s own silicon. And that, in turn, has probably driven the decision not to spend energy on optimizing for video decoders embedded in Intel chips.
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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 drive Hey Siri, but it also encrypts internal flash storage while unloading a series of critical tasks from the Intel chip.
And one of those tasks is fast video encoding and decoding via hardware-accelerated codecs that basically do the same job as their Intel chip counterparts, only faster.
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To illustrate my point, it’s 40 times faster to export video recordings on iPhone in 4K resolution and encoded with the H.265 codec from Final Cut Pro with a Mac with this security chip. inside.
Therefore, in my opinion, Apple probably does not care about optimizing the latest Mac systems for Intel-assisted 4K video decoding. All Macs will soon be running Apple chips anyway, which include video accelerators to speed up 4K video encoding and decoding. And that’s why Netflix recommends using a Mac with the T2 chip to stream content in 4K resolution evenly.