情报来源：
https://tinyurl.com/y94g4hrj
YouTube videos available in super-sharp 4K can finally be enjoyed on Apple
devices this fall. Not only will 4K content be available on Apple TV, but
also on iPhone and iPad, according to the first iOS 14 beta.
YouTube 将可以在iPhone, iPad, Apple TV中以4K播放
You might be wondering why it has taken so long for 4K YouTube videos to come
to Apple devices. It’s because the codec Google uses for Ultra HD content —
its own VP9 codec — wasn’t supported by Apple by default.
为什么之前苹果装置播不了4K呢？因为Google高画质影片用了它自己的VP9编码
苹果并没有支援
Google 也没有什么理由为了苹果更改编码
但显然iOS 14开始支援VP9了
iPhone 11 Pro’s display resolution is 2436 x 1125, while the 12.9-inch iPad
Pro’s display resolution is 2732 x 2048. Neither of these come close to the
resolution of 4K video, which is 3840 x 2160.
Now, iPhone and iPad are sharper than Full HD, which is 1920 x 1080, so you
will see some increase in quality when you watch videos in 4K, or even 2K.
They just won’t look as spectacular as they do on actual 4K displays.
不幸的是，无论iPad或是iPhone Max的萤幕分辨率都没有到4K
所以4K和2K看起来都差不多
但应该会比1080p好很多
另外iOS 14多了一个新功能：背部敲击手势
你可以自定手机背面敲两下或是敲三下时会有什么动作
最实用的功能应该是萤幕截图吧
也可以叫出google assistant
自拍的时候感觉也可以使用