情報來源：
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 將可以在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.
為什麼之前蘋果裝置播不了4K呢？因為Google高畫質影片用了它自己的VP9編碼
蘋果並沒有支援
Google 也沒有什麼理由為了蘋果更改編碼
但顯然iOS 14開始支援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，無論iPad或是iPhone Max的螢幕解析度都沒有到4K
所以4K和2K看起來都差不多
但應該會比1080p好很多
另外iOS 14多了一個新功能：背部敲擊手勢
你可以自定手機背面敲兩下或是敲三下時會有什麼動作
最實用的功能應該是螢幕截圖吧
也可以叫出google assistant
自拍的時候感覺也可以使用