Go to OSX Daily to read How to Watch 4k YouTube Videos on iPhone & iPad
Do you want to watch YouTube videos in 4K resolution on your iPhone and iPad? If you have one of the supported iPhone models, you can watch full 4K high resolution videos on YouTube.
Previously, the resolution for the videos played in the YouTube app capped at 1080p HD even if it was uploaded in 4K. Sure, the current iPhone and iPad flagships don’t have displays that are 4K resolution, but they’re still higher than Full HD and support HDR. With iOS 14 and later, Apple has unlocked 4K playback for YouTube by adding support for Google’s VP9 codec.
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