Safari users are facing a rather strange issue while trying to play 4K YouTube videos. According to many users of Apple’s browser, the are unable to play YouTube videos in native 4K resolution. The issue was first highlighted by a reddit user who found out that there was no option to play YouTube videos in 2160p resolution.
The issue seem to be related to Safari browser only and that too for recently uploaded 4K videos. The same 4K videos are accessible using Chrome or Firefox. One explanation for this reasons could be the shift in YouTube video codec. Google has shifted to VP9 codec for delivering 4K YouTube videos and it looks like Safari doesn’t support the new codec.
Reddit users also found that 4K YouTube videos that were uploaded before December 6, 2016 can still be played in full 4K resolution on Safari. According to an Apple representative, Safari doesn’t support VP9.
What’s more weird about this issue is that, the video can be streamed in 4K without any issues if it is embedded on a website other than YouTube, just like the Apple Campus 2 drone flyover video. This means that the VP9 codec requirement only applies to videos viewed directly on YouTube.