No 4K option in Safari/Youtube

It looks like YouTube uses the VP9 video compression codec rather than the H.264 that Safari supports, so Safari will only play videos up to 1440p. If you use Chrome, you can watch 2160p.

Source: https://9to5mac.com/2017/01/12/youtube%E2%80%A4com-no-longer-supports-4k-video-p layback-in-safari/

Edit: I just saw all the other replies to this so I've contributed nothing new.

Safari doesn't support VP9 (Google's latest codec competing with HEVC/H.265). Safari must be using the H.264 version of the videos that are only encoded up to 1440p (2.5K) with H.264. (Internet Explorer is the only other major browser that doesn't support VP9, it has been discontinued anyway.)

I took screen shots of the same frame (of same video, obviously) with Safari and Chrome on my Retina MacBook Pro 15-inch (2880x1800 screen resolution, and 3360x2100 screenshot resolution). Safari was limited to 2.5K 1440p, Chrome shows 4K 2160p, yet the color itself is different. The VP9 in Chrome looks washed out or just plain brighter without as much dark detail. Safari looks much better even without the higher resolution, this supports the argument that HDR is more important than higher resolution.

Is this a true difference in the Codec, VP9 vs H.264? Or is it just the different way Chrome and Safari show colors?

I also compared Chrome's 1440p version and it still looks washed out compared to Safari. (But it is likely the same VP9 encoded version of the video, so that doesn't mean anything to look at the same resolution.) I would be shocked if the different codecs really have differing color with everything else being equal.

Safari: (resampled to 1440x900)

Chrome: (resampled to 1440x900)

It helps to download the images and switch between them in place to see the color difference.

Here is 2160p (4K) YouTube video for Porsche Panamera. Can you view it in 4K?

I'm also able to watch that Panamera video. Like the OP, I also can't view any current Youtube 4k videos, it only shows me up to 1440p. Everything works fine on Chrome though, which makes me think this is a sole Safari issue. I've updated Flash too, to no avail. 😟

Im having a similar issue as well and for the time being I'm forced to use Google Chrome for the moment!

Praying for this issue to be resolved

If you can watch that 4K video that I posted earlier as 4K HTML5 streaming content in Safari, then the problem is not Safari.

There may be 4K video posted to Youtube that is not in a compatible video format that can be converted, and streamed correctly in HTML5. It may play in other browsers where the video format is natively supported, and HTML5 streaming content is not used.

We can both laugh about my lack of technical understanding of the translation process for that Youtube server content into HTML5 streaming video. Only Apple knows what is inside Safari — it might be two rats running in opposite directions on a treadmill for all I know. For the curious, here are the Youtube video encoding guidelines.

Hi.

The funny thing is that when you use Final Cut Pro X's direct YouTube 4K export, it still doesn't show up in 4K in Safari (but does on Chrome...) 😐

There's an article about this issue: https://9to5mac.com/2017/01/12/youtube%E2%80%A4com-no-longer-supports-4k-video-p layback-in-safari/

YouTube is now using the "VP9" codec for 4k videos. Safari has not been updated to use the new codec, and so cannot play the videos. You can see more about VP9 here and about YouTube using VP9 here.