How to see 4K video in the YouTube Sony Xperia xz Premium?

[Justluk]

Hi, I was trying to watch videos in YouTube with 4k resolution but apparently the phone doesn't switch the display resolution and stucks in full HD (1080x1940) also if I change the stream quality to 4k as you can see at the voice viewport when you open statistics for nerds. There is a way that I don't know to be able to switch the display to 4K resolution in YouTube?

Thanks

[Lord_viridis · Accepted solution]

That's probably because the UI on the Smart TV is 4k, on Xperia, only the video feed is 4k, the UI remains locked at 1080p at a system level.

This is why when you set video to 144p, the viewport will stay locked at 1080p, because even with 144p, the UI is nice and smooth.

This is why you see the *2 or *3 on some TVs, the standard YouTube UI is either 720p or 1080p, the multiplier is the UI scaling so 1920x1080*2 means the 1080p UI is scaled x2 to fit into 4k display, likewise some see 720x3 when the UI is larger font etc.

The video feed is separate to viewport, and is described in the stats for nerds video details.

[Lord_viridis]

I mean, I think this shows it even using your pictures..

[Justluk]

Thank you for the explanation, I didn't thought that the viewport show the UI resolution and not the display's one. Yes the smart TV has a 4k UI that's why... My bad, thanks again!