I am running Marshmallow AndroidTV on Mi Box.
The YouTube app lately started playing videos at 4K (I can see 4K icon next to title, and also when I enable "nerd stats").
Needless to say, Mi Box stutters on 4K content. But I don't need it! My TV is 1080p.
How can I disable 4K on YouTube app? I found nothing in YouTube app settings.
Either downgrade or use an alt front end, like SkyTube or NewPipe
Hello, the issue is with some 4K videos, I actually had to report the issue with Youtube because some 4K videos play fine but others stutters a lot, my suggestion is to test different 4K videos to see which one work and which one does not, also try to delete the data of Youtube in the settings to see if that helps.
There is no way to disable 4K playback because youtube adjust the picture quality automatically depending on the TV where the device is connected, so if you play a 4K video on a 1080p TV then the video will play up to 1080p.
Finally you should report the issue with Youtube, that way, the more reports they get, the sooner the issue gets fixed, you can make the report here: http://youtube.com/androidtv_feedback
You sure it's not 1440p? That resolution starts with 2556 pixels in the horizontal number. 1440p is what the youtube app plays for me when I'm at 1080p but a higher resolution like 4K or 1440p is available.
Also, weirdly I haven't run into a 4k 30fps video in any codec including inside of youtube that my Mi Box with the latest non beta firmware can't play without dropping frames.
All you can do at this time is downgrade your Youtube app to 1.3.11 and select 1080p only. Then turn auto app updates off. The new version has no resolution selection right now, but may bring it back in the future.