The Youtube app on Android lets you play videos at up to 4K resolution. All you need is a phone with a 4K display and a decent internet connection, and you're good to go. However, it seems like Google has now opened up unsupported video resolution options on some devices, allowing some users to play 4K videos on a device with a low-resolution display.

According to a couple of recent posts on the YouTube subreddit, the YouTube app on Android now lets you play 4K videos even if you don't have a supported device. As the following screenshot from Reddit user u/Liskowskyy showcases, the app now shows all video resolution options up to 2160p60 regardless of the screen resolution.

YouTube app Android unsupported video resolution options

While some think that this change is unintentional, a user in the comments on another thread by Reddit user u/sssxun speculates that the change may not, in fact, be a bug. They claim that by allowing unsupported video resolution options on devices with lower resolution screens, videos will have higher fidelity than while playing them at a supported resolution. I tested this on a device with a 1080p display, and videos do seem to look a lot better when played at 2160p60.

As another commenter points out, the stark video quality improvement is due to the fact that the higher resolution videos have a higher bitrate and, therefore, less blocky compression artifacts in high motion screens. Playing higher resolution video on a low-resolution display also increases the sharpness because of downscaling, making the video appear better overall.

The unsupported video resolution options seem to be widely available on various versions of the YouTube app on Android. I checked a couple of devices, and I was able to find the additional resolution options in all of them, despite them running different versions of the app. This leads me to believe that it may have been enabled via a server-side switch. We'll update this post once we receive any additional details about this change from YouTube.