YouTube testing Premium subscription exclusive 4K video playback

Video-sharing platform YouTube has been running a test that places its 4k video-playing capabilities behind its premium subscription.According to The Verge, it has been reported by some users in recent weeks that they have been seeing playback of 2160p resolution video restricted with text labelling it as a premium feature. YouTube has since confirmed via Twitter that those seeing the new restrictions were part of an experiment to better understand the feature preferences of Premium and non-Premium viewers. It isn't clear if YouTube will actually restrict all non-Premium users to 1440p video quality, and the company is directing users to leave feedback on the restrictions in order for the Google subsidy to "make improvements," reported The Verge.A YouTube Premium subscription service grants access to YouTube Music Premium, as well as in-app downloads, background play, and most importantly: ad-free viewing.