There is little chance that it comes from my TV because I tested on 2 very different models, and even finding. For the box, it is a Beelink GT1 so with a S912 like you. I’ll wake up tomorrow by restarting the box after the 50hz video settings changes. But anyway, the native frequency of modern TVs in France is 60hz, so the 50hz is not recommended. There must be a way to solve the problem cited in this topic by another means?