Why does Xiaomi's mobile phone 2s plug in headphones have external sound? Only music and video are headphone sounds.

This is a humanized function of MIUI system. Imagine if you are listening to music and something happens suddenly, take off your headphones and put them aside. At this time, if a call comes in and there is no ringing outside, then you will definitely miss the call. MIUI system adds this function according to some user feedback. When listening to music on the phone, there is absolutely no sound playing outside.