Switch between four hdmi sources on a single hdmi display with support for mhl and video resolutions up to 4k the vs421hd4k 4 port hdmi 4k switch lets you share a display or projector with four hdmi enabled audio video source devices the switch features four independent inputs that each support 4k resolution and 71 surround sound audio the 4 port switch also features mhl support on hdmi input port 1 enabling video output video from mhl enabled mobile devices such as samsung galaxy tab