4K video usually found on high end cinematography devices. However, OmniVision release 2 sensor that is able to recording a video up to 4K resolution for compact camera or smartphone.
Companies engaged in the manufacture of digital imaging sensor that has a 1/2-3 inch format, is OV16820 and OV16825 is a sensor in question.
16 MP sensor is capable to record a 4K video (3840×2160) on 60 fps. Resolution could be improved (4608×3456) on 30 fps rate.
That 2 sensor is expected to be produced in large quantities in the Q4 this year.