Galaxy J : Screen flicker and black lines appear when recording under light source.
This is a normal phenomenon related to flicker of light source that occurs when the light source taking the form of a flashing frequency of the fluorescent lamp to the camera. Flicker phenomenon can mainly be generated at a shutter speed of 1/120 or more and it occurs in the characteristics of the CMOS sensor. It is not a product defect.
This is normal operation which can happen on all camera with CMOS sensor and it’s caused by CMOS sensor’s original specification.