Those white lines should not be there and it indicates that something is wrong with the electronics of the camera when shooting video.

Take out the memory chip and play it back video on a computer. If it plays back fine on computer then the playback camera circuits are fubar. If also bad on computer then the anomaly is in the record section of camera.

Repairing those cameras since they are small and the parts are proprietary is an expensive proposition that you would only entertain if the camera was initially a very expensive one. Repairs on less expensive units are simply not cost effective.