Camera App sound problem

Hi, i have a problem with native Camera app. I'm using 6s with iOS 12.2.

It records sound in video only if there's a noise, otherwise if there's silence it records just static frequency noise.

Sound in video normally works in other apps like Messenger, Instagram and some random camera app that i've installed just to check if it's not a broken mic.

I've tried resetting whole iphone and set it as new and it didn't worked. I appreciate any help.