video recording but no sound in background only a buzzering noise

hello everyone, i have situation with my iphone 5s and more have been asking me what the problem was.. if i record a video all i get of sound is lots of buzzering noise and far far in the background you can hear the actual sound that was recorded a lil bit if you dont listen closely ur not even able to hear it.. can anyone help me out plz .. i will try replacing thr mic but i dont believe that will solve the problem, because many of my friends do have the same problem i kinda doubt it that so many mic's would stop working at the same time..here is what i think could be the problem because in all the other things making a call recording a whatsapp voice message it all works fine just not while recording a video... so i do thing IOS10 does have bugs in a 5s because thats when it started after that update that probem came up... does anyone know if that could be it or am i the only one knowing that any help??? i would like to hear from others Thank you for taking time to read this wating for some anwers have a nice day....