No sound in video on Iphone4

Hello i have this problem with my Iphone4 ios ver5.0.1(94A405) model MC605GB when i shoot a video i dont have a sound when i play it on mi phone and computer. Can that be a software problem? Are there any setting for the camera where its muted? The mic hole is not covered btw

 

No there is sound on the movies that i have on my phone or when i play a video from youtube, even i have sound when i am doing voice memos, i dont have sound when i shoot a video from my iphone and after that i play it.

 

Cmon noone have an idea almost 800 viewes and no replay