Bad audio quality when recording from Camera

Hello

I have a strange problem with my iphone 5. When i register video from camera app the audio quality is not very good. I thought that this would be a microphone problem.However if i register from voice memos the audio is very good. Also the others can listen me very well when speaking on telephone so i don't know anymore that this is a microphone problem or not? The video quality is excellent only audio in video recording is like mono and not very loud as it was on my 4s. Is this a software or hardware problem?

Thank you.