Microphone does not working well when recording video
For past few months, my phone had this kind of problem whenever I wanted to record a video. The audio in the recorded video cannot be heard clearly, even with the loudest volume. It has some bothering sound like sound of wind even though I am far from any wind source like fan or else during the recording. At first I thought it was some problems related to earphone; probably I had unplugged it the wrong way. But after trying a few times, the result is still the same. When I tried to record audio using Voice Memos, the audio is successfully can be heard. This problem only occur when recording a video. Please help me.
iPhone 5s, iOS 9.1