no audio playback on recorded video
I was recently at a concert and was taking a fair amount of videos. When I got home, I started checking them to see how the sound quality was, but I found out that only half of them had audio playback. The last 3 that I took has great video, but absolutely no audio. It's really upsetting because who knows if Slayer will ever tour again. I have an iPhone 4. Any feedback/troubleshooting/tips any of you have will be greatly appreciated.
I wouldn't want the same problem happen tomorrow during the Van Halen show.
Thanks
iPhone 4, iOS 7.1.2