When playing back video, the only sound is a low static...

I have a black 32GB iPhone 5 (AT&T) running OS6 and last night, I took some video of our baby crawling for the first time. My wife and I were super excited obviously, but when I played the video back, you could see what was going on, but could not hear ANYTHING. The only sound that came out was a low static with occasional hisses and pops. I played back older videos from my Photo library on the phone, and they played fine. BUT, any new video that I've taken since last night only plays back with static. Is anyone else having this problem?

As for other troubleshooting I've done: "yes" the sound was on and volume was up, "yes" I can play music from my phone, out loud and through headphones, and "yes" other apps/games/recorded sound play back just fine. (meaning, I can take voice memos with my phone and they play back just fine).

It's only when I take video that the sound turns to static on playback. VERY FRUSTRATING. Please help!!