Noisy video (camera)

I have a problem with my Samsung Galaxy S5 (G900A) where my video recordings are noisy.

Even in the quietest of conditions I hear this hissing sound in the background in my videos that I record using my phone camera.

I've searched the web and found out that I'm not the only one, but I can't seem to find any solution to it.

I've cleared the cache partition, the phone isn't wet...

Any suggestions? Such an expensive phone with such a big problem...