Is that the stock camera app or a different one that you downloaded? Do you have any mode, such as sound and shot, enabled? You could try clearing storage for the camera app and see if that symbol stays there.
It's the stock camera app. I do have that the voice activation turned on and that's the first setting I tried turning off because the icon kinda looks like a soundwave, but like I said, none of the changes I made to the settings did anything.
I do have all my photos backed up to Google so I went into the Google Photos app and "freed up" 3.06GB and then also went into the Camera app info and cleared the cache. Not sure which one of those steps did it, but the icon is gone from camera screen.
Weird.... I'd still like to know what the icon was for though???
It is definitely the voice activation icon. However, mine was static and would not go away. I just tried the voice command again and the icon came on the screen but was not animated like in the video. And after taking the picture it stayed on the screen again. I used another voice command and after taking the picture it disappeared from the screen and no longer appears on subsequent voice commands.
So then I cleared the camera app cache and data, but that didn't fix the voice command icon behavior. My camera version is 12.0.01.48.