This has always bothered me on iPhones. It's true that it makes sense, but it doesn't stop bothering you. I mean that you can't record a video using the Cmera native app while your iPhone is playing some music.
Because the phone's microphone necessarily has to pick up the sound for the video to be good, iOS chooses to pause the music to get it done perfectly. This, of course, only happens to record videos; If you wanted to take a picture, the music keeps playing good.
But something has changed on the iPhones 11, 11 Pro and 11 Pro Max, whether by Apple's carelessness or intentionally. And yes, only in the new devices, since only they have the feature QuickTake, which we comment on the video below:
With this feature, you hold the button that shoots the photo for a few seconds (or drag it to the right to lock the video and not keep pressing the button) with “Photo” mode selected to start a video recording.
And on it, if any music is playing on the iPhone, the system does not pause the track so that the audio is captured more satisfactorily on the video ie you leave your video with a "soundtrack"!
As I said, the possibility of this behavior being a big bug, so it wouldn't surprise me if, in some future iOS update, Apple would change that. Still, anyone who bothered with this limitation and has an iPhone 11/11 Pro (Max) in hand can take advantage of the / bug feature. 😉