Looking for an app to recorder video while music is playing

Screen recorder.

https://troones-recorder.en.uptodown.com/android

It is ad-free, and can use the forward facing camera to record you.

Android makes it very difficult to record from an internal source, and so it is typical for the sound to be recorded with the same microphone that you use when making videos or are on a call.

I haven't tried what you are attempting, but I think that it should work.

As long as your music player works in the background (most do) and you set up Screen Recorder correctly I think it will work.

 

Are you still talking about the screen recorder app, or an actual camera app?

The screen recorder that I mentioned does not do such a thing, as far as I know.

If it does, then thereare settings as far as how to control the app, and I use the notification bar settings.
All the controls are available on the notification bar, and only appear when I pull them down.

After the recording is complete, I use the 'Trim' feature to edit that out of the recording.

If it is an actual caamera app that you want, I use Simple Camera from Simple Mobile Tools.

Simple Camera - Contains no unnecessary functions (A camera with flash, zoom and no ads.) - https://f-droid.org/app/com.simplemobiletools.camera

 

I believe within the settings of that camera app, there is an adjustment to turn the control icons off.

If this doesn't work, I use an excellent video editor called YouCut, from InShot.

It is simple to use, and has many options to customise your videos.

https://apkpure.com/p/com.camerasideas.trimmer

There is another editor by the same company if YouCut isn't your thing.

https://apkpure.com/p/com.camerasideas.instashot