How do I find which app is playing audio files?

[S_e_a]

AIMP was my default audio player. But recently I noticed that when I tap audio file, another app is playing it. It looks like a small popup with white background, without app name or any information, only song name, play/stop button and player timeline.
I have made a reset for all apps settings, expecting next time I will see a dialog asking which app I want to use for playing audio. But that unnamed player appeared again, without any dialog.
Phone Samsung Galaxy J7 2016

 

[B. Diddy]

Welcome to Android Central! Are you using a file manager app to select the music file to play? If so, which file manager? Many file managers have their own basic mp3 player.

 

[S_e_a]

Thanks! I'm using a default manager. Also I use Nova Launcher, if that matters.

 

[B. Diddy]

Try testing out another music player, like PowerAmp. If it asks you if you want to use that player when you select the music file, then maybe there's an issue with AMP. Did you have any recent updates to the system or to AMP? If so, there might have been some kind of incompatibility that was introduced--I saw a couple of reviews on Google Play suggesting that there might be issues with Marshmallow. Send some feedback to the AIMP developers: support@aimp.ru

 

[S_e_a]

I've downloaded PowerAmp, but no success. Again it doesn't ask me which app I want to use.
Also I've downloaded app called "Default App Manager" and added PowerAmp as default for audio.
And also installed Astro File Manager.
No results. No matter do I choose file in default file manager or in Astro, that small player is playing again.

 

[B. Diddy]

When you say you're using the default file manager, do you mean My Files? To be sure you're using the stock Samsung app and not some 3rd party file manager that may have sneakily installed itself, try booting into Safe Mode and selecting an mp3 file to play again. https://support.t-mobile.com/docs/DOC-30290

 

[anon(123856)]

Have you tried playing them through the app? If that works maybe there's a setting to make it the default player.

Also have you looked at settings>Apps>Default Apps?

 

[S_e_a]

I have figured out which app is that! It is Google Play Music. I disabled it and now when I choose audio file, error is displayed: "Unable to find application to perform this action". And yes, I use My Files.

 

[S_e_a]

@badcat Yes player apps are working. And I tried to set default app but it did't affect the phone's behavior

 

[S_e_a]

I've installed Samsung music player. Now almost similar player is popping up when I choose audio file.
Can't understand why earlier it was possible to choose my favourite player and now it is impossible
Screenshot:

 

[anon(123856)]

About the only thing I can come up with is maybe uninstall AIMP and reinstall it. Sorry I can't be of more help.

 

[B. Diddy]

Try wiping the system cache partition: https://support.t-mobile.com/docs/DOC-30305

I would still also contact the developer if you haven't already. They might be aware of the issue.

 

[S_e_a]

I've wiped cache partition but that didn't help.
Tried so many ways, nothing helped. I give up >_<
Thank you so much for trying to help me!
@B. Diddy No I didn't contact developers.

 

[B. Diddy]

What happens if you long-press the mp3 file in the My Files app? What options does it give you?