Volume per App: Sound Mixer

Keep the music loud and the video quiet, at the same time. Android has one volume for everything; Volume per App gives you a control for each app that is playing.
HOW TO USE
• Press a volume button: a panel opens over any app, with one bar for each app that is playing and one for the main volume.
• Drag each app's bar to the level you want. The setting is saved and comes back whenever that app plays again.
• On the main screen, every app playing audio appears side by side, each with its own bar.
FEATURES
• A separate volume for each app: music, videos, live streams, games, video calls.
• Panel on the volume button, a little above the middle of the screen, on the side you prefer.
• Three panel styles: Waves, Pill and Glass.
• Several apps playing together: one app no longer pauses another (when the device allows it).
• Reset everything with one tap: all apps go back to normal volume.
• Available in English, Portuguese, Spanish and French.
HOW IT WORKS
Android does not let a regular app change another app's volume. Volume per App uses Wireless debugging, a built-in Android feature (Android 11 or newer), to get that system access, with no computer and no root. The app includes a step-by-step guide that shows where to tap:
Allow notifications (the pairing code is typed into them).
Turn on developer mode.
Turn on USB debugging (no cable needed).
Pair Wireless debugging with the 6-digit code.
You pair only once. After restarting the phone, just turn Wireless debugging on again. If Developer options were off, the app turns them off again after connecting.
PRIVACY
• No accessibility service.
• It does not read your messages or your screen and does not send your data to the internet.
• No ads.
FREE TRIAL AND PURCHASE
Use everything free for 7 days. Then a one-time payment through Google Play unlocks the app forever, with no subscription. If you already bought it, the purchase comes back by itself when you reinstall or change phones.
GOOD TO KNOW
• Calls and alarms still pause other sounds, as Android requires.
• Some apps keep changing their own volume; for those, the level may fluctuate.
• On Samsung phones, turn off Auto Blocker before turning on debugging (the guide reminds you).