When playing media sound in an app, press the volume key and then click the three dots below the volume panel to set the media volume of the current application independently.
Supported models:
Models with realme UI 5.0 all support
Note: realme 11x 5G does not support
Setting method:
Settings > Sound & vibration > App-specific app volume.

Note: The specific app volume cannot be set separately for the main app and the clone app. The main app and the clone app share the same volume.
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