Oppo
Change Media Volume auf Oppo
Media volume on Oppo phones governs playback level for apps and their content, separate from ringtone, notification and call volume. Videos, games, streaming apps and music players all pull from this single slider, so a low setting here mutes content even when the ring volume is turned up.
ColorOS keeps these volume channels independent by design. This lets you silence a video while still hearing incoming calls, but it also means the volume buttons sometimes control the wrong channel if no media is currently playing. On many devices the side buttons default to ringtone volume unless an app is actively producing sound.
To set the level directly, open Tap on Settings ➔ Tap on Sound & vibration ➔ Set the Media volume. Drag the slider to the level you want; changes apply immediately to any app currently playing audio.
If the volume buttons still adjust the wrong channel, start playing media first, then press the buttons. That forces the on-screen overlay to target the media channel instead of ringtone.
If audio is missing entirely rather than just quiet, check the app's own in-app volume control or a muted media output device such as a paired Bluetooth speaker before adjusting this slider again.