Merge pull request #6457 from frenzibyte/ios-fix-mixing

Fix iOS audio session allowing other audio to mix

osu.Framework.iOS/GameApplicationDelegate.cs

@@ -35,6 +35,10 @@ public override bool FinishedLaunching(UIApplication application, NSDictionary l
             SDL_SetiOSEventPump(true);
 
             var audioSession = AVAudioSession.SharedInstance();
+
+            // Set the default audio session to one that obeys the mute switch and does not mix with other audio,
+            // and insert an observer to disregard the mute switch when the user presses volume up/down.
+            audioSession.SetCategory(AVAudioSessionCategory.SoloAmbient);
             audioSession.AddObserver(output_volume_observer, output_volume, NSKeyValueObservingOptions.New, 0);
 
             host = new IOSGameHost();

osu.Framework/Audio/AudioManager.cs

@@ -406,8 +406,8 @@ protected virtual bool InitBass(int device)
             // without this, if bass falls back to directsound legacy mode the audio playback offset will be way off.
             Bass.Configure(ManagedBass.Configuration.TruePlayPosition, 0);
 
-            // For iOS devices, set the default audio policy to one that obeys the mute switch.
-            Bass.Configure(ManagedBass.Configuration.IOSMixAudio, 5);
+            // Set BASS_IOS_SESSION_DISABLE here to leave session configuration in our hands (see iOS project).
+            Bass.Configure(ManagedBass.Configuration.IOSSession, 16);
 
             // Always provide a default device. This should be a no-op, but we have asserts for this behaviour.
             Bass.Configure(ManagedBass.Configuration.IncludeDefaultDevice, true);