Wwise on iOS plays audio in background only when screen of device is on

Question

I am trying to run wwise in background on mobile devices. With Android there is no problem, but in iOS it is not working like expected. 

iOS has 2 audio session categories when background audio is possible: AudioSessionCategoryPlayback and AudioSessionCategoryPlayAndRecord. I tested with both. AudioSessionCategoryPlayAndRecord works as expected. When i set AudioSessionCategoryPlayback, i can leave the app and the audio continues to play. But when i lock the screen of the device, the audio stops and i get "AK Error: Voice Starvation". It looks like the audio output depends on the screen framerate or something. 

Device: iPhone 14 Pro,iPad Air 5th Gen

Wwise version: 2022.1.5.8242

What am i doing wrong. Is it a bug in wwise?

Comments

Did you manage to fix the problem? I am running into the same issue and have been trying to find a fix forever.
I also opened a topic but no one seems to be around to provide an explanation.

https://www.audiokinetic.com/qa/11747/wwise-to-play-music-when-screen-is-locked-and-dimmed

Answer 1

See the documentation regarding "Foreground/Background Transitions" on iOS: https://www.audiokinetic.com/fr/library/edge/?source=SDK&id=pg_ios_understanding_audio_session_and_its_concepts.html#ios_audio_events_mechanism_with_wwise

In short, the default audio session type (the value of the platform init setting AkAudioSessionCategoryOptions) on iOS is "AVAudioSessionCategorySoloAmbient", but only the "AkAudioSessionCategoryPlayback" allows audio to be played/recorded while the app is switched to the background. In addition to changing the default audio session type, you will also need to declare in your app's plist that it requires the authorization "App plays audio or streams audio/video using Airplay".