problems with WebRTC iOS audio_device when doing a StartPlayback while already playing audio

[tom mcguinness]

I am working on a VoIP app that incorporates a SIP signalling engine and uses webrtc for the media. For calls local to our own network we play a ringback tone out through the speaker while the call is being put through.

What I am experiencing are some low level errors coming from the iOS audio system as soon as the SIP engine connects the media and does a StartPlayback. I have traced the problem down to a failure to AudioOutputUnitStart() in audio_device_ios.cc.  For now we are using webrtc's media engine as-is without any customizations of our own. 

If we make the call without playing ringback locally then these errors do not happen and our media streams are ok. I am no iOS audio programming expert and before burying my head too deeply into the iOS audio programming reference just looking for a few quick pointers from anyone who might have battled this before. I am guessing that I am missing some key audio unit or session property either higher up in the app or in the webrtc audio device that prevents simultaneous access to the iOS audio device..

These are the messages that are seen on the console (last one is from our own app)

18:24:42.839 ERROR:     [0x404f000] 1207: AUIOClient_StartIO failed (560034163)

18:24:42.843 ERROR:     [0x4b85000] >aurioc> 1455: AURemoteIO@0x16363a20: IOThread exiting with error 0x10004006

VoEBase::StartPlayout failed [VE_AUDIO_DEVICE_MODULE_ERROR 10028]

Thanks,

Tom

[Sonu Joshi]

Hi Tom,

I am also facing the same issue. Did you find any reason why this happening.?

What i found when the audio category is set to AVAudioSessionCategoryPlayback then AUIOClient_StartIO fails with error (560034163). If I use the different category  AVAudioSessionCategoryPlayAndRecord it works fine.

Please respond if you found any solution.

Thanks

Sonu

[Beck Lee]

The  same way as your operation , “AUIOClient_StartIO failed (-66637)” occurred to me. 

在 2014年3月19日星期三 UTC+8下午4:05:06，Sonu Joshi写道：