Callkit and Webrtc no audio when accept call from locked screen

Question

I'm trying to make callkit work with webrtc on incoming call, but when I receive call and accept it from locked screen there are no sound untill I run the app in the foreground mode. I've configured audiosession send notification to RTCAudioSession, but it doesn't work. Do you have some workarounds?

      func configureAudioSession() {

        let sharedSession = AVAudioSession.sharedInstance()
        do {
            try sharedSession.setCategory(AVAudioSessionCategoryPlayAndRecord, mode: AVAudioSessionModeVideoChat, options: .mixWithOthers)
            try sharedSession.setMode(AVAudioSessionModeVideoChat)
//            try sharedSession.setAggregatedIOPreference(AVAudioSessionIOType.aggregated)
        } catch {
            debugPrint("Failed to configure `AVAudioSession`")
        }
    }

    func handleIncomingCall(spaceName:String) {
        if callUUID != nil {
            oldCallUUID = callUUID
        }
        callUUID = UUID()
        print("CallManager handle uuid = \(callUUID?.description)")
        let update = CXCallUpdate()
        update.hasVideo = true
        update.remoteHandle = CXHandle(type: .generic, value: spaceName)
        self.configureAudioSession()
        provider?.reportNewIncomingCall(with: callUUID!, update: update, completion: { error in
            print("CallManager report new incoming call completion")
        })
    }

 func provider(_ provider: CXProvider, didActivate audioSession: AVAudioSession) {
        print("CallManager didActivate")
        RTCAudioSession.sharedInstance().audioSessionDidActivate(audioSession)
        RTCAudioSession.sharedInstance().isAudioEnabled = true
        self.callDelegate?.callIsAnswered()
    }

    func provider(_ provider: CXProvider, didDeactivate audioSession: AVAudioSession) {
        print("CallManager didDeactivate")
        RTCAudioSession.sharedInstance().audioSessionDidDeactivate(audioSession)
        RTCAudioSession.sharedInstance().isAudioEnabled = false
    }

Answer 1

Okay, I've found what the cause of an issue. In IOS 12 there is a problem with webrtc, when you start webrtc from locked screen and trying to get access to camera - the output volume breaks, so the solution is to check if the screen is Active or not, and if not - do not request and add local RTCVideoTrack into your RTCStream.