swift - 音频引擎仅在运行 iOS 10 的设备(iphone 6s)上失败，在所有模拟器设备或真实设备上运行良好，直到 iphone 6s

Question

我尝试将效果添加到音频文件，它在 iOS 9 上有效，但在 iOS10 中它仅在 iphone 6s 中失败，在旧设备上运行，在模拟器中运行良好，我的信息中确实有隐私使用说明。用于照片、相机和 microfon 的 plist 文件我确实在 audioEngine.mainMixerNode.installTapOnBus 线上收到输卵管错误

2016-09-21 13:08:20.109701 $$$$[557:86076] [central] 54:   ERROR:    [0x16e34f000] >avae> AVAudioNode.mm:751: AUSetFormat: error -10865 
2016-09-21 13:08:20.110111 Tell Your Story[557:86076] *** Terminating app due to uncaught exception 'com.apple.coreaudio.avfaudio', reason: 'error -10865'

我的音频添加效果函数

   private fund addEffetToAudioFile(pitch: Float, rate: Float, reverb: Float, echo: Float) { // Initialize variables
    audioEngine = AVAudioEngine()
    audioPlayerNode = AVAudioPlayerNode()
    audioEngine.attachNode(audioPlayerNode)

    // Setting the pitch
    let pitchEffect = AVAudioUnitTimePitch()
    pitchEffect.pitch = pitch
    audioEngine.attachNode(pitchEffect)

    // Setting the platback-rate
    let playbackRateEffect = AVAudioUnitVarispeed()
    playbackRateEffect.rate = rate
    audioEngine.attachNode(playbackRateEffect)

    // Setting the reverb effect
    let reverbEffect = AVAudioUnitReverb()
    reverbEffect.loadFactoryPreset(AVAudioUnitReverbPreset.Cathedral)
    reverbEffect.wetDryMix = reverb
    audioEngine.attachNode(reverbEffect)

    // Setting the echo effect on a specific interval
    let echoEffect = AVAudioUnitDelay()
    echoEffect.delayTime = NSTimeInterval(echo)
    audioEngine.attachNode(echoEffect)

    // Chain all these up, ending with the output
    audioEngine.connect(audioPlayerNode, to: playbackRateEffect, format: nil)
    audioEngine.connect(playbackRateEffect, to: pitchEffect, format: nil)
    audioEngine.connect(pitchEffect, to: reverbEffect, format: nil)
    audioEngine.connect(reverbEffect, to: echoEffect, format: nil)
    audioEngine.connect(echoEffect, to: audioEngine.mainMixerNode, format: nil)

    // Good practice to stop before starting
    audioPlayerNode.stop()

    // Play the audio file
    if (audioEngine != nil) {
        audioEngine?.stop()
    }

    do {
        audioFile = try AVAudioFile(forReading: self.recordedAudioURL)
    } catch {
        print("Error: Can't create audio file")
        self.showAlert(TYSAudioEditorHelper.Alerts.AudioFileError, message: String(error))
        return
    }

    audioPlayerNode.scheduleFile(audioFile, atTime: nil, completionHandler: {
        print("Complete")
    })

    try! audioEngine.start()

    let dirPaths: AnyObject = NSSearchPathForDirectoriesInDomains( NSSearchPathDirectory.DocumentDirectory,  NSSearchPathDomainMask.UserDomainMask, true)[0]
    let tmpFileUrl: NSURL = NSURL.fileURLWithPath(dirPaths.stringByAppendingPathComponent(kOutputSoundWithEffectFileName))
    do {
        self.newAudio = try AVAudioFile(forWriting: tmpFileUrl, settings:[
            AVFormatIDKey: NSNumber(unsignedInt:kAudioFormatMPEG4AAC_HE),
            AVEncoderAudioQualityKey : AVAudioQuality.Medium.rawValue,
            AVEncoderBitRateKey : 12800,
            AVNumberOfChannelsKey: 2,
            AVSampleRateKey : 44100.0
            ])

     /*Error in this line*/   audioEngine.mainMixerNode.installTapOnBus(0, bufferSize: 2048, format: audioEngine.mainMixerNode.inputFormatForBus(1)) { (buffer: AVAudioPCMBuffer!, time: AVAudioTime!) -> Void  in
            print(self.newAudio.length)
            if (self.newAudio.length) < (self.audioFile.length) {
                //Let us know when to stop saving the file, otherwise saving infinitely
                do {
                    try self.newAudio.writeFromBuffer(buffer)
                } catch {
                    print("Problem Writing Buffer")
                }
            } else {
                self.audioEngine.mainMixerNode.removeTapOnBus(0)
                //if we dont remove it, will keep on tapping infinitely
                self.newAudio = nil
                if (self.audioEngine != nil) {
                    self.audioEngine?.stop()
                }
                self.removeOldFileIfExist(self.kOriginalVideoSoundFileName)
                self.saveAudioFileInVideo(tmpFileUrl)
            }
        }
    } catch {
        print("Problem")
    }

    do {
        try audioEngine.start()
    } catch {
        showAlert(TYSAudioEditorHelper.Alerts.AudioEngineError, message: String(error))
        return
    }

    // play the recording!
    audioPlayerNode.play()
}

Answer 1

根据 https://developer.apple.com/reference/audiotoolbox/1584138-anonymous/kaudiouniterr_propertynotwritable?language=objc那个错误是

kAudioUnitErr_PropertyNotWritable = -10865

根据 https://developer.apple.com/reference/avfoundation/avaudionode/1387122-installtap

format: If non-nil, attempts to apply this as the format of the specified output bus. This should only be done when attaching to an output bus which is not connected to another node; an error will result otherwise. The tap and connection formats (if non-nil) on the specified bus should be identical. Otherwise, the latter operation will override any previously set format. For AVAudioOutputNode, tap format must be specified as nil.

所以可能是以下之一:

1. mainMixerNode 已经连接到另一个节点，所以你需要在安装 tap 之前断开它们

2. mainMixerNode是一个AVAudioOutputNode，所以这个参数需要传入nil