Estoy tratando de vivir los niveles de volumen usando AVCaptureDevice, etc., se compila y ejecuta, pero los valores parecen ser aleatorios y sigo recibiendo errores de desbordamiento también.

EDITAR:

¿También es normal que el rango RMS sea de 0 a aproximadamente 20000?

        if let audioCaptureDevice : AVCaptureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeAudio){



            try audioCaptureDevice.lockForConfiguration()

            let audioInput = try AVCaptureDeviceInput(device: audioCaptureDevice)
            audioCaptureDevice.unlockForConfiguration()

            if(captureSession.canAddInput(audioInput)){
                captureSession.addInput(audioInput)
                print("added input")
            }


            let audioOutput = AVCaptureAudioDataOutput()

            audioOutput.setSampleBufferDelegate(self, queue: GlobalUserInitiatedQueue)

            if(captureSession.canAddOutput(audioOutput)){
                captureSession.addOutput(audioOutput)
                print("added output")
            }


            //supposed to start session not on UI queue coz it takes a while
            dispatch_async(GlobalUserInitiatedQueue) {
                print("starting captureSession")
                self.captureSession.startRunning()
            }
        }

...

func captureOutput(captureOutput: AVCaptureOutput!, let didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {

    // Needs to be initialized somehow, even if we take only the address
    var audioBufferList = AudioBufferList(mNumberBuffers: 1,
        mBuffers: AudioBuffer(mNumberChannels: 1, mDataByteSize: 0, mData: nil))
    //this needs to be in method otherwise only runs 125 times?
    var blockBuffer: CMBlockBuffer?

    CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(
        sampleBuffer,
        nil,
        &audioBufferList,
        sizeof(audioBufferList.dynamicType),
        nil,
        nil,
        UInt32(kCMSampleBufferFlag_AudioBufferList_Assure16ByteAlignment),
        &buffer
    )



    let abl = UnsafeMutableAudioBufferListPointer(&audioBufferList)

    for buffer in abl{
        let samples = UnsafeMutableBufferPointer<Int16>(start: UnsafeMutablePointer(buffer.mData),
            count: Int(buffer.mDataByteSize)/sizeof(Int16))


        var sum:Int = 0
        for sample in samples {
            sum = sum + Int(sample*sample)

        }

        let rms = sqrt(Double(sum)/count)
    }