AVAudioRecorder grabar audio de secuencia

Tengo una aplicación que reproduce audio de transmisión. ¿Cómo puedo grabar audio de transmisión de AVPlayer usando AVAudioRecorder (o algo así?). Gracias.

Swift 3+ Aquí hay un simple VC que salvará la session de audio en documentos dir (audio.aac)

import UIKit import AVFoundation class ViewController: UIViewController { var audioRecorder: AVAudioRecorder? override func viewDidLoad() { super.viewDidLoad() verifyRecordPermission() } @IBAction func recordButonAction(_ sender: UIButton) { if audioRecorder?.isRecording == true { audioRecorder?.stop() sender.setTitle("Record", for: .normal) } else { startRecording() sender.setTitle("Stop", for: .normal) } } func verifyRecordPermission() { let permission = AVAudioSession.shanetworkingInstance().recordPermission() switch permission { case .denied: print("recording not allowed") case .granted: print("recording allowed") default: AVAudioSession.shanetworkingInstance().requestRecordPermission() { (granted) -> Void in print("recording granted:\(granted)") } } } func startRecording() { guard AVAudioSession.shanetworkingInstance().recordPermission() == .granted else { return } let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] let audioUrl = URL(fileURLWithPath: "\(documentsPath)/audio.aac") let session = AVAudioSession.shanetworkingInstance() do { try session.setCategory(AVAudioSessionCategoryRecord) try session.setActive(true) try audioRecorder = AVAudioRecorder(url: audioUrl, settings: [AVFormatIDKey: Int(kAudioFormatMPEG4AAC), AVSampleRateKey: 24000.0, AVNumberOfChannelsKey: 1 as NSNumber, AVEncoderAudioQualityKey: AVAudioQuality.high.rawValue]) } catch { // handle error... return } guard let audioRecorder = audioRecorder else { return } audioRecorder.prepareToRecord() audioRecorder.record() } func stop(session: AVAudioSession = AVAudioSession.shanetworkingInstance()) { audioRecorder?.stop() audioRecorder = nil do { try session.setActive(false) } catch { // handle session errors } } }