Different approach to re-creating the AVPlayer, and resetting the AVA…

…udioSession, when a track causes a failure.

Example/SwiftAudio/AudioController.swift

@@ -10,15 +10,21 @@ import Foundation
 import SwiftAudio
 
 
-class AudioController {
+class AudioController : AudioPlayerDelegate {
 
     static let shared = AudioController()
     let player: QueuedAudioPlayer
     let audioSessionController = AudioSessionController.shared
 
     let sources: [AudioItem] = [
         DefaultAudioItem(audioUrl: "https://p.scdn.co/mp3-preview/67b51d90ffddd6bb3f095059997021b589845f81?cid=d8a5ed958d274c2e8ee717e6a4b0971d", artist: "Bon Iver", title: "33 \"GOD\"", albumTitle: "22, A Million", sourceType: .stream, artwork: #imageLiteral(resourceName: "22AMI")),
-        DefaultAudioItem(audioUrl: "https://p.scdn.co/mp3-preview/081447adc23dad4f79ba4f1082615d1c56edf5e1?cid=d8a5ed958d274c2e8ee717e6a4b0971d", artist: "Bon Iver", title: "8 (circle)", albumTitle: "22, A Million", sourceType: .stream, artwork: #imageLiteral(resourceName: "22AMI")),
+
+        // This track has a problem on purpose. It has problematic image metadata.
+        // It causes the AVPlayerItem and AVPlayer to change to a status of `.failed`.
+        // After this happens, the AVPlayer must be recreated, 
+        // and the AVAudioSession category reset before playing other tracks.
+        DefaultAudioItem(audioUrl: "https://livestage.curiousmedia.com/public/pin/audio/problem-track-with-image-metadata.mp3", artist: "Fail", title: "Bad Image Metadata Failure", albumTitle: "Fail", sourceType: .stream, artwork: #imageLiteral(resourceName: "22AMI")),
+
         DefaultAudioItem(audioUrl: "https://p.scdn.co/mp3-preview/6f9999d909b017eabef97234dd7a206355720d9d?cid=d8a5ed958d274c2e8ee717e6a4b0971d", artist: "Bon Iver", title: "715 - CRΣΣKS", albumTitle: "22, A Million", sourceType: .stream, artwork: #imageLiteral(resourceName: "22AMI")),
         DefaultAudioItem(audioUrl: "https://p.scdn.co/mp3-preview/bf9bdd403c67fdbe06a582e7b292487c8cfd1f7e?cid=d8a5ed958d274c2e8ee717e6a4b0971d", artist: "Bon Iver", title: "____45_____", albumTitle: "22, A Million", sourceType: .stream, artwork: #imageLiteral(resourceName: "22AMI"))
     ]
@@ -35,8 +41,32 @@ class AudioController {
             .previous,
             .changePlaybackPosition
         ]
+
+        player.delegate = self
+
         try? audioSessionController.set(category: .playback)
         try? player.add(items: sources, playWhenReady: false)
     }
 
+    // MARK: - AudioPlayerDelegate
+
+    func audioPlayer(playerDidChangeState state: AudioPlayerState) {}
+
+    func audioPlayer(itemPlaybackEndedWithReason reason: PlaybackEndedReason) {}
+
+    func audioPlayer(secondsElapsed seconds: Double) {}
+
+    func audioPlayer(failedWithError error: Error?) {
+        print("AudioController failedWithError: ", error)
+    }
+
+    func audioPlayer(seekTo seconds: Int, didFinish: Bool) {}
+
+    func audioPlayer(didUpdateDuration duration: Double) {}
+
+    func audioPlayerResetAudioSession() {
+        // Reset the audio session category because there was a failure to play a track.
+        // If the category is not reset, it seems to behave like the default category
+        try? audioSessionController.set(category: .playback)
+    }
 }

SwiftAudio/Classes/AVPlayerWrapper/AVPlayerWrapper.swift

@@ -26,9 +26,9 @@ class AVPlayerWrapper: AVPlayerWrapperProtocol {
 
     // MARK: - Properties
 
-    let avPlayer: AVPlayer
-    let playerObserver: AVPlayerObserver
-    let playerTimeObserver: AVPlayerTimeObserver
+    var avPlayer: AVPlayer
+    var playerObserver: AVPlayerObserver
+    var playerTimeObserver: AVPlayerTimeObserver
     let playerItemNotificationObserver: AVPlayerItemNotificationObserver
     let playerItemObserver: AVPlayerItemObserver
 
@@ -192,11 +192,35 @@ class AVPlayerWrapper: AVPlayerWrapperProtocol {
         playerTimeObserver.unregisterForBoundaryTimeEvents()
         playerItemNotificationObserver.stopObservingCurrentItem()
 
+        //if the status of the current (about to be previous) item is .failed,
+        //we know that we need to reset
+        if (currentItem?.status == .failed) {
+            resetAfterFailure()
+        }
+
         if !soft {
             avPlayer.replaceCurrentItem(with: nil)
         }
     }
-
+
+    private func resetAfterFailure() {
+        //reset time observer just in case
+        playerTimeObserver.unregisterForPeriodicEvents()
+
+        // When AVPlayer status becomes .failed,
+        // the instance can no longer be used.
+        // A new instance must be created.
+        // https://developer.apple.com/documentation/avfoundation/avplayer/1388096-status
+        self.avPlayer = AVPlayer()
+
+        //observe the new player instance
+        self.playerObserver.setPlayer(player: self.avPlayer)
+        self.playerTimeObserver.setPlayer(player: self.avPlayer, periodicObserverTimeInterval: timeEventFrequency.getTime())
+        self.playerTimeObserver.registerForPeriodicTimeEvents()
+
+        //have delegates reset the audio session to whatever they intend to use
+        self.delegate?.AVWrapperResetAudioSession()
+    }    
 }
 
 extension AVPlayerWrapper: AVPlayerObserverDelegate {
@@ -236,6 +260,7 @@ extension AVPlayerWrapper: AVPlayerObserverDelegate {
 
         case .failed:
             self.delegate?.AVWrapper(failedWithError: avPlayer.error)
+            print("player status is .failed, will need to reset before playing again")
             break
 
         case .unknown:

SwiftAudio/Classes/AVPlayerWrapper/AVPlayerWrapperDelegate.swift

@@ -16,5 +16,5 @@ protocol AVPlayerWrapperDelegate: class {
     func AVWrapper(seekTo seconds: Int, didFinish: Bool)
     func AVWrapper(didUpdateDuration duration: Double)
     func AVWrapperItemDidPlayToEndTime()
-
+    func AVWrapperResetAudioSession()
 }

SwiftAudio/Classes/AudioPlayer.swift

@@ -25,6 +25,7 @@ public protocol AudioPlayerDelegate: class {
 
     func audioPlayer(didUpdateDuration duration: Double)
 
+    func audioPlayerResetAudioSession()
 }
 
 public class AudioPlayer: AVPlayerWrapperDelegate {
@@ -367,4 +368,7 @@ public class AudioPlayer: AVPlayerWrapperDelegate {
         self.delegate?.audioPlayer(itemPlaybackEndedWithReason: .playedUntilEnd)
     }
 
+    func AVWrapperResetAudioSession() {
+        self.delegate?.audioPlayerResetAudioSession()
+    }    
 }

SwiftAudio/Classes/Observer/AVPlayerObserver.swift

@@ -36,7 +36,7 @@ class AVPlayerObserver: NSObject {
         static let timeControlStatus = #keyPath(AVPlayer.timeControlStatus)
     }
 
-    let player: AVPlayer
+    var player: AVPlayer
     private let statusChangeOptions: NSKeyValueObservingOptions = [.new, .initial]
     private let timeControlStatusChangeOptions: NSKeyValueObservingOptions = [.new]
     var isObserving: Bool = false
@@ -54,6 +54,16 @@ class AVPlayerObserver: NSObject {
         }
     }
 
+    func setPlayer(player: AVPlayer) {
+        if self.isObserving {
+            self.player.removeObserver(self, forKeyPath: AVPlayerKeyPath.status, context: &AVPlayerObserver.context)
+            self.player.removeObserver(self, forKeyPath: AVPlayerKeyPath.timeControlStatus, context: &AVPlayerObserver.context)
+        }
+
+        self.player = player
+        self.isObserving = false
+    }
+
     /**
      Start receiving events from this observer.
      

SwiftAudio/Classes/Observer/AVPlayerTimeObserver.swift

@@ -27,7 +27,7 @@ class AVPlayerTimeObserver {
     var boundaryTimeStartObserverToken: Any?
     var periodicTimeObserverToken: Any?
 
-    private let player: AVPlayer
+    private var player: AVPlayer
 
     /// The frequence to receive periodic time events.
     /// Setting this to a new value will trigger a re-registering to the periodic events of the player.
@@ -45,6 +45,11 @@ class AVPlayerTimeObserver {
         self.player = player
         self.periodicObserverTimeInterval = periodicObserverTimeInterval
     }
+
+    func setPlayer(player: AVPlayer, periodicObserverTimeInterval: CMTime) {
+        self.player = player
+        self.periodicObserverTimeInterval = periodicObserverTimeInterval
+    }
 
     /**
      Will register for the AVPlayer BoundaryTimeEvents, to trigger start and complete events.