fix recursive polling logic

* update links

* update example app to show podcast, soundbite, and radio

Example/SwiftAudioPlayer/Base.lproj/Main.storyboard

@@ -72,8 +72,8 @@
                                 <rect key="frame" x="16" y="60" width="343" height="32"/>
                                 <segments>
                                     <segment title="Soundbite"/>
-                                    <segment title="Acquired"/>
-                                    <segment title="Y Combinator"/>
+                                    <segment title="Podcast"/>
+                                    <segment title="Radio"/>
                                 </segments>
                                 <connections>
                                     <action selector="audioSelected:" destination="vXZ-lx-hvc" eventType="valueChanged" id="oYE-yq-348"/>

Example/SwiftAudioPlayer/Model.swift

@@ -13,18 +13,18 @@ struct AudioInfo: Hashable {
     
     var urls: [URL] = [URL(string: "https://www.fesliyanstudios.com/musicfiles/2019-04-23_-_Trusted_Advertising_-_www.fesliyanstudios.com/15SecVersion2019-04-23_-_Trusted_Advertising_-_www.fesliyanstudios.com.mp3")!,
                        URL(string: "https://chtbl.com/track/18338/traffic.libsyn.com/secure/acquired/acquired_-_armrev_2.mp3?dest-id=376122")!,
-                       URL(string: "https://backtracks.fm/ycombinator/pr/0f685f72-29b1-11e9-9bcf-0ece7a7d2472/111---jake-klamka-and-kevin-hale---y-combinator.mp3?s=1&sd=1&u=1549423185")!]
+                       URL(string: "https://ice6.somafm.com/groovesalad-256-mp3")!]
     
     var url: URL {
         switch index {
         case 0:
-            return URL(string: "https://www.fesliyanstudios.com/musicfiles/2019-04-23_-_Trusted_Advertising_-_www.fesliyanstudios.com/15SecVersion2019-04-23_-_Trusted_Advertising_-_www.fesliyanstudios.com.mp3")!
+            return urls[0]
         case 1:
-            return URL(string: "https://chtbl.com/track/18338/traffic.libsyn.com/secure/acquired/acquired_-_armrev_2.mp3?dest-id=376122")!
+            return urls[1]
         case 2:
-            return URL(string: "https://backtracks.fm/ycombinator/pr/0f685f72-29b1-11e9-9bcf-0ece7a7d2472/111---jake-klamka-and-kevin-hale---y-combinator.mp3?s=1&sd=1&u=1549423185")!
+            return urls[2]
         default:
-            return URL(string: "https://www.fesliyanstudios.com/musicfiles/2019-04-23_-_Trusted_Advertising_-_www.fesliyanstudios.com/15SecVersion2019-04-23_-_Trusted_Advertising_-_www.fesliyanstudios.com.mp3")!
+            return urls[0]
         }
     }
     
@@ -33,9 +33,9 @@ struct AudioInfo: Hashable {
         case 0:
             return "Soundbite"
         case 1:
-            return "Acquired"
+            return "Podcast"
         case 2:
-            return "Y Combinator"
+            return "Radio"
         default:
             return "Soundbite"
         }

README.md

@@ -17,6 +17,7 @@ Thus, using [AudioToolbox](https://developer.apple.com/documentation/audiotoolbo
 1. Play locally saved audio with the same API
 1. Download audio
 1. Queue up downloaded and streamed audio for autoplay
+1. Uses only 1-2% CPU for optimal performance for the rest of your app
 1. You're able to install taps and any other AVAudioEngine features to do cool things like skipping silences
 
 ### Special Features
@@ -33,7 +34,7 @@ iOS 10.0 and higher.
 ### Running the Example Project
 
 1. Clone repo
-2. CD to directory
+2. CD to the `Example` folder where the Example app lives
 3. Run `pod install` in terminal
 4. Build and run
 

Source/Engine/AudioEngine.swift

@@ -173,6 +173,7 @@ class AudioEngine: AudioEngineProtocol {
         Timer.scheduledTimer(withTimeInterval: timeInterval, repeats: false) { [weak self] (timer: Timer) in
             guard let self = self else { return }
             guard self.playingStatus != .ended else {
+//                Log.test("END TIMER")
                 self.delegate = nil
                 return
             }

Source/Engine/AudioStreamEngine.swift

@@ -71,6 +71,7 @@ class AudioStreamEngine: AudioEngine {
     
     private var numberOfBuffersScheduledInTotal = 0 {
         didSet {
+//            Log.test(numberOfBuffersScheduledInTotal)
             Log.debug("number of buffers scheduled in total: \(numberOfBuffersScheduledInTotal)")
             if numberOfBuffersScheduledInTotal == 0 {
                 pause()
@@ -86,6 +87,7 @@ class AudioStreamEngine: AudioEngine {
     private var numberOfBuffersScheduledFromPoll = 0 {
         didSet {
             if numberOfBuffersScheduledFromPoll > MAX_POLL_BUFFER_COUNT {
+//                Log.test("🛑  🛑   STOP POLLING")
                 shouldPollForNextBuffer = false
             }
             
@@ -137,7 +139,7 @@ class AudioStreamEngine: AudioEngine {
         Log.info(url)
         super.init(url: url, delegate: delegate, engineAudioFormat: AudioEngine.defaultEngineAudioFormat)
         do {
-            converter = try AudioConverter(withRemoteUrl: url, toEngineAudioFormat: AudioEngine.defaultEngineAudioFormat)
+            converter = try AudioConverter(withRemoteUrl: url, toEngineAudioFormat: AudioEngine.defaultEngineAudioFormat, withPCMBufferSize: PCM_BUFFER_SIZE)
         } catch {
             delegate?.didError()
         }
@@ -165,8 +167,15 @@ class AudioStreamEngine: AudioEngine {
     private func pollForNextBuffer() {
         guard shouldPollForNextBuffer else { return }
         
+//        Log.test("POLL INIT")
+        pollForNextBufferRecursive()
+    }
+    
+    private func pollForNextBufferRecursive() {
+//        Log.test("POLL")
+        
         do {
-            var nextScheduledBuffer: AVAudioPCMBuffer! = try converter.pullBuffer(withSize: PCM_BUFFER_SIZE)
+            var nextScheduledBuffer: AVAudioPCMBuffer! = try converter.pullBuffer()
             numberOfBuffersScheduledFromPoll += 1
             numberOfBuffersScheduledInTotal += 1
             
@@ -174,16 +183,18 @@ class AudioStreamEngine: AudioEngine {
             queue.async { [weak self] in
                 if #available(iOS 11.0, *) {
                     // to make sure the pcm buffers are properly free'd from memory we need to nil them after the player has used them
-                    self?.playerNode.scheduleBuffer(nextScheduledBuffer, completionCallbackType: .dataRendered, completionHandler: { (_) in
+                    self?.playerNode.scheduleBuffer(nextScheduledBuffer, completionCallbackType: .dataConsumed, completionHandler: { (_) in
                         nextScheduledBuffer = nil
                         self?.numberOfBuffersScheduledInTotal -= 1
-                        self?.pollForNextBufferRecursionHelper()
+//                        Log.test("POLL DATA RENDERED")
+                        self?.pollForNextBufferRecursive()
                     })
                 } else {
                     self?.playerNode.scheduleBuffer(nextScheduledBuffer) {
                         nextScheduledBuffer = nil
                         self?.numberOfBuffersScheduledInTotal -= 1
-                        self?.pollForNextBufferRecursionHelper()
+//                        Log.test("POLL OLD")
+                        self?.pollForNextBufferRecursive()
                     }
                 }
             }
@@ -200,32 +211,6 @@ class AudioStreamEngine: AudioEngine {
         }
     }
     
-    private func pollForNextBufferRecursionHelper() {
-        do {
-            let nextScheduledBuffer = try converter.pullBuffer(withSize: PCM_BUFFER_SIZE)
-            Log.debug("processed buffer for engine of frame lengthL \(nextScheduledBuffer.frameLength)")
-            numberOfBuffersScheduledInTotal += 1
-            
-            queue.async { [weak self] in
-                self?.playerNode.scheduleBuffer(nextScheduledBuffer) {
-                    self?.numberOfBuffersScheduledInTotal -= 1
-                    self?.pollForNextBufferRecursionHelper()
-                }
-                
-            }
-            
-        } catch ConverterError.reachedEndOfFile {
-            Log.info(ConverterError.reachedEndOfFile.localizedDescription)
-        } catch ConverterError.notEnoughData {
-            shouldPollForNextBuffer = true
-            Log.debug(ConverterError.notEnoughData.localizedDescription)
-        } catch ConverterError.superConcerningShouldNeverHappen {
-            Log.error(ConverterError.superConcerningShouldNeverHappen.localizedDescription)
-        } catch {
-            Log.debug(error.localizedDescription)
-        }
-    }
-    
     private func updateNetworkBufferRange() { //for ui
         let range = converter.pollNetworkAudioAvailabilityRange()
         isPlayable = (numberOfBuffersScheduledInTotal >= MIN_BUFFERS_TO_BE_PLAYABLE && range.1 > 0) && predictedStreamDuration > 0

Source/Engine/Converter/AudioConverter.swift

@@ -36,8 +36,8 @@ import AudioToolbox
 protocol AudioConvertable {
     var engineAudioFormat: AVAudioFormat {get}
     
-    init(withRemoteUrl url: AudioURL, toEngineAudioFormat: AVAudioFormat) throws
-    func pullBuffer(withSize size: AVAudioFrameCount) throws -> AVAudioPCMBuffer
+    init(withRemoteUrl url: AudioURL, toEngineAudioFormat: AVAudioFormat, withPCMBufferSize size: AVAudioFrameCount) throws
+    func pullBuffer() throws -> AVAudioPCMBuffer
     func pollPredictedDuration() -> Duration?
     func pollNetworkAudioAvailabilityRange() -> (Needle, Duration)
     func seek(_ needle: Needle)
@@ -70,13 +70,20 @@ class AudioConverter: AudioConvertable {
     
     //From protocol
     public var engineAudioFormat: AVAudioFormat
+    let pcmBufferSize: AVAudioFrameCount
     
     //Field
     var converter: AudioConverterRef? //set by AudioConverterNew
     var currentAudioPacketIndex: AVAudioPacketCount = 0
     
-    required init(withRemoteUrl url: AudioURL, toEngineAudioFormat: AVAudioFormat) throws {
+    // use to store reference to the allocated buffers from the converter to properly deallocate them before the next packet is being converted
+    var converterBuffer: UnsafeMutableRawPointer?
+    var converterDescriptions: UnsafeMutablePointer<AudioStreamPacketDescription>?
+    
+    required init(withRemoteUrl url: AudioURL, toEngineAudioFormat: AVAudioFormat, withPCMBufferSize size: AVAudioFrameCount) throws {
         self.engineAudioFormat = toEngineAudioFormat
+        self.pcmBufferSize = size
+        
         do {
             parser = try AudioParser(withRemoteUrl: url, parsedFileAudioFormatCallback: {
                 [weak self] (fileAudioFormat: AVAudioFormat) in
@@ -108,17 +115,17 @@ class AudioConverter: AudioConvertable {
         }
     }
     
-    func pullBuffer(withSize size: AVAudioFrameCount) throws -> AVAudioPCMBuffer {
+    func pullBuffer() throws -> AVAudioPCMBuffer {
         guard let converter = converter else {
             Log.debug("reader_error trying to read before converter has been created")
             throw ConverterError.cannotCreatePCMBufferWithoutConverter
         }
         
-        guard let pcmBuffer = AVAudioPCMBuffer(pcmFormat: engineAudioFormat, frameCapacity: size) else {
+        guard let pcmBuffer = AVAudioPCMBuffer(pcmFormat: engineAudioFormat, frameCapacity: pcmBufferSize) else {
             Log.monitor(ConverterError.failedToCreatePCMBuffer.errorDescription as Any)
             throw ConverterError.failedToCreatePCMBuffer
         }
-        pcmBuffer.frameLength = size
+        pcmBuffer.frameLength = pcmBufferSize
         
         /**
          The whole thing is wrapped in queue.sync() because the converter listener
@@ -127,7 +134,7 @@ class AudioConverter: AudioConvertable {
          */
         return try queue.sync { () -> AVAudioPCMBuffer in
             let framesPerPacket = engineAudioFormat.streamDescription.pointee.mFramesPerPacket
-            var numberOfPacketsWeWantTheBufferToFill = size / framesPerPacket
+            var numberOfPacketsWeWantTheBufferToFill = pcmBuffer.frameLength / framesPerPacket
             
             let context = unsafeBitCast(self, to: UnsafeMutableRawPointer.self)
             let status = AudioConverterFillComplexBuffer(converter, ConverterListener, context, &numberOfPacketsWeWantTheBufferToFill, pcmBuffer.mutableAudioBufferList, nil)

Source/Engine/Converter/AudioConverterListener.swift

@@ -65,6 +65,10 @@ func ConverterListener(_ converter: AudioConverterRef, _ packetCount: UnsafeMuta
         return ReaderShouldNotHappenError
     }
     
+    if let lastBuffer = selfAudioConverter.converterBuffer {
+        lastBuffer.deallocate()
+    }
+    
     // Copy data over (note we've only processing a single packet of data at a time)
     var packet = audioPacket.1
     let packetByteCount = packet.count //this is not the count of an array
@@ -75,6 +79,12 @@ func ConverterListener(_ converter: AudioConverterRef, _ packetCount: UnsafeMuta
     })
     ioData.pointee.mBuffers.mDataByteSize = UInt32(packetByteCount)
     
+    selfAudioConverter.converterBuffer = ioData.pointee.mBuffers.mData
+    
+    if let lastDescription = selfAudioConverter.converterDescriptions {
+        lastDescription.deallocate()
+    }
+    
     // Handle packet descriptions for compressed formats (MP3, AAC, etc)
     let fileFormatDescription = fileAudioFormat.streamDescription.pointee
     if fileFormatDescription.mFormatID != kAudioFormatLinearPCM {
@@ -86,6 +96,8 @@ func ConverterListener(_ converter: AudioConverterRef, _ packetCount: UnsafeMuta
         outPacketDescriptions?.pointee?.pointee.mVariableFramesInPacket = 0
     }
     
+    selfAudioConverter.converterDescriptions = outPacketDescriptions?.pointee
+    
     packetCount.pointee = 1
     
     //we've successfully given a packet to the LPCM buffer now we can process the next audio packet

SwiftAudioPlayer.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'SwiftAudioPlayer'
-  s.version          = '4.0.0'
+  s.version          = '4.1.0'
   s.summary          = 'SwiftAudioPlayer is a Swift based audio player that can handle streaming from a remote location and audio manipulation.'
 
 # This description is used to generate tags and improve search results.