Sleep Timer Improvements: fade out 5s before pausing playback

CHANGELOG.md

@@ -2,6 +2,7 @@
 -----
 - Show the Up Next bar on the tab bar. [#1613]
 - Shake the device to restart Sleep Timer [#1627]
+- Playback fades out when finishing a sleep timer [#1629]
 
 7.62
 -----

podcasts.xcodeproj/project.pbxproj

@@ -549,6 +549,8 @@
 		8BAD6E5E2975ADB800DB7259 /* GoogleSignIn in Frameworks */ = {isa = PBXBuildFile; productRef = 8BAD6E5D2975ADB800DB7259 /* GoogleSignIn */; };
 		8BAD6E612975AFAA00DB7259 /* GoogleSocialLogin.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8BAD6E602975AFAA00DB7259 /* GoogleSocialLogin.swift */; };
 		8BB2E58B2A8AA02E00E93088 /* SharedConstants.swift in Sources */ = {isa = PBXBuildFile; fileRef = BD054A791E3EDEB300D9195B /* SharedConstants.swift */; };
+		8BB4AA632BD17EC10091480A /* FadeOutManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8BB4AA622BD17EC10091480A /* FadeOutManager.swift */; };
+		8BB4AA642BD17EC10091480A /* FadeOutManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8BB4AA622BD17EC10091480A /* FadeOutManager.swift */; };
 		8BB4AA662BD1A8040091480A /* sleep-timer-restarted-sound.mp3 in Resources */ = {isa = PBXBuildFile; fileRef = 8BB4AA652BD1A8040091480A /* sleep-timer-restarted-sound.mp3 */; };
 		8BB4AA672BD1A80E0091480A /* sleep-timer-restarted-sound.mp3 in Resources */ = {isa = PBXBuildFile; fileRef = 8BB4AA652BD1A8040091480A /* sleep-timer-restarted-sound.mp3 */; };
 		8BB55E3A28FEEE99001D1766 /* StoryShareableProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8BB55E3928FEEE99001D1766 /* StoryShareableProvider.swift */; };
@@ -2353,6 +2355,7 @@
 		8BAB8B2E299ABC8200B8404C /* SearchResultsViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SearchResultsViewController.swift; sourceTree = "<group>"; };
 		8BAD2EB32AEE9620006264B3 /* PaidStoryWallView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PaidStoryWallView.swift; sourceTree = "<group>"; };
 		8BAD6E602975AFAA00DB7259 /* GoogleSocialLogin.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GoogleSocialLogin.swift; sourceTree = "<group>"; };
+		8BB4AA622BD17EC10091480A /* FadeOutManager.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FadeOutManager.swift; sourceTree = "<group>"; };
 		8BB4AA652BD1A8040091480A /* sleep-timer-restarted-sound.mp3 */ = {isa = PBXFileReference; lastKnownFileType = audio.mp3; path = "sleep-timer-restarted-sound.mp3"; sourceTree = "<group>"; };
 		8BB55E3928FEEE99001D1766 /* StoryShareableProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StoryShareableProvider.swift; sourceTree = "<group>"; };
 		8BC060072AB1FA0400A4FEC6 /* PlayEpisodeIntent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PlayEpisodeIntent.swift; sourceTree = "<group>"; };
@@ -4934,6 +4937,7 @@
 				BDF15A3D1B54E053000EC323 /* PlaybackManager.swift */,
 				BDF15A3F1B54E064000EC323 /* PlaybackQueue.swift */,
 				BDF15A451B54E21B000EC323 /* PlaybackEffects.swift */,
+				8BB4AA622BD17EC10091480A /* FadeOutManager.swift */,
 				8B1B782A2BC7104000DC3373 /* SleepTimerManager.swift */,
 				BD44A4442302DAC6004F55B2 /* CommonUpNextItem.swift */,
 				BD2219F0253EAEAF000025BE /* PlaybackCatchUpHelper.swift */,
@@ -8719,6 +8723,7 @@
 				C7BDECB52A15327000BECF02 /* PatronUnlockButton.swift in Sources */,
 				BDA206601BB3D4D600D38389 /* DownloadsViewController.swift in Sources */,
 				407502B6240DCBF200437528 /* NetworkUtils+Helpers.swift in Sources */,
+				8BB4AA632BD17EC10091480A /* FadeOutManager.swift in Sources */,
 				C741D9D428ADBA23006CFBE7 /* AppLifecyleAnalytics.swift in Sources */,
 				BDD84CE527CC9353001C078B /* ChoosePodcastFolderModel.swift in Sources */,
 				8BA198842AE0205900B66568 /* CompletionRateStory.swift in Sources */,
@@ -9487,6 +9492,7 @@
 				BDE48A242410D0D400ECA6CA /* UserEpisodeManager.swift in Sources */,
 				461C46CE274D9E400003D3A9 /* LocalizationHelpers.swift in Sources */,
 				C7252863299B353A00A582C3 /* BookmarkManager.swift in Sources */,
+				8BB4AA642BD17EC10091480A /* FadeOutManager.swift in Sources */,
 				46D88AB727DF97CA00F3BC43 /* PodcastsListView.swift in Sources */,
 				463FCE7D27BEA90B00E5AF89 /* WatchInterfaceType.swift in Sources */,
 				46CD891327E222B20046A9FB /* FilterEpisodeListView.swift in Sources */,

podcasts/DefaultPlayer.swift

@@ -111,6 +111,8 @@ class DefaultPlayer: PlaybackProtocol, Hashable {
         performSetPlaybackRate()
         jumpToStartingPosition()
 
+        player?.volume = 1
+
         completion?()
     }
 
@@ -681,4 +683,10 @@ class DefaultPlayer: PlaybackProtocol, Hashable {
         episodeArtwork.loadEmbeddedImage(asset: asset, podcastUuid: podcastUuid, episodeUuid: episodeUuid)
         #endif
     }
+
+    // MARK: - Volume
+
+    func setVolume(_ volume: Float) {
+        player?.volume = volume
+    }
 }

podcasts/EffectsPlayer.swift

@@ -25,6 +25,8 @@ class EffectsPlayer: PlaybackProtocol, Hashable {
     private var timePitch: AVAudioUnitTimePitch?
     private var playbackSpeed = 0 as Double // AVAudioUnitTimePitch seems to not like us querying the rate sometimes, so store that as a separate variable
 
+    private var audioMixerNode: AVAudioMixerNode?
+
     // for volume boost
     private var highPassFilter: AVAudioUnitEffect?
     private var dynamicsProcessor: AVAudioUnitEffect?
@@ -84,6 +86,9 @@ class EffectsPlayer: PlaybackProtocol, Hashable {
             strongSelf.effects = PlaybackManager.shared.effects()
             strongSelf.playBufferManager = PlayBufferManager()
 
+            strongSelf.audioMixerNode = strongSelf.createAudioMixerNode()
+            strongSelf.engine?.attach(strongSelf.audioMixerNode!)
+
             // volume boost effects
             strongSelf.highPassFilter = strongSelf.createHighPassUnit()
             strongSelf.engine?.attach(strongSelf.highPassFilter!)
@@ -137,7 +142,8 @@ class EffectsPlayer: PlaybackProtocol, Hashable {
                 format = strongSelf.audioFile!.processingFormat
             }
 
-            strongSelf.engine?.connect(strongSelf.player!, to: strongSelf.timePitch!, format: format)
+            strongSelf.engine?.connect(strongSelf.player!, to: strongSelf.audioMixerNode!, format: format)
+            strongSelf.engine?.connect(strongSelf.audioMixerNode!, to: strongSelf.timePitch!, format: format)
             strongSelf.engine?.connect(strongSelf.timePitch!, to: strongSelf.highPassFilter!, format: format)
             strongSelf.engine?.connect(strongSelf.highPassFilter!, to: strongSelf.dynamicsProcessor!, format: format)
             strongSelf.engine?.connect(strongSelf.dynamicsProcessor!, to: strongSelf.peakLimiter!, format: format)
@@ -432,6 +438,10 @@ class EffectsPlayer: PlaybackProtocol, Hashable {
         }
     }
 
+    private func createAudioMixerNode() -> AVAudioMixerNode {
+        return AVAudioMixerNode()
+    }
+
     private func createTimePitchUnit() -> AVAudioUnitTimePitch {
         var componentDescription = AudioComponentDescription()
         componentDescription.componentType = kAudioUnitType_FormatConverter
@@ -477,4 +487,10 @@ class EffectsPlayer: PlaybackProtocol, Hashable {
     func hash(into hasher: inout Hasher) {
         hasher.combine(ObjectIdentifier(self))
     }
+
+    // MARK: - Volume
+
+    func setVolume(_ volume: Float) {
+        audioMixerNode?.outputVolume = volume
+    }
 }

podcasts/FadeOutManager.swift

@@ -0,0 +1,47 @@
+import Foundation
+
+class FadeOutManager {
+    weak var player: PlaybackProtocol?
+
+    private var timer: Timer?
+
+    private let volumeChangesPerSecond = 30.0
+    private var currentChange = 0.0
+    private var fadeDuration = 5.0
+    private let fadeVelocity = 2.0
+    private let fromVolume = 1.0
+    private let toVolume = 0.0
+    private var totalNumberOfVolumeChanges = 0.0
+    private lazy var timerDelay = 1.0 / volumeChangesPerSecond
+
+
+    /// Performs a fade out on the given `PlaybackProtocol` by using a logarithmic algorithm
+    /// This way the final results is smooth 🧈 to the human's hearing 👂
+    /// - Parameter duration: the duration of the fade out effect
+    func fadeOut(duration: TimeInterval) {
+        fadeDuration = duration
+        currentChange = 0
+        totalNumberOfVolumeChanges = fadeDuration * volumeChangesPerSecond
+        timer = Timer.scheduledTimer(withTimeInterval: TimeInterval(timerDelay), repeats: true) { [weak self] _ in
+            guard let self,
+                  currentChange < totalNumberOfVolumeChanges else {
+                self?.timer?.invalidate()
+                return
+            }
+
+            let normalizedTime = (currentChange / totalNumberOfVolumeChanges).betweenZeroAndOne
+            let volumeMultiplier = pow(M_E, -fadeVelocity * normalizedTime) * (1 - normalizedTime)
+            let newVolume = toVolume - (toVolume - fromVolume) * volumeMultiplier
+
+            player?.playing() == true ? player?.setVolume(Float(newVolume)) : timer?.invalidate()
+
+            currentChange += 1
+        }
+    }
+}
+
+private extension Double {
+    var betweenZeroAndOne: Double {
+        max(0, min(1, self))
+    }
+}

podcasts/GoogleCastPlayer.swift

@@ -122,4 +122,10 @@ class GoogleCastPlayer: PlaybackProtocol {
     func internalPlayerForVideoPlayback() -> AVPlayer? {
         nil
     }
+
+    // MARK: - Volume
+
+    func setVolume(_ volume: Float) {
+        // not supported
+    }
 }

podcasts/PlaybackManager.swift

@@ -1368,6 +1368,10 @@ class PlaybackManager: ServerPlaybackDelegate {
 
         // here (as above) we're assuming that in general the timer fires around once a second. Might have to investigate this though as it might not always be the case
         if sleepTimeRemaining >= 0 {
+            if sleepTimeRemaining == sleepTimerManager.sleepTimerFadeDuration {
+                sleepTimerManager.performFadeOut(player: player)
+            }
+
             sleepTimeRemaining = sleepTimeRemaining - updateTimerInterval
 
             if sleepTimeRemaining < 0 {

podcasts/PlaybackProtocol.swift

@@ -31,6 +31,8 @@ import PocketCastsDataModel
     func interruptionDidStart()
 
     func internalPlayerForVideoPlayback() -> AVPlayer?
+
+    func setVolume(_ volume: Float)
 }
 
 enum PlaybackError: Error {

podcasts/SleepTimerManager.swift

@@ -7,6 +7,10 @@ class SleepTimerManager {
 
     private let backgroundShakeObserver: BackgroundShakeObserver
 
+    let sleepTimerFadeDuration = 5.seconds
+
+    private lazy var fadeOutManager = FadeOutManager()
+
     private lazy var tonePlayer: AVAudioPlayer? = {
         guard let url = Bundle.main.url(forResource: "sleep-timer-restarted-sound", withExtension: "mp3") else {
             FileLog.shared.addMessage("[Sleep Timer] Unable to create tone player because the sound file is missing from the bundle.")
@@ -76,6 +80,11 @@ class SleepTimerManager {
         }
     }
 
+    func performFadeOut(player: PlaybackProtocol) {
+        fadeOutManager.player = player
+        fadeOutManager.fadeOut(duration: sleepTimerFadeDuration)
+    }
+
     private func observePlaybackEndAndReactivateTime() {
         NotificationCenter.default.addObserver(self, selector: #selector(playbackTrackChanged), name: Constants.Notifications.playbackTrackChanged, object: nil)
     }