Garther audio concerns, clean up session when done

- sync speakerphone state manipulated from system call screen
  - Revert audio session after call failure, ensures media plays out of
    speaker after placing a failing call.
  - Replace notification with delegate pattern since we're already using
    delegate pattern here.
- Fixes voiceover accessibility after voice memo
- Avoid audio blip after pressing hangup
- Rename CallAudioSession -> OWSAudioSession
  Going to start using it for other non-call things since we want to
  gather all our audio session concerns.
- Resume background audio when done playing video
  - Extract OWSVideoPlayer which ensures audio is in proper state before
    playback
  - Move recording session logic to shared OWSAudioSession
  - Deactivate audio session when complete

// FREEBIE

Signal.xcodeproj/project.pbxproj

@@ -307,9 +307,10 @@
 		45DF5DF21DDB843F00C936C7 /* CompareSafetyNumbersActivity.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45DF5DF11DDB843F00C936C7 /* CompareSafetyNumbersActivity.swift */; };
 		45E5A6991F61E6DE001E4A8A /* MarqueeLabel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45E5A6981F61E6DD001E4A8A /* MarqueeLabel.swift */; };
 		45E7A6A81E71CA7E00D44FB5 /* DisplayableTextFilterTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45E7A6A61E71CA7E00D44FB5 /* DisplayableTextFilterTest.swift */; };
-		45F170AC1E2F0351003FC1F2 /* CallAudioSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170AB1E2F0351003FC1F2 /* CallAudioSession.swift */; };
 		45F170BB1E2FC5D3003FC1F2 /* CallAudioService.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170BA1E2FC5D3003FC1F2 /* CallAudioService.swift */; };
 		45F170D61E315310003FC1F2 /* Weak.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170D51E315310003FC1F2 /* Weak.swift */; };
+		45F59A082028E4FB00E8D2B0 /* OWSAudioSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170AB1E2F0351003FC1F2 /* OWSAudioSession.swift */; };
+		45F59A0A2029140500E8D2B0 /* OWSVideoPlayer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F59A092029140500E8D2B0 /* OWSVideoPlayer.swift */; };
 		45F659731E1BD99C00444429 /* CallKitCallUIAdaptee.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F659721E1BD99C00444429 /* CallKitCallUIAdaptee.swift */; };
 		45F659821E1BE77000444429 /* NonCallKitCallUIAdaptee.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F659811E1BE77000444429 /* NonCallKitCallUIAdaptee.swift */; };
 		45FBC5C81DF8575700E9B410 /* CallKitCallManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45FBC59A1DF8575700E9B410 /* CallKitCallManager.swift */; };
@@ -855,11 +856,12 @@
 		45E2E91E1E13EE3500457AA0 /* OWSCallNotificationsAdaptee.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; lineEnding = 0; name = OWSCallNotificationsAdaptee.h; path = UserInterface/OWSCallNotificationsAdaptee.h; sourceTree = "<group>"; xcLanguageSpecificationIdentifier = xcode.lang.objcpp; };
 		45E5A6981F61E6DD001E4A8A /* MarqueeLabel.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MarqueeLabel.swift; sourceTree = "<group>"; };
 		45E7A6A61E71CA7E00D44FB5 /* DisplayableTextFilterTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DisplayableTextFilterTest.swift; sourceTree = "<group>"; };
-		45F170AB1E2F0351003FC1F2 /* CallAudioSession.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CallAudioSession.swift; sourceTree = "<group>"; };
+		45F170AB1E2F0351003FC1F2 /* OWSAudioSession.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OWSAudioSession.swift; sourceTree = "<group>"; };
 		45F170B31E2F0A6A003FC1F2 /* RTCAudioSession.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RTCAudioSession.h; sourceTree = "<group>"; };
 		45F170BA1E2FC5D3003FC1F2 /* CallAudioService.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CallAudioService.swift; sourceTree = "<group>"; };
 		45F170D51E315310003FC1F2 /* Weak.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Weak.swift; sourceTree = "<group>"; };
 		45F3AEB51DFDE7900080CE33 /* AvatarImageView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AvatarImageView.swift; sourceTree = "<group>"; };
+		45F59A092029140500E8D2B0 /* OWSVideoPlayer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OWSVideoPlayer.swift; sourceTree = "<group>"; };
 		45F659721E1BD99C00444429 /* CallKitCallUIAdaptee.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CallKitCallUIAdaptee.swift; sourceTree = "<group>"; };
 		45F659811E1BE77000444429 /* NonCallKitCallUIAdaptee.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = NonCallKitCallUIAdaptee.swift; sourceTree = "<group>"; };
 		45FBC59A1DF8575700E9B410 /* CallKitCallManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CallKitCallManager.swift; sourceTree = "<group>"; };
@@ -1200,6 +1202,7 @@
 				346129921FD1E30000532771 /* migrations */,
 				347850671FD9B78A007B8332 /* NoopCallMessageHandler.swift */,
 				347850681FD9B78A007B8332 /* NoopNotificationsManager.swift */,
+				45F170AB1E2F0351003FC1F2 /* OWSAudioSession.swift */,
 				346129561FD1D74B00532771 /* Release.h */,
 				346129571FD1D74B00532771 /* Release.m */,
 				346129581FD1D74B00532771 /* SignalKeyingStorage.h */,
@@ -1587,6 +1590,7 @@
 				34CA1C281F7164F700E51C51 /* MediaMessageView.swift */,
 				45BC829C1FD9C4B400011CF3 /* ShareViewDelegate.swift */,
 				453034AA200289F50018945D /* VideoPlayerView.swift */,
+				45F59A092029140500E8D2B0 /* OWSVideoPlayer.swift */,
 			);
 			path = attachments;
 			sourceTree = "<group>";
@@ -1699,7 +1703,6 @@
 				45FBC5D01DF8592E00E9B410 /* SignalCall.swift */,
 				458DE9D51DEE3FD00071BB03 /* PeerConnectionClient.swift */,
 				4574A5D51DD6704700C6B692 /* CallService.swift */,
-				45F170AB1E2F0351003FC1F2 /* CallAudioSession.swift */,
 				45F170BA1E2FC5D3003FC1F2 /* CallAudioService.swift */,
 				452C468E1E427E200087B011 /* OutboundCallInitiator.swift */,
 			);
@@ -2768,6 +2771,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				45F59A0A2029140500E8D2B0 /* OWSVideoPlayer.swift in Sources */,
 				344F249B200FD03300CFB4F4 /* SharingThreadPickerViewController.m in Sources */,
 				45194F951FD7216600333B2C /* TSUnreadIndicatorInteraction.m in Sources */,
 				45BE4EA22012AD2000935E59 /* DisappearingTimerConfigurationView.swift in Sources */,
@@ -2831,6 +2835,7 @@
 				451F8A481FD715BA005CB9DA /* OWSContactAvatarBuilder.m in Sources */,
 				346129A61FD1F09100532771 /* OWSContactsManager.m in Sources */,
 				346129D21FD2085A00532771 /* CommonStrings.swift in Sources */,
+				45F59A082028E4FB00E8D2B0 /* OWSAudioSession.swift in Sources */,
 				34612A071FD7238600532771 /* OWSContactsSyncing.m in Sources */,
 				346129DF1FD5C02A00532771 /* LockInteractionController.m in Sources */,
 				451F8A471FD715BA005CB9DA /* OWSAvatarBuilder.m in Sources */,
@@ -2926,7 +2931,6 @@
 				34330AA31E79686200DF2FB9 /* OWSProgressView.m in Sources */,
 				34CA1C271F7156F300E51C51 /* MessageDetailViewController.swift in Sources */,
 				34D5CCA91EAE3D30005515DB /* AvatarViewHelper.m in Sources */,
-				45F170AC1E2F0351003FC1F2 /* CallAudioSession.swift in Sources */,
 				34D1F0B71F87F8850066283D /* OWSGenericAttachmentView.m in Sources */,
 				34B3F8801E8DF1700035BE1A /* InviteFlow.swift in Sources */,
 				34B3F8871E8DF1700035BE1A /* NotificationSettingsViewController.m in Sources */,

Signal/src/ViewControllers/CallViewController.swift

@@ -10,7 +10,7 @@ import SignalMessaging
 
 // TODO: Add category so that button handlers can be defined where button is created.
 // TODO: Ensure buttons enabled & disabled as necessary.
-class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
+class CallViewController: OWSViewController, CallObserver, CallServiceObserver, CallAudioServiceDelegate {
 
     let TAG = "[CallViewController]"
 
@@ -140,6 +140,9 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
         self.call = call
         self.thread = TSContactThread.getOrCreateThread(contactId: call.remotePhoneNumber)
         super.init(nibName: nil, bundle: nil)
+
+        assert(callUIAdapter.audioService.delegate == nil)
+        callUIAdapter.audioService.delegate = self
         observeNotifications()
     }
 
@@ -148,10 +151,6 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
                                                selector:#selector(didBecomeActive),
                                                name:NSNotification.Name.OWSApplicationDidBecomeActive,
                                                object:nil)
-
-        NotificationCenter.default.addObserver(forName: CallAudioServiceSessionChanged, object: nil, queue: nil) { [weak self] _ in
-            self?.didChangeAudioSession()
-        }
     }
 
     deinit {
@@ -379,21 +378,6 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
         ])
     }
 
-    func didChangeAudioSession() {
-        AssertIsOnMainThread()
-
-        // Which sources are available depends on the state of your Session.
-        // When the audio session is not yet in PlayAndRecord none are available
-        // Then if we're in speakerphone, bluetooth isn't available. 
-        // So we acrew all possible audio sources in a set, and that list lives as longs as the CallViewController
-        // The downside of this is that if you e.g. unpair your bluetooth mid call, it will still appear as an option
-        // until your next call.
-        // FIXME: There's got to be a better way, but this is where I landed after a bit of work, and seems to work
-        // pretty well in practrice.
-        let availableInputs = callUIAdapter.audioService.availableInputs
-        self.allAudioSources.formUnion(availableInputs)
-    }
-
     func presentAudioSourcePicker() {
         AssertIsOnMainThread()
 
@@ -724,7 +708,7 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
             return
         }
 
-        // Marquee scrolling is distractingn during a video call, disable it.
+        // Marquee scrolling is distracting during a video call, disable it.
         contactNameLabel.labelize = call.hasLocalVideo
 
         audioModeMuteButton.isSelected = call.isMuted
@@ -779,8 +763,6 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
             audioSourceButton.isHidden = false
         } else {
             // No bluetooth audio detected
-
-            audioSourceButton.isSelected = call.isSpeakerphoneEnabled
             audioSourceButton.setImage(#imageLiteral(resourceName: "audio-call-speaker-inactive"), for: .normal)
             audioSourceButton.setImage(#imageLiteral(resourceName: "audio-call-speaker-active"), for: .selected)
 
@@ -820,6 +802,29 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
         updateCallStatusLabel(callState: call.state)
     }
 
+    // We update the audioSourceButton outside of the main `updateCallUI`
+    // because `updateCallUI` is intended to be idempotent, which isn't possible
+    // with external speaker state because:
+    // - the system API which enables the external speaker is a (somewhat slow) asyncronous
+    //   operation
+    // - we want to give immediate UI feedback by marking the pressed button as selected
+    //   before the operation completes.
+    func updateAudioSourceButtonIsSelected() {
+        guard callUIAdapter.audioService.isSpeakerphoneEnabled else {
+            self.audioSourceButton.isSelected = false
+            return
+        }
+
+        // VideoChat mode enables the output speaker, but we don't
+        // want to highlight the speaker button in that case.
+        guard !call.hasLocalVideo else {
+            self.audioSourceButton.isSelected = false
+            return
+        }
+
+        self.audioSourceButton.isSelected = true
+    }
+
     // MARK: - Actions
 
     /**
@@ -852,13 +857,9 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
 
     func didPressSpeakerphone(sender button: UIButton) {
         Logger.info("\(TAG) called \(#function)")
+
         button.isSelected = !button.isSelected
-        if button.isSelected {
+        callUIAdapter.audioService.requestSpeakerphone(isEnabled: button.isSelected)
-            callUIAdapter.setAudioSource(call: call, audioSource: AudioSource.builtInSpeaker)
-        } else {
-            // use default audio source
-            callUIAdapter.setAudioSource(call: call, audioSource: nil)
-        }
     }
 
     func didPressTextMessage(sender button: UIButton) {
@@ -961,6 +962,29 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
         self.updateCallUI(callState: call.state)
     }
 
+    // MARK: CallAudioServiceDelegate
+
+    func callAudioService(_ callAudioService: CallAudioService, didUpdateIsSpeakerphoneEnabled isSpeakerphoneEnabled: Bool) {
+        AssertIsOnMainThread()
+
+        updateAudioSourceButtonIsSelected()
+    }
+
+    func callAudioServiceDidChangeAudioSession(_ callAudioService: CallAudioService) {
+        AssertIsOnMainThread()
+
+        // Which sources are available depends on the state of your Session.
+        // When the audio session is not yet in PlayAndRecord none are available
+        // Then if we're in speakerphone, bluetooth isn't available.
+        // So we accrue all possible audio sources in a set, and that list lives as longs as the CallViewController
+        // The downside of this is that if you e.g. unpair your bluetooth mid call, it will still appear as an option
+        // until your next call.
+        // FIXME: There's got to be a better way, but this is where I landed after a bit of work, and seems to work
+        // pretty well in practice.
+        let availableInputs = callAudioService.availableInputs
+        self.allAudioSources.formUnion(availableInputs)
+    }
+
     // MARK: - Video
 
     internal func updateLocalVideoTrack(localVideoTrack: RTCVideoTrack?) {
@@ -979,6 +1003,7 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
         localVideoView.isHidden = isHidden
 
         updateLocalVideoLayout()
+        updateAudioSourceButtonIsSelected()
     }
 
     var hasRemoteVideoTrack: Bool {
@@ -1002,6 +1027,8 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver {
     }
 
     internal func dismissIfPossible(shouldDelay: Bool, ignoreNag: Bool = false, completion: (() -> Swift.Void)? = nil) {
+        callUIAdapter.audioService.delegate = nil
+
         if hasDismissed {
             // Don't dismiss twice.
             return

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -3174,17 +3174,14 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     NSURL *fileURL = [NSURL fileURLWithPath:filepath];
 
     // Setup audio session
-    AVAudioSession *session = [AVAudioSession sharedInstance];
+    BOOL configuredAudio = [OWSAudioSession.shared setRecordCategory];
-    OWSAssert(session.recordPermission == AVAudioSessionRecordPermissionGranted);
+    if (!configuredAudio) {
-
+        OWSFail(@"%@ Couldn't configure audio session", self.logTag);
-    NSError *error;
-    [session setCategory:AVAudioSessionCategoryRecord error:&error];
-    if (error) {
-        OWSFail(@"%@ Couldn't configure audio session: %@", self.logTag, error);
         [self cancelVoiceMemo];
         return;
     }
 
+    NSError *error;
     // Initiate and prepare the recorder
     self.audioRecorder = [[AVAudioRecorder alloc] initWithURL:fileURL
                                                      settings:@{
@@ -3232,7 +3229,7 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
 
     NSTimeInterval durationSeconds = self.audioRecorder.currentTime;
 
-    [self.audioRecorder stop];
+    [self stopRecording];
 
     const NSTimeInterval kMinimumRecordingTimeSeconds = 1.f;
     if (durationSeconds < kMinimumRecordingTimeSeconds) {
@@ -3279,20 +3276,18 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     }
 }
 
+- (void)stopRecording
+{
+    [self.audioRecorder stop];
+    [OWSAudioSession.shared endAudioActivity];
+}
+
 - (void)cancelRecordingVoiceMemo
 {
     OWSAssertIsOnMainThread();
-
     DDLogDebug(@"cancelRecordingVoiceMemo");
 
-    [self resetRecordingVoiceMemo];
+    [self stopRecording];
-}
-
-- (void)resetRecordingVoiceMemo
-{
-    OWSAssertIsOnMainThread();
-
-    [self.audioRecorder stop];
     self.audioRecorder = nil;
     self.voiceMessageUUID = nil;
 }

Signal/src/ViewControllers/MediaDetailViewController.m

@@ -16,6 +16,7 @@
 #import <AVKit/AVKit.h>
 #import <MediaPlayer/MPMoviePlayerViewController.h>
 #import <MediaPlayer/MediaPlayer.h>
+#import <SignalMessaging/SignalMessaging-Swift.h>
 #import <SignalServiceKit/NSData+Image.h>
 #import <YYImage/YYImage.h>
 
@@ -46,7 +47,10 @@ NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark -
 
-@interface MediaDetailViewController () <UIScrollViewDelegate, UIGestureRecognizerDelegate, PlayerProgressBarDelegate>
+@interface MediaDetailViewController () <UIScrollViewDelegate,
+    UIGestureRecognizerDelegate,
+    PlayerProgressBarDelegate,
+    OWSVideoPlayerDelegate>
 
 @property (nonatomic) UIScrollView *scrollView;
 @property (nonatomic) UIView *mediaView;
@@ -64,7 +68,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic) UIToolbar *footerBar;
 @property (nonatomic) BOOL areToolbarsHidden;
 
-@property (nonatomic, nullable) AVPlayer *videoPlayer;
+@property (nonatomic, nullable) OWSVideoPlayer *videoPlayer;
 @property (nonatomic, nullable) UIButton *playVideoButton;
 @property (nonatomic, nullable) PlayerProgressBar *videoProgressBar;
 @property (nonatomic, nullable) UIBarButtonItem *videoPlayBarButton;
@@ -306,7 +310,7 @@ NS_ASSUME_NONNULL_BEGIN
         if (@available(iOS 9, *)) {
             PlayerProgressBar *videoProgressBar = [PlayerProgressBar new];
             videoProgressBar.delegate = self;
-            videoProgressBar.player = self.videoPlayer;
+            videoProgressBar.player = self.videoPlayer.avPlayer;
 
             self.videoProgressBar = videoProgressBar;
             [self.view addSubview:videoProgressBar];
@@ -435,17 +439,13 @@ NS_ASSUME_NONNULL_BEGIN
     }
 
     if (@available(iOS 9.0, *)) {
-        AVPlayer *player = [[AVPlayer alloc] initWithURL:self.attachmentUrl];
+        OWSVideoPlayer *player = [[OWSVideoPlayer alloc] initWithUrl:self.attachmentUrl];
         [player seekToTime:kCMTimeZero];
+        player.delegate = self;
         self.videoPlayer = player;
 
-        [[NSNotificationCenter defaultCenter] addObserver:self
-                                                 selector:@selector(playerItemDidPlayToCompletion:)
-                                                     name:AVPlayerItemDidPlayToEndTimeNotification
-                                                   object:player.currentItem];
-
         VideoPlayerView *playerView = [VideoPlayerView new];
-        playerView.player = player;
+        playerView.player = player.avPlayer;
 
         [NSLayoutConstraint autoSetPriority:UILayoutPriorityDefaultLow
                              forConstraints:^{
@@ -892,20 +892,12 @@ NS_ASSUME_NONNULL_BEGIN
 {
     if (@available(iOS 9, *)) {
         OWSAssert(self.videoPlayer);
-        AVPlayer *player = self.videoPlayer;
 
         [self updateFooterBarButtonItemsWithIsPlayingVideo:YES];
         self.playVideoButton.hidden = YES;
         self.areToolbarsHidden = YES;
 
-        OWSAssert(player.currentItem);
+        [self.videoPlayer play];
-        AVPlayerItem *item = player.currentItem;
-        if (CMTIME_COMPARE_INLINE(item.currentTime, ==, item.duration)) {
-            // Rewind for repeated plays
-            [player seekToTime:kCMTimeZero];
-        }
-
-        [player play];
     } else {
         [self legacyPlayVideo];
         return;
@@ -921,7 +913,9 @@ NS_ASSUME_NONNULL_BEGIN
     [self.videoPlayer pause];
 }
 
-- (void)playerItemDidPlayToCompletion:(NSNotification *)notification
+#pragma mark - OWSVideoPlayer
+
+- (void)videoPlayerDidPlayToCompletion:(OWSVideoPlayer *)videoPlayer
 {
     OWSAssert(self.isVideo);
     OWSAssert(self.videoPlayer);
@@ -933,6 +927,8 @@ NS_ASSUME_NONNULL_BEGIN
     [self updateFooterBarButtonItemsWithIsPlayingVideo:NO];
 }
 
+#pragma mark - PlayerProgressBarDelegate
+
 - (void)playerProgressBarDidStartScrubbing:(PlayerProgressBar *)playerProgressBar
 {
     OWSAssert(self.videoPlayer);

Signal/src/ViewControllers/MessageDetailViewController.swift

@@ -88,8 +88,6 @@ class MessageDetailViewController: OWSViewController, UIScrollViewDelegate, Medi
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
 
-        mediaMessageView?.viewWillAppear(animated)
-
         updateTextLayout()
 
         if mode == .focusOnMetadata {
@@ -118,12 +116,6 @@ class MessageDetailViewController: OWSViewController, UIScrollViewDelegate, Medi
         }
     }
 
-    override func viewWillDisappear(_ animated: Bool) {
-        super.viewWillDisappear(animated)
-
-        mediaMessageView?.viewWillDisappear(animated)
-    }
-
     // MARK: - Create Views
 
     private func createViews() {

Signal/src/call/CallAudioService.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -7,8 +7,6 @@ import AVFoundation
 import SignalServiceKit
 import SignalMessaging
 
-public let CallAudioServiceSessionChanged = Notification.Name("CallAudioServiceSessionChanged")
-
 struct AudioSource: Hashable {
 
     let image: UIImage
@@ -88,11 +86,21 @@ struct AudioSource: Hashable {
     }
 }
 
+protocol CallAudioServiceDelegate: class {
+    func callAudioService(_ callAudioService: CallAudioService, didUpdateIsSpeakerphoneEnabled isEnabled: Bool)
+    func callAudioServiceDidChangeAudioSession(_ callAudioService: CallAudioService)
+}
+
 @objc class CallAudioService: NSObject, CallObserver {
 
     private var vibrateTimer: Timer?
     private let audioPlayer = AVAudioPlayer()
     private let handleRinging: Bool
+    weak var delegate: CallAudioServiceDelegate? {
+        willSet {
+            assert(newValue == nil || delegate == nil)
+        }
+    }
 
     class Sound: NSObject {
 
@@ -137,8 +145,11 @@ struct AudioSource: Hashable {
     // `pulseDuration` is the small pause between the two vibrations in the pair.
     private let pulseDuration = 0.2
 
-    var audioSession: CallAudioSession {
+    var audioSession: OWSAudioSession {
-        return CallAudioSession.shared
+        return OWSAudioSession.shared
+    }
+    var avAudioSession: AVAudioSession {
+        return AVAudioSession.sharedInstance()
     }
 
     // MARK: - Initializers
@@ -151,7 +162,12 @@ struct AudioSource: Hashable {
         SwiftSingletons.register(self)
 
         // Configure audio session so we don't prompt user with Record permission until call is connected.
-        audioSession.configure()
+
+        audioSession.configureRTCAudio()
+        NotificationCenter.default.addObserver(forName: .AVAudioSessionRouteChange, object: avAudioSession, queue: nil) { _ in
+            assert(!Thread.isMainThread)
+            self.updateIsSpeakerphoneEnabled()
+        }
     }
 
     // MARK: - CallObserver
@@ -177,6 +193,12 @@ struct AudioSource: Hashable {
         AssertIsOnMainThread()
 
         ensureProperAudioSession(call: call)
+
+        if let audioSource = audioSource, audioSource.isBuiltInSpeaker {
+            self.isSpeakerphoneEnabled = true
+        } else {
+            self.isSpeakerphoneEnabled = false
+        }
     }
 
     internal func hasLocalVideoDidChange(call: SignalCall, hasLocalVideo: Bool) {
@@ -185,11 +207,43 @@ struct AudioSource: Hashable {
         ensureProperAudioSession(call: call)
     }
 
+    // Speakerphone can be manipulated by the in-app callscreen or via the system callscreen (CallKit).
+    // Unlike other CallKit CallScreen buttons, enabling doesn't trigger a CXAction, so it's not as simple
+    // to track state changes. Instead we never store the state and directly access the ground-truth in the
+    // AVAudioSession.
+    private(set) var isSpeakerphoneEnabled: Bool = false {
+        didSet {
+            self.delegate?.callAudioService(self, didUpdateIsSpeakerphoneEnabled: isSpeakerphoneEnabled)
+        }
+    }
+
+    public func requestSpeakerphone(isEnabled: Bool) {
+        // This is a little too slow to execute on the main thread and the results are not immediately available after execution
+        // anyway, so we dispatch async. If you need to know the new value, you'll need to check isSpeakerphoneEnabled and take
+        // advantage of the CallAudioServiceDelegate.callAudioService(_:didUpdateIsSpeakerphoneEnabled:)
+        DispatchQueue.global().async {
+            do {
+                try self.avAudioSession.overrideOutputAudioPort( isEnabled ? .speaker : .none )
+            } catch {
+                owsFail("\(self.logTag) failed to set \(#function) = \(isEnabled) with error: \(error)")
+            }
+        }
+    }
+
+    private func updateIsSpeakerphoneEnabled() {
+        let value = avAudioSession.currentRoute.outputs.contains { (portDescription: AVAudioSessionPortDescription) -> Bool in
+            return portDescription.portName == AVAudioSessionPortBuiltInSpeaker
+        }
+        DispatchQueue.main.async {
+            self.isSpeakerphoneEnabled = value
+        }
+    }
+
     private func ensureProperAudioSession(call: SignalCall?) {
         AssertIsOnMainThread()
 
         guard let call = call else {
-            setAudioSession(category: AVAudioSessionCategoryPlayback,
+            setAudioSession(category: AVAudioSessionCategorySoloAmbient,
                             mode: AVAudioSessionModeDefault)
             return
         }
@@ -206,7 +260,7 @@ struct AudioSource: Hashable {
             // SoloAmbient plays through speaker, but respects silent switch
             setAudioSession(category: AVAudioSessionCategorySoloAmbient,
                             mode: AVAudioSessionModeDefault)
-        } else if call.state == .connected, call.hasLocalVideo {
+        } else if call.hasLocalVideo {
             // Because ModeVideoChat affects gain, we don't want to apply it until the call is connected.
             // otherwise sounds like ringing will be extra loud for video vs. speakerphone
 
@@ -227,26 +281,15 @@ struct AudioSource: Hashable {
                             options: options)
         }
 
-        let session = AVAudioSession.sharedInstance()
         do {
             // It's important to set preferred input *after* ensuring properAudioSession
             // because some sources are only valid for certain category/option combinations.
-            let existingPreferredInput = session.preferredInput
+            let existingPreferredInput = avAudioSession.preferredInput
             if  existingPreferredInput != call.audioSource?.portDescription {
                 Logger.info("\(self.logTag) changing preferred input: \(String(describing: existingPreferredInput)) -> \(String(describing: call.audioSource?.portDescription))")
-                try session.setPreferredInput(call.audioSource?.portDescription)
+                try avAudioSession.setPreferredInput(call.audioSource?.portDescription)
             }
 
-            if call.isSpeakerphoneEnabled || (call.hasLocalVideo && call.state != .connected) {
-                // We want consistent ringer-volume between speaker-phone and video chat.
-                // But because using VideoChat mode has noticeably higher output gain, we treat
-                // video chat like speakerphone mode until the call is connected.
-                Logger.verbose("\(self.logTag) enabling speakerphone overrideOutputAudioPort(.speaker)")
-                try session.overrideOutputAudioPort(.speaker)
-            } else {
-                Logger.verbose("\(self.logTag) disabling spearkerphone overrideOutputAudioPort(.none) ")
-                try session.overrideOutputAudioPort(.none)
-            }
         } catch {
             owsFail("\(self.logTag) failed setting audio source with error: \(error) isSpeakerPhoneEnabled: \(call.isSpeakerphoneEnabled)")
         }
@@ -328,6 +371,7 @@ struct AudioSource: Hashable {
         AssertIsOnMainThread()
 
         play(sound: Sound.failure)
+        handleCallEnded(call: call)
     }
 
     private func handleLocalHangup(call: SignalCall) {
@@ -363,7 +407,8 @@ struct AudioSource: Hashable {
         AssertIsOnMainThread()
 
         // Stop solo audio, revert to default.
-        setAudioSession(category: AVAudioSessionCategoryAmbient)
+        isSpeakerphoneEnabled = false
+        setAudioSession(category: AVAudioSessionCategorySoloAmbient)
     }
 
     // MARK: Playing Sounds
@@ -439,9 +484,7 @@ struct AudioSource: Hashable {
     // Specifically if you call it while speakerphone is enabled you won't see 
     // any connected bluetooth routes.
     var availableInputs: [AudioSource] {
-        let session = AVAudioSession.sharedInstance()
+        guard let availableInputs = avAudioSession.availableInputs else {
-
-        guard let availableInputs = session.availableInputs else {
             // I'm not sure why this would happen, but it may indicate an error.
             // In practice, I haven't seen it on iOS9+.
             //
@@ -468,8 +511,7 @@ struct AudioSource: Hashable {
         // system state to determine the current audio source.
         // If a bluetooth is connected, this will be bluetooth, otherwise
         // this will be the receiver.
-        let session = AVAudioSession.sharedInstance()
+        guard let portDescription = avAudioSession.currentRoute.inputs.first else {
-        guard let portDescription = session.currentRoute.inputs.first else {
             return nil
         }
 
@@ -482,13 +524,12 @@ struct AudioSource: Hashable {
 
         AssertIsOnMainThread()
 
-        let session = AVAudioSession.sharedInstance()
         var audioSessionChanged = false
         do {
             if #available(iOS 10.0, *), let mode = mode {
-                let oldCategory = session.category
+                let oldCategory = avAudioSession.category
-                let oldMode = session.mode
+                let oldMode = avAudioSession.mode
-                let oldOptions = session.categoryOptions
+                let oldOptions = avAudioSession.categoryOptions
 
                 guard oldCategory != category || oldMode != mode || oldOptions != options else {
                     return
@@ -505,13 +546,13 @@ struct AudioSource: Hashable {
                 if oldOptions != options {
                     Logger.debug("\(self.logTag) audio session changed options: \(oldOptions) -> \(options) ")
                 }
-                try session.setCategory(category, mode: mode, options: options)
+                try avAudioSession.setCategory(category, mode: mode, options: options)
 
             } else {
-                let oldCategory = session.category
+                let oldCategory = avAudioSession.category
-                let oldOptions = session.categoryOptions
+                let oldOptions = avAudioSession.categoryOptions
 
-                guard session.category != category || session.categoryOptions != options else {
+                guard avAudioSession.category != category || avAudioSession.categoryOptions != options else {
                     return
                 }
 
@@ -523,7 +564,7 @@ struct AudioSource: Hashable {
                 if oldOptions != options {
                     Logger.debug("\(self.logTag) audio session changed options: \(oldOptions) -> \(options) ")
                 }
-                try session.setCategory(category, with: options)
+                try avAudioSession.setCategory(category, with: options)
 
             }
         } catch {
@@ -533,8 +574,7 @@ struct AudioSource: Hashable {
 
         if audioSessionChanged {
             Logger.info("\(self.logTag) in \(#function)")
-            // Update call view synchronously; already on main thread.
+            self.delegate?.callAudioServiceDidChangeAudioSession(self)
-            NotificationCenter.default.post(name:CallAudioServiceSessionChanged, object: nil)
         }
     }
 }

Signal/src/call/CallAudioSession.swift

@@ -1,51 +0,0 @@
-//
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
-//
-
-import Foundation
-import WebRTC
-
-/**
- * By default WebRTC starts the audio session (PlayAndRecord) immediately upon creating the peer connection
- * but we want to create the peer connection and set up all the signaling channels before we prompt the user
- * for an incoming call. Without manually handling the session, this would result in the user seeing a recording
- * permission requested (and recording banner) before they even know they have an incoming call.
- *
- * By using the `useManualAudio` and `isAudioEnabled` attributes of the RTCAudioSession we can delay recording until
- * it makes sense.
- */
-class CallAudioSession {
-
-    let TAG = "[CallAudioSession]"
-
-    // Force singleton access
-    static let shared = CallAudioSession()
-    private init() {}
-
-    /**
-     * The private class that manages AVAudioSession for WebRTC
-     */
-    private let rtcAudioSession = RTCAudioSession.sharedInstance()
-
-    /**
-    * This must be called before any audio tracks are added to the peerConnection, else we'll start recording before all
-    * our signaling is set up.
-    */
-    func configure() {
-        Logger.info("\(TAG) in \(#function)")
-        rtcAudioSession.useManualAudio = true
-    }
-
-    /**
-     * Because we useManualAudio with our RTCAudioSession, we have to start/stop the recording audio session ourselves.
-     * See header for details on  manual audio.
-     */
-    var isRTCAudioEnabled: Bool {
-        get {
-            return rtcAudioSession.isAudioEnabled
-        }
-        set {
-            rtcAudioSession.isAudioEnabled = newValue
-        }
-    }
-}

Signal/src/call/CallService.swift

@@ -1024,6 +1024,9 @@ protocol CallServiceObserver: class {
         //        this.messageSender.cancelInFlightRequests();
 
         if let peerConnectionClient = self.peerConnectionClient {
+            // Stop audio capture ASAP
+            ensureAudioState(call: call, peerConnectionClient: peerConnectionClient)
+
             // If the call is connected, we can send the hangup via the data channel for faster hangup.
             let message = DataChannelMessage.forHangup(callId: call.signalingId)
             peerConnectionClient.sendDataChannelMessage(data: message.asData(), description: "hangup", isCritical: true)

Signal/src/call/NonCallKitCallUIAdaptee.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -89,7 +89,7 @@ class NonCallKitCallUIAdaptee: NSObject, CallUIAdaptee {
             return
         }
 
-        CallAudioSession.shared.isRTCAudioEnabled = true
+        OWSAudioSession.shared.isRTCAudioEnabled = true
         self.callService.handleAnswerCall(call)
     }
 
@@ -123,7 +123,7 @@ class NonCallKitCallUIAdaptee: NSObject, CallUIAdaptee {
     func recipientAcceptedCall(_ call: SignalCall) {
         AssertIsOnMainThread()
 
-        CallAudioSession.shared.isRTCAudioEnabled = true
+        OWSAudioSession.shared.isRTCAudioEnabled = true
     }
 
     func localHangupCall(_ call: SignalCall) {

Signal/src/call/Speakerbox/CallKitCallUIAdaptee.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -345,14 +345,14 @@ final class CallKitCallUIAdaptee: NSObject, CallUIAdaptee, CXProviderDelegate {
 
         Logger.debug("\(TAG) Received \(#function)")
 
-        CallAudioSession.shared.isRTCAudioEnabled = true
+        OWSAudioSession.shared.isRTCAudioEnabled = true
     }
 
     func provider(_ provider: CXProvider, didDeactivate audioSession: AVAudioSession) {
         AssertIsOnMainThread()
 
         Logger.debug("\(TAG) Received \(#function)")
-        CallAudioSession.shared.isRTCAudioEnabled = false
+        OWSAudioSession.shared.isRTCAudioEnabled = false
     }
 
     // MARK: - Util

SignalMessaging/attachments/AttachmentApprovalViewController.swift

@@ -13,7 +13,7 @@ public protocol AttachmentApprovalViewControllerDelegate: class {
 }
 
 @objc
-public class AttachmentApprovalViewController: OWSViewController, CaptioningToolbarDelegate, PlayerProgressBarDelegate {
+public class AttachmentApprovalViewController: OWSViewController, CaptioningToolbarDelegate, PlayerProgressBarDelegate, OWSVideoPlayerDelegate {
 
     let TAG = "[AttachmentApprovalViewController]"
     weak var delegate: AttachmentApprovalViewControllerDelegate?
@@ -27,7 +27,7 @@ public class AttachmentApprovalViewController: OWSViewController, CaptioningTool
     // MARK: Properties
 
     let attachment: SignalAttachment
-    private var videoPlayer: AVPlayer?
+    private var videoPlayer: OWSVideoPlayer?
 
     private(set) var bottomToolbar: UIView!
     private(set) var mediaMessageView: MediaMessageView!
@@ -79,8 +79,6 @@ public class AttachmentApprovalViewController: OWSViewController, CaptioningTool
         super.viewWillAppear(animated)
 
         CurrentAppContext().setStatusBarHidden(true, animated: animated)
-
-        mediaMessageView.viewWillAppear(animated)
     }
 
     override public func viewDidAppear(_ animated: Bool) {
@@ -92,8 +90,6 @@ public class AttachmentApprovalViewController: OWSViewController, CaptioningTool
         Logger.debug("\(logTag) in \(#function)")
         super.viewWillDisappear(animated)
 
-        mediaMessageView.viewWillDisappear(animated)
-
         // Since this VC is being dismissed, the "show status bar" animation would feel like
         // it's occuring on the presenting view controller - it's better not to animate at all.
         CurrentAppContext().setStatusBarHidden(false, animated: false)
@@ -182,16 +178,12 @@ public class AttachmentApprovalViewController: OWSViewController, CaptioningTool
                     return
                 }
 
-                let player = AVPlayer(url: videoURL)
+                let player = OWSVideoPlayer(url: videoURL)
                 self.videoPlayer = player
-
+                player.delegate = self
-                NotificationCenter.default.addObserver(self,
-                                                       selector: #selector(playerItemDidPlayToCompletion(_:)),
-                                                       name: NSNotification.Name.AVPlayerItemDidPlayToEndTime,
-                                                       object: player.currentItem)
 
                 let playerView = VideoPlayerView()
-                playerView.player = player
+                playerView.player = player.avPlayer
                 self.mediaMessageView.addSubview(playerView)
                 playerView.autoPinEdgesToSuperviewEdges()
 
@@ -199,7 +191,7 @@ public class AttachmentApprovalViewController: OWSViewController, CaptioningTool
                 playerView.addGestureRecognizer(pauseGesture)
 
                 let progressBar = PlayerProgressBar()
-                progressBar.player = player
+                progressBar.player = player.avPlayer
                 progressBar.delegate = self
 
                 // we don't want the progress bar to zoom during "pinch-to-zoom"
@@ -300,17 +292,6 @@ public class AttachmentApprovalViewController: OWSViewController, CaptioningTool
             UIView.animate(withDuration: 0.1) {
                 playVideoButton.alpha = 0.0
             }
-
-            guard let item = videoPlayer.currentItem else {
-                owsFail("\(TAG) video player item was unexpectedly nil")
-                return
-            }
-
-            if item.currentTime() == item.duration {
-                // Rewind for repeated plays, but only if it previously played to end.
-                videoPlayer.seek(to: kCMTimeZero)
-            }
-
             videoPlayer.play()
         } else {
             self.playLegacyVideo()
@@ -353,11 +334,12 @@ public class AttachmentApprovalViewController: OWSViewController, CaptioningTool
     }
 
     @objc
-    private func playerItemDidPlayToCompletion(_ notification: Notification) {
+    public func videoPlayerDidPlayToCompletion(_ videoPlayer: OWSVideoPlayer) {
         guard let playVideoButton = self.playVideoButton else {
             owsFail("\(TAG) playVideoButton was unexpectedly nil")
             return
         }
+
         UIView.animate(withDuration: 0.1) {
             playVideoButton.alpha = 1.0
         }

SignalMessaging/attachments/MediaMessageView.swift

@@ -87,18 +87,6 @@ public class MediaMessageView: UIView, OWSAudioAttachmentPlayerDelegate {
         NotificationCenter.default.removeObserver(self)
     }
 
-    // MARK: View Lifecycle
-
-    @objc
-    public func viewWillAppear(_ animated: Bool) {
-        OWSAudioAttachmentPlayer.setAudioIgnoresHardwareMuteSwitch(true)
-    }
-
-    @objc
-    public func viewWillDisappear(_ animated: Bool) {
-        OWSAudioAttachmentPlayer.setAudioIgnoresHardwareMuteSwitch(false)
-    }
-
     // MARK: - Create Views
 
     private func createViews() {

SignalMessaging/attachments/OWSAudioAttachmentPlayer.h

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 NS_ASSUME_NONNULL_BEGIN
@@ -25,8 +25,6 @@ typedef NS_ENUM(NSInteger, AudioPlaybackState) {
 
 @interface OWSAudioAttachmentPlayer : NSObject
 
-+ (void)setAudioIgnoresHardwareMuteSwitch:(BOOL)shouldIgnore;
-
 @property (nonatomic, readonly, weak) id<OWSAudioAttachmentPlayerDelegate> delegate;
 
 // This property can be used to associate instances of the player with view

SignalMessaging/attachments/OWSAudioAttachmentPlayer.m

@@ -22,17 +22,6 @@ NS_ASSUME_NONNULL_BEGIN
 
 @implementation OWSAudioAttachmentPlayer
 
-+ (void)setAudioIgnoresHardwareMuteSwitch:(BOOL)shouldIgnore
-{
-    NSError *error = nil;
-    BOOL success = [[AVAudioSession sharedInstance]
-        setCategory:(shouldIgnore ? AVAudioSessionCategoryPlayback : AVAudioSessionCategoryPlayAndRecord)error:&error];
-    OWSAssert(!error);
-    if (!success || error) {
-        DDLogError(@"%@ Error in setAudioIgnoresHardwareMuteSwitch: %d", self.logTag, shouldIgnore);
-    }
-}
-
 - (instancetype)initWithMediaUrl:(NSURL *)mediaUrl delegate:(id<OWSAudioAttachmentPlayerDelegate>)delegate
 {
     self = [super init];
@@ -76,7 +65,7 @@ NS_ASSUME_NONNULL_BEGIN
     OWSAssert(self.mediaUrl);
     OWSAssert([self.delegate audioPlaybackState] != AudioPlaybackState_Playing);
 
-    [[self class] setAudioIgnoresHardwareMuteSwitch:YES];
+    [OWSAudioSession.shared setPlaybackCategory];
 
     [self.audioPlayerPoller invalidate];
 
@@ -101,7 +90,6 @@ NS_ASSUME_NONNULL_BEGIN
         self.audioPlayer.delegate = self;
     }
 
-    [self.audioPlayer prepareToPlay];
     [self.audioPlayer play];
     [self.audioPlayerPoller invalidate];
     self.audioPlayerPoller = [NSTimer weakScheduledTimerWithTimeInterval:.05f
@@ -123,6 +111,7 @@ NS_ASSUME_NONNULL_BEGIN
     [self.audioPlayerPoller invalidate];
     [self.delegate setAudioProgress:[self.audioPlayer currentTime] duration:[self.audioPlayer duration]];
 
+    [OWSAudioSession.shared endAudioActivity];
     [DeviceSleepManager.sharedInstance removeBlockWithBlockObject:self];
 }
 
@@ -135,6 +124,7 @@ NS_ASSUME_NONNULL_BEGIN
     [self.audioPlayerPoller invalidate];
     [self.delegate setAudioProgress:0 duration:0];
 
+    [OWSAudioSession.shared endAudioActivity];
     [DeviceSleepManager.sharedInstance removeBlockWithBlockObject:self];
 }
 

SignalMessaging/attachments/OWSVideoPlayer.swift

@@ -0,0 +1,72 @@
+//
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//
+
+import Foundation
+import AVFoundation
+
+@objc
+protocol OWSVideoPlayerDelegate: class {
+    @available(iOSApplicationExtension 9.0, *)
+    func videoPlayerDidPlayToCompletion(_ videoPlayer: OWSVideoPlayer)
+}
+
+@objc
+public class OWSVideoPlayer: NSObject {
+
+    let avPlayer: AVPlayer
+
+    weak var delegate: OWSVideoPlayerDelegate?
+
+    @available(iOS 9.0, *)
+    init(url: URL) {
+        self.avPlayer = AVPlayer(url: url)
+
+        super.init()
+
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(playerItemDidPlayToCompletion(_:)),
+                                               name: NSNotification.Name.AVPlayerItemDidPlayToEndTime,
+                                               object: avPlayer.currentItem)
+    }
+
+    // MARK: Playback Controls
+
+    @available(iOS 9.0, *)
+    public func pause() {
+        avPlayer.pause()
+        OWSAudioSession.shared.endAudioActivity()
+    }
+
+    @available(iOS 9.0, *)
+    public func play() {
+        OWSAudioSession.shared.setPlaybackCategory()
+
+        guard let item = avPlayer.currentItem else {
+            owsFail("\(logTag) video player item was unexpectedly nil")
+            return
+        }
+
+        if item.currentTime() == item.duration {
+            // Rewind for repeated plays, but only if it previously played to end.
+            avPlayer.seek(to: kCMTimeZero)
+        }
+
+        avPlayer.play()
+    }
+
+    @available(iOS 9.0, *)
+    @objc(seekToTime:)
+    public func seek(to time: CMTime) {
+        avPlayer.seek(to: time)
+    }
+
+    // MARK: private
+
+    @objc
+    @available(iOS 9.0, *)
+    private func playerItemDidPlayToCompletion(_ notification: Notification) {
+        self.delegate?.videoPlayerDidPlayToCompletion(self)
+        OWSAudioSession.shared.endAudioActivity()
+    }
+}

SignalMessaging/contacts/ViewControllerUtils.h

@@ -18,8 +18,6 @@ NS_ASSUME_NONNULL_BEGIN
                 replacementString:(NSString *)insertionText
                       countryCode:(NSString *)countryCode;
 
-+ (void)setAudioIgnoresHardwareMuteSwitch:(BOOL)shouldIgnore;
-
 + (NSString *)examplePhoneNumberForCountryCode:(NSString *)countryCode callingCode:(NSString *)callingCode;
 
 @end

SignalMessaging/contacts/ViewControllerUtils.m

@@ -74,17 +74,6 @@ NS_ASSUME_NONNULL_BEGIN
     [textField setSelectedTextRange:[textField textRangeFromPosition:pos toPosition:pos]];
 }
 
-+ (void)setAudioIgnoresHardwareMuteSwitch:(BOOL)shouldIgnore
-{
-    NSError *error = nil;
-    BOOL success = [[AVAudioSession sharedInstance]
-        setCategory:(shouldIgnore ? AVAudioSessionCategoryPlayback : AVAudioSessionCategoryPlayAndRecord)error:&error];
-    OWSAssert(!error);
-    if (!success || error) {
-        DDLogError(@"%@ Error in setAudioIgnoresHardwareMuteSwitch: %d", self.logTag, shouldIgnore);
-    }
-}
-
 + (NSString *)examplePhoneNumberForCountryCode:(NSString *)countryCode callingCode:(NSString *)callingCode
 {
     OWSAssert(countryCode.length > 0);

SignalMessaging/environment/OWSAudioSession.swift

@@ -0,0 +1,101 @@
+//
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//
+
+import Foundation
+import WebRTC
+
+@objc
+public class OWSAudioSession: NSObject {
+
+    // Force singleton access
+    public static let shared = OWSAudioSession()
+    private override init() {}
+    private let avAudioSession = AVAudioSession.sharedInstance()
+
+    // Ignores hardware mute switch, plays through external speaker
+    public func setPlaybackCategory() {
+        Logger.debug("\(logTag) in \(#function)")
+
+        // In general, we should have put the audio session back to it's default
+        // category when we were done with whatever activity required it to be modified
+        assert(avAudioSession.category == AVAudioSessionCategorySoloAmbient)
+
+        do {
+            try avAudioSession.setCategory(AVAudioSessionCategoryPlayback)
+        } catch {
+            owsFail("\(logTag) in \(#function) failed with error: \(error)")
+        }
+    }
+
+    public func setRecordCategory() -> Bool {
+        Logger.debug("\(logTag) in \(#function)")
+
+        // In general, we should have put the audio session back to it's default
+        // category when we were done with whatever activity required it to be modified
+        assert(avAudioSession.category == AVAudioSessionCategorySoloAmbient)
+
+        assert(avAudioSession.recordPermission() == .granted)
+
+        do {
+            try avAudioSession.setCategory(AVAudioSessionCategoryRecord)
+            return true
+        } catch {
+            owsFail("\(logTag) in \(#function) failed with error: \(error)")
+            return false
+        }
+    }
+
+    public func endAudioActivity() {
+        Logger.debug("\(logTag) in \(#function)")
+
+        do {
+            try avAudioSession.setCategory(AVAudioSessionCategorySoloAmbient)
+
+            // When playing audio in Signal, other apps audio (e.g. Music) is paused.
+            // By notifying when we deactivate, the other app can resume playback.
+            try avAudioSession.setActive(false, with: [.notifyOthersOnDeactivation])
+        } catch {
+            owsFail("\(logTag) in \(#function) failed with error: \(error)")
+        }
+    }
+
+    // MARK: - WebRTC Audio
+
+    /**
+     * By default WebRTC starts the audio session (PlayAndRecord) immediately upon creating the peer connection
+     * but we want to create the peer connection and set up all the signaling channels before we prompt the user
+     * for an incoming call. Without manually handling the session, this would result in the user seeing a recording
+     * permission requested (and recording banner) before they even know they have an incoming call.
+     *
+     * By using the `useManualAudio` and `isAudioEnabled` attributes of the RTCAudioSession we can delay recording until
+     * it makes sense.
+     */
+
+    /**
+     * The private class that manages AVAudioSession for WebRTC
+     */
+    private let rtcAudioSession = RTCAudioSession.sharedInstance()
+
+    /**
+     * This must be called before any audio tracks are added to the peerConnection, else we'll start recording before all
+     * our signaling is set up.
+     */
+    public func configureRTCAudio() {
+        Logger.info("\(logTag) in \(#function)")
+        rtcAudioSession.useManualAudio = true
+    }
+
+    /**
+     * Because we useManualAudio with our RTCAudioSession, we have to start/stop the recording audio session ourselves.
+     * See header for details on  manual audio.
+     */
+    public var isRTCAudioEnabled: Bool {
+        get {
+            return rtcAudioSession.isAudioEnabled
+        }
+        set {
+            rtcAudioSession.isAudioEnabled = newValue
+        }
+    }
+}