Play a live stream with GoCoder SDK for iOS

Learn how to add a player view to a Wowza GoCoder™ SDK for iOS app and play a live stream, including an ultra low latency live stream from the Wowza Streaming Cloud™ service.

Notes:

• Creating ultra low latency stream targets requires a separate subscription to Wowza Streaming Cloud with Ultra Low Latency.
• Ultra low latency streams are subject to a default viewer limit of simultaneous viewers per stream according to the subscription plan you select. If this limit is exceeded, new stream viewers will receive an error and won't be able to establish a connection. If you have enabled and configured HLS as a backup for playback, ultra low latency stream viewers beyond the allotted limit can view the steam via the fallback HLS connection. See Wowza Streaming Cloud REST API limits for more information about limits.
• Playback over SSL isn't supported by GoCoder SDK at this time.

Contents

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Video tutorial: Build a playback app for iOS
Add a player view to an app
Configure the streaming server
Configure Apple HLS fallback
Set play options
Get the bitrate during playback
More resources

Video tutorial: Build a playback app for iOS

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This video shows how to build a playback app using the GoCoder SDK for iOS.

Add a player view to an app

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Use the WOWZPlayer and WOWZStatusCallback classes to add a player view to an app.

1. Create configuration and player properties.
    

   #pragma mark - GoCoder SDK Components
   @property (nonatomic, strong) WowzaConfig *goCoderConfig;
   @property (nonatomic, strong) WOWZPlayer *player;

2. Create a WOWZPlayer object and, if desired, register it for data events.
    

   // Register the GoCoder SDK license key
     NSString *SDKSampleAppLicenseKey = @"your-GoCoder-SDK-license-key";
     NSError *goCoderLicensingError = [WowzaGoCoder registerLicenseKey:SDKSampleAppLicenseKey];
     if (goCoderLicensingError != nil) {
       // Handle license key registration failure
     }
     else {
       self.player = [WOWZPlayer new];
       //Set default preroll buffer duration if you want a preroll buffer before a stream starts
        self.player.prerollDuration = 3; // 1-3 second buffer
       //Optionally set up data sink to handle in-stream events
       [self.player registerDataSink:self eventName:@"onTextData"];
     }
   

3. Implement the WOWZStatusCallback methods to respond and assign your player view.
    

   #pragma mark - WOWZStatusCallback Protocol Instance Methods
   
   - (void) onWOWZStatus:(WOWZStatus *) goCoderStatus {
     // A successful status transition has been reported by the GoCoder SDK
     
     switch (goCoderStatus.state) {
         
       case WOWZStateIdle:
               break;
         
       case WOWZStateStarting:
         // A streaming broadcast session is starting up
         self.player.playerView = self.view;
   
         break;
         
       case WOWZStateRunning:
         
         break;
         
       case WOWZStateStopping:
                break;
         
       case WOWZStateBuffering:
             break;
         
       default:
         break;
     }
   }

Configure the streaming server

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Specify the streaming server connection properties.

1. Write a configuration method that instantiates and assigns a configuration object to your property.
    

   -(void)setupConfig{
     WowzaConfig *config = [WowzaConfig new];
     config.hostAddress = @"your_server_ip";
     config.portNumber = 1935;
     config.streamName = @"a_stream_name";
     config.applicationName = @"your_application_name";
     config.audioEnabled = YES;
     config.videoEnabled = YES;
     
     //If authentication is required
     config.username = @"someusername";
     config.password = @"somepass";
     
     self.goCoderConfig = config;
   }

2. Call the configuration method.
    

   - (void)viewDidLoad {
     [super viewDidLoad];
     [self setupConfig];

3. Instruct the self.player object to play with the configuration method and register self as a delegate for callbacks.
    

   - (IBAction) didTapPlaybackButton:(id)sender {
     if ([self.player currentPlayState] == WOWZStateIdle) {
       [self.player play:self.goCoderConfig callback:self];
     }
     else {
       [self.player stop];
     }
   }

Configure Apple HLS fallback

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You can instruct the Wowza GoCoder SDK app to play an Apple HLS stream as a fallback if the primary stream fails to connect.

Note: If you're receiving an ultra low latency stream from the Wowza Streaming Cloud REST API, the target must be configured to enable HLS fallback. For instructions, see the Get started with ultra low latency streaming using the Wowza Streaming Cloud REST API. HLS fallback helps ensure successful playback but increases latency.

Use the following properties in WowzaConfig:

Property	Type	Description
allowHLSPlayback	Boolean	Specify true to enable Apple HLS fallback. When enabled, the player will switch to the Apple HLS URL after three failed attempts to play over the primary protocol.
hlsURL	string	The .m3u8 playlist URL. This is an NSString object.

The following example demonstrates how to verify that Apple HLS fallback is configured. It retrieves the allowHLSPlayback and hlsURL property values from your NSUserDefaults or from your configuration file.

- (void) viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    
    NSData *savedConfigData = [NSKeyedArchiver archivedDataWithRootObject:self.goCoderConfig];
    [[NSUserDefaults standardUserDefaults] setObject:savedConfigData forKey:SDKSampleSavedConfigKey];
    [[NSUserDefaults standardUserDefaults] synchronize];
	
		//because of the custom SettingsViewModel we constructed we pull the HLS value from NSUserDefaults
    self.goCoderConfig.allowHLSPlayback = [[NSUserDefaults standardUserDefaults] boolForKey:AllowHLSKey];
		self.goCoderConfig.hlsURL = [[NSUserDefaults standardUserDefaults] stringForKey:HLSURLKey];

Set play options

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syncOffset

If your source stream has a constant audio/video sync offset, use the syncOffset option to adjust how the audio/video sync is set.

-(IBAction)syncSliderChanged:(id)sender {
  UISlider *slider = (UISlider *)sender;
  Float32 value = slider.value;
  self.player.syncOffset = value;
  
}

prerollDuration

Use the prerollDuration option to set the time, in seconds, that the stream should buffer before playing.

self.player.prerollDuration = 3;  //3 second buffer.

play and stop

Use play to start playing the stream and stop to stop playing the stream.

- (IBAction) didTapPlaybackButton:(id)sender {
  if ([self.player currentPlayState] == WOWZStateIdle) {
    [self.player play:self.goCoderConfig callback:self];
  }
  else {
    [self.player stop];
  }
}

mute

Use the mute option to silence the audio of the stream.

- (IBAction)didTapMuteButton:(id)sender {
  self.player.muted = !self.player.muted;
  UIImage *muteButtonImage = [UIImage imageNamed:self.player.muted ? @"volume_mute" : @"volume_unmute"];
  [self.muteButton setImage:muteButtonImage forState:UIControlStateNormal];
  self.volumeSlider.enabled = !self.player.muted;
}

volume

Use the volume option to adjust the audio volume of the stream.

- (IBAction)didChangeVolume:(id)sender {
  UISlider *slider = (UISlider *)sender;
  self.player.volume = slider.value;
}

playerViewGravity

Use the following playerViewGravity properties to specify how the player preview should display:

Set the previewGravity mode.

self.player.playerViewGravity = WOWZPlayerViewGravityResizeAspect;

Get the bitrate during playback

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You can get the bitrate of a live stream as it's received across the network socket for playback. 

The bitrate is updated every three seconds based on the average bitrate from the start of playback to the current time.

You can get the bitrate either by using the currentInjestBitrate property in the WowzaPlayer class or by listening for the value with NSNotificationCenter.

To get the bitrate by using currentInjestBitrate:

// Get the bitrate of the stream at the network socket
self.player.currentInjestBitrate

To listen for the bitrate:

// Listen for the bitrate of the stream at the network socket
name@"WOWZBitrateUpdate" object:nil

More resources

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• GoCoder SDK Reference for iOS