Configure and monitor a broadcast with GoCoder SDK for iOS

You can use the WowzaConfig class in the Wowza GoCoder™ SDK for iOS to configure properties for a live streaming broadcast. There are three primary categories of properties: video, audio, and connection properties for the Wowza Streaming Cloud™ service and Wowza Streaming Engine™ media server software.

You can also use the WowzaGoCoder class to get the bitrate of an encoded live stream as it is being transmitted across the network socket during a broadcast.

Contents

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Configure the stream Use the configuration presets
Get the bitrate during a broadcast
More resources

Configure the stream

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Configure the video

Use the following properties to configure the video stream:

The following example demonstrates how to use the video properties:

// Get a copy of the active config
WowzaConfig broadcastConfig = self.goCoder.config;

// Set the frame rate to 15 fps
broadcastConfig.videoFrameRate = 15;  
// Set the keyframe interval to 10 frames
broadcastConfig.videoKeyFrameInterval = 10;  
// Set the bitrate to 2.5 kbps
broadcastConfig.videoBitrate = 2500;

// Update the active config
self.goCoder.config = broadcastConfig;

Configure the audio

Use the following properties to configure the audio stream:

The following example shows how to use the audio properties:

// Get a copy of the active config
WowzaConfig broadcastConfig = self.goCoder.config;

// Set the sample rate to 22.1 kHz
broadcastConfig.audioSampleRate = 22100;  

// Update the active config
self.goCoder.config = broadcastConfig;

Configure the connection

Use the following properties to configure the connection to your Wowza Streaming Engine server or to a Wowza Streaming Cloud live stream:

The following example shows how to use the connection properties:

// Get a copy of the active config
WowzaConfig broadcastConfig = self.goCoder.config;

// Set the hostname
broadcastConfig.hostAddress = @"live.someserver.net";
// Set the name of the stream
broadcastConfig.streamName = @"someStreamName";

// Update the active config
self.goCoder.config = broadcastConfig;

Use configuration presets

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Alternatively, configure your broadcast with one of the following presets, which accommodate common frame sizes:

The following example shows how to use a frame-size preset:

// Get a copy of the active config
WowzaConfig broadcastConfig = self.goCoder.config;

// Set the defaults for 720p video
[broadcastConfig loadPreset:WOWZFrameSizePreset1280x720];

// Update the active config
self.goCoder.config = broadcastConfig;

Get the bitrate during a broadcast

You can get the bitrate of the encoded live stream as it is being transmitted across the network socket. Note that this bitrate can vary due to:

• Factors related to encoding the stream
• Automatic reduction of the stream bitrate ("throttling") to adjust for insufficient network bandwidth

The bitrate is updated every three seconds based on the average bitrate during the last 15 seconds.

You can get the bitrate by using the getCurrentBroadcastingNetworkBitrateThroughput method in the WowzaGoCoder class or by listening for the value with NSNotificationCenter.

To get the bitrate by using getCurrentBroadcastingNetworkBitrateThroughput

// Get the bitrate of the stream at the network socket
[self.goCoder getCurrentBroadcastingNetworkBitrateThroughput];

To listen for the bitrate

1. Add an observer of WOWZBroadcastBitrateNetworkThroughputUpdate notifications. For example:
    

   [[NSNotificationCenter defaultCenter] addObserver:self 
       selector:@selector(broadcastBitrateUpdated:)
       name:@"WOWZBroadcastBitrateNetworkThroughputUpdate"
       object:nil];

2. Add the selector method that will respond when WOWZBroadcastBitrateNetworkThroughputUpdate notifications are received. The notification's payload will provide the bitrate value using the broadcastThroughputBitrate key. For example:
    

   -(void) broadcastBitrateUpdated:(NSNotification *)note
   {
       dispatch_async(dispatch_get_main_queue(), ^{
           self.bitrateLabel.text = [NSString stringWithFormat:@"%.02f kbps", 
           [note.userInfo[@"broadcastThroughputBitrate"] floatValue]];
       });
   }
   
   

More resources

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• GoCoder SDK reference documentation for iOS