Client Observability

Enabling sender-side statistics

To receive sender-side statistics, enable them for the stream’s publisher by passing the publishSenderStats property set to true in the OT.initPublisher call:

const publisher = OT.initPublisher({
  publishSenderStats: true
});

If publishSenderStats is not enabled, no sender statistics channel will be published for this publisher. The default value is false.

When initializing the Publisher object, set the audioFallback property of the option you pass into the OT.initPublisher() method:

Subscribing to sender-side statistics

Subscribers automatically receive sender statistics only if the publisher has enabled them and if the user calls Subscriber.getStats() at least once. Note that due to network latency, the first call to getStats may not include sender statistics. Subsequent calls are more likely to return this data.

No additional events or methods are required; the sender statistics are included in the existing stats object returned by getStats().

Receiving statistics events

Sender-side statistics are included as an optional senderStats object inside the stats object passed to the Subscriber.getStats() callback. The senderStats object contains two properties:

• connectionMaxAllocatedBitrate — The maximum bitrate that can be estimated for the connection (in bits per second)

• connectionEstimatedBandwidth — The current estimated bandwidth for the connection (in bits per second)

These two metrics are calculated per audio-video bundle, so the same values appear in both video and audio statistics. Because they reflect the transport rather than individual tracks, the metrics are shared across both audio and video.

subscriber.getStats((stats) => {
  console.log(`Packets received: ${stats.videoPacketsReceived}`);
  console.log(`Packets lost: ${stats.videoPacketsLost}`);
  console.log(`Bytes received: ${stats.videoBytesReceived}`);
  console.log(`Timestamp: ${stats.timestamp}`);

  if (stats.senderStats) {
    console.log(`Connection max allocated bitrate: ${stats.senderStats.connectionMaxAllocatedBitrate} bps`);
    console.log(`Connection current estimated bandwidth: ${stats.senderStats.connectionEstimatedBandwidth} bps`);
  } else {
    console.log("Sender stats not available yet.");
  }
});

Known issues

In some cases, when the session is relayed —or in certain routed setups with only two participants— and the Publisher uses Firefox, sender-side statistics may not be available due to browser limitations.

Enabling sender-side statistics

To receive sender-side statistics, enable them for the stream’s publisher by setting the senderStatisticsTrack property to true when building the publisher:

Publisher publisher = new Publisher.Builder(context)
        .senderStatsTrack(true) // Enable sender-side stats
        .build();

If senderStatsTrack is not enabled, no sender statistics channel will be published for this publisher. The default value is false.

Subscribing to sender-side statistics

Subscribers automatically receive sender statistics only if the publisher has enabled them and if the subscriber registers a listener for network statistics events.

You can subscribe to video and audio stats using the corresponding listener interfaces:

subscriber.setVideoStatsListener((subscriber, stats) -> {  
    // Received stats  
});  
  
subscriber.setAudioStatsListener((subscriber, stats) -> {  
    // Received stats  
});

Receiving statistics events

Sender-side statistics are delivered via the SubscriberKit.VideoStatsListener and SubscriberKit.AudioStatsListener callbacks for video and audio. The SubscriberKit.SubscriberVideoStats and SubscriberKit.SubscriberAudioStats classes each include these properties:

• connectionMaxAllocatedBitrate — The maximum bitrate that can be estimated for the connection

• connectionEstimatedBandwidth — The current estimated bitrate for the connection

These two metrics are calculated per audio-video bundle, so the same values appear in both video and audio statistics. Because they reflect the transport rather than individual tracks, the metrics are shared across both audio and video.

The stats object includes an optional senderStats field that provides the sender-side statistics. For example, when using SubscriberKit.setVideoStatsListener(), the stats parameter is a SubscriberKit.SubscriberVideoStats object:

subscriber.setVideoStatsListener((subscriber, stats) -> {  
    Log.d(TAG, "Packets received: " + stats.videoPacketsReceived);  
    Log.d(TAG, "Packets lost: " + stats.videoPacketsLost);  
    Log.d(TAG, "Bytes received: " + stats.videoBytesReceived);  
    Log.d(TAG, "Timestamp: " + stats.timeStamp);  
  
    if (stats.senderStats != null) {  
        Log.d(TAG, "Connection max allocated bitrate: " + stats.senderStats.connectionMaxAllocatedBitrate);
        Log.d(TAG, "Connection current estimated bandwidth: " + stats.senderStats.connectionEstimatedBandwidth);
    } else {  
        Log.d(TAG, "Sender stats not available yet.");  
    }  
});

The same applies to audio stats using SubscriberKit.AudioStatsListener.

Enabling sender-side statistics

To receive sender-side statistics, enable them for the stream’s publisher by setting the senderStatsTrack property to true for the OTPublisherKitSettings object used to create the publisher.

let settings = OTPublisherSettings()
settings.senderStatsTrack = true   // Enable sender-side stats

let publisher = OTPublisher(delegate: self, settings: settings)

If senderStatsTrack is not enabled, no sender statistics channel will be published for this publisher. The default value is false.

Subscribing to sender-side statistics

To receive sender statistics, set the networkStatsDelegate for a subscriber:

let subscriber = OTSubscriber(stream: stream, delegate: self)
subscriber?.networkStatsDelegate = self

Then implement the listener for either video or audio stats:

extension MyAppController: OTSubscriberKitNetworkStatsDelegate {
    func subscriber(_ subscriber: OTSubscriberKit, videoNetworkStatsUpdated stats: OTSubscriberKitVideoNetworkStats) {
        guard let senderStats = stats.senderStats else { return }
        // Use stats
    }
    func subscriber(_ subscriber: OTSubscriberKit, audioNetworkStatsUpdated stats: OTSubscriberKitAudioNetworkStats) {
        guard let senderStats = stats.senderStats else { return }
        // Use stats
    }
}

Receiving statistics events

The OTSubscriberKitNetworkStatsDelegate callbacks for video and audio deliver sender-side statistics, as shown above. The OTSenderStats, included as the senderStats member in both OTSubscriberKitVideoNetworkStats and OTSubscriberKitAudioNetworkStats, provides two properties:

• connectionMaxAllocatedBitrate — The maximum bitrate estimated for the connection
• connectionEstimatedBandwidth — The current estimated bandwidth for the connection

These two metrics are calculated per audio-video bundle, so the same values appear in both video and audio statistics. Because they reflect the transport rather than individual tracks, the metrics are shared across both audio and video.

extension MyAppController: OTSubscriberKitNetworkStatsDelegate {
    func subscriber(_ subscriber: OTSubscriberKit, videoNetworkStatsUpdated stats: OTSubscriberKitVideoNetworkStats) {
        guard let senderStats = stats.senderStats else { return }
        print("Sender max allocated bitrate: \(senderStats.connectionMaxAllocatedBitrate)")
        print("Sender current estimated bandwidth: \(senderStats.connectionEstimatedBandwidth)")
    }
}

Sample app

See the vonage-video-ios-sdk-samples sender-side statistics sample.

Enabling sender-side statistics

To receive sender-side statistics, enable them for the stream’s publisher by setting the senderStatsTrack property to true for the OTPublisherKitSettings object used to create the publisher.

OTPublisherKitSettings *settings = [[OTPublisherKitSettings alloc] init];
settings.senderStatsTrack = YES;

OTPublisher *publisher = [[OTPublisher alloc] initWithDelegate:self
                                                      settings:settings];

If senderStatsTrack is not enabled, no sender statistics channel will be published for this publisher. The default value is NO.

Subscribing to sender-side statistics

Subscribers automatically receive sender-side statistics when you register a listener for either video or audio stats.

Example: enabling video stats subscription with sender-side fields:

// In your .h or class extension: adopt the protocol
@interface MyViewController () <OTSubscriberKitNetworkStatsDelegate>
@end

// When creating the OTSubscriber:
OTSubscriber *subscriber = [[OTSubscriber alloc] initWithStream:stream delegate:self];
subscriber.networkStatsDelegate = self;
NSError *err = nil;
[session subscribe:subscriber error:&err];

Implement the delegate method for video stats:

- (void)subscriber:(OTSubscriberKit *)subscriber
videoNetworkStatsUpdated:(OTSubscriberKitVideoNetworkStats *)stats
{
    NSLog(@"Video packets received: %llu", (unsigned long long)stats.videoPacketsReceived);
    NSLog(@"Video packets lost: %llu", (unsigned long long)stats.videoPacketsLost);
    NSLog(@"Video bytes received: %llu", (unsigned long long)stats.videoBytesReceived);
    NSLog(@"Timestamp (ms): %llu", (unsigned long long)stats.timestamp);

    // The property may be nil if no sender statistics have been received yet.
    if (stats.senderStats) {
        OTSenderStats *sender = stats.senderStats;
        NSLog(@"Connection max allocated bitrate: %lld bps", (long long)sender.connectionMaxAllocatedBitrate);
        NSLog(@"Connection current estimated bandwidth: %lld bps", (long long)sender.connectionEstimatedBandwidth);
    } else {
        NSLog(@"Sender-side stats not available yet.");
    }
}

Similarly implement -subscriber:audioNetworkStatsUpdated: for audio stats, which also includes a senderStats property.

Receiving statistics events

Sender-side statistics are delivered via the OTSubscriberKitNetworkStatsDelegate callbacks for video and audio, as shown above. The OTSenderStats, included as the senderStats member in both OTSubscriberKitVideoNetworkStats and OTSubscriberKitAudioNetworkStats, provides two properties:

• connectionMaxAllocatedBitrate — The maximum bitrate that can be estimated for the connection
• connectionEstimatedBandwidth — The current estimated bandwidth for the connection

These two metrics are calculated per audio-video bundle, so the same values appear in both video and audio statistics. Because they reflect the transport rather than individual tracks, the metrics are shared across both audio and video.

Enabling sender-side statistics

To receive sender-side statistics, enable them for the stream’s publisher by setting the HasSenderStatsTrack property to true when building the publisher:

var publisherBuilder = new Publisher.Builder()
{
    HasSenderStatsTrack = true
};

Publisher publisher = publisherBuilder.Build();

If HasSenderStatsTrack is not enabled, no sender statistics channel will be published for this publisher. The default value is false.

Subscribing to sender-side statistics

Subscribers automatically receive sender statistics only if the publisher has enabled them and if the subscriber registers a listener for network statistics events.

You can subscribe to video and audio stats using the corresponding event handlers:

subscriber.VideoStatsUpdated += (sender, stats) => 
{
    // Received video stats
};

subscriber.AudioStatsUpdated += (sender, stats) => 
{
    // Received audio stats
};

Receiving statistics events

Sender-side statistics are delivered via the VideoStatsUpdated and AudioStatsUpdated events for video and audio. The SenderStats class, included in both VideoNetworkStatsEventArgs and AudioNetworkStatsEventArgs, provides two properties:

• ConnectionMaxAllocatedBitrate — The maximum bitrate that can be estimated for the connection

• ConnectionEstimatedBandwidth — The current estimated bandwidth for the connection

These two metrics are calculated per audio-video bundle, so the same values appear in both video and audio statistics. Because they reflect the transport rather than individual tracks, the metrics are shared across both audio and video.

Inside the stats event handlers, you can access the sender-side metrics through the optional SenderStats property:

subscriber.VideoStatsUpdated += (sender, stats) =>
{
    Console.WriteLine($"Packets received: {stats.PacketsReceived}");
    Console.WriteLine($"Packets lost: {stats.PacketsLost}");
    Console.WriteLine($"Bytes received: {stats.BytesReceived}");
    Console.WriteLine($"Timestamp: {stats.Timestamp}");

    if (stats.SenderStats != null)
    {
        Console.WriteLine($"Connection max allocated bitrate: {stats.SenderStats.ConnectionMaxAllocatedBitrate}");
        Console.WriteLine($"Connection current estimated bandwidth: {stats.SenderStats.ConnectionEstimatedBandwidth}");
    }
    else
    {
        Console.WriteLine("Sender stats not available yet.");
    }
};

The same approach applies to audio stats using the AudioStatsUpdated event.

Enabling sender-side statistics

To receive sender-side statistics, enable them for the stream’s publisher by calling otc_publisher_settings_set_sender_stats_track() function before constructing the publisher:

otc_publisher_settings* settings = otc_publisher_settings_new();
otc_publisher_settings_set_sender_stats_track(settings, OTC_TRUE);

otc_publisher* publisher = otc_publisher_new_with_settings( &publisher_callbacks, settings);

If the sender stats track is not enabled, no sender statistics channel will be published for this publisher. The default value is OTC_FALSE.

Subscribing to sender-side statistics

Subscribers automatically receive sender statistics when you register for the subscriber’s video or audio statistics callbacks and the publisher is sending them.

Example: enabling video statistics subscription with sender-side fields:

subscriber_callbacks.on_video_stats = on_video_stats;
otc_subscriber* subscriber = otc_subscriber_new(stream, &subscriber_callbacks);

otc_session_subscribe(session, subscriber);

Receiving statistics events

Sender-side statistics are delivered as part of the existing subscriber stats callbacks. Specific fields are included in the otc_subscriber_video_stats and otc_subscriber_audio_stats structures:

• sender_connection_max_allocated_bitrate — The maximum bitrate that can be estimated for the connection
• sender_connection_estimated_bandwidth — The current estimated bandwidth for the connection

These two metrics are calculated per audio-video bundle, so the same values appear in both video and audio statistics. Because they reflect the transport rather than individual tracks, the metrics are shared across both audio and video.

static void on_video_stats(otc_subscriber* subscriber,
                           void* user_data,
                           struct otc_subscriber_video_stats stats) {
    printf("Packets received: %llu\n", (unsigned long long)stats.packets_received);
    printf("Packets lost: %llu\n", (unsigned long long)stats.packets_lost);
    printf("Bytes received: %llu\n", (unsigned long long)stats.bytes_received);
    printf("Timestamp: %llu ms\n", (unsigned long long)stats.timestamp);
    printf("Connection max allocated bitrate: %lld bps\n", (long long)stats.sender_connection_max_allocated_bitrate);
    printf("Connection estimated bandwidth: %lld bps\n", (long long)stats.sender_connection_estimated_bandwidth);
}