RTC Call Stats

Sometimes you need a way to capture certain metrics related to a call. This may be helpful if you want to tailor the experience to your users or debug issues. Typical metrics of interest are audio/video bitrate, round trip time, total consumed bandwidth and packet loss.

100ms SDK provides this data via certain events. These events are emitted continuously within a fixed interval of one second after a room has been joined. You can get stats:

as an overall summary by subscribing to HMSUpdateListenerActions.ON_RTC_STATS event, or
on a per track basis by subscribing to
- HMSUpdateListenerActions.ON_LOCAL_AUDIO_STATS event for local audio stats,
- HMSUpdateListenerActions.ON_LOCAL_VIDEO_STATS event for local video stats,
- HMSUpdateListenerActions.ON_REMOTE_AUDIO_STATS event for remote peers' audio stats,
- HMSUpdateListenerActions.ON_REMOTE_VIDEO_STATS event for remote peers' video stats

To get a list of all events emitted by the 100ms React Native SDK, check out Event Listener guide

Let's see how we can get Stats by subscribing to above events -

Enable Receiving Stats Events

By default, Stats Events are not sent from the native platform to React Native side. To enable receiving these events on React Native side, the enableRTCStats method must be called on HMSSDK instance.


hmsInstance.enableRTCStats();

Now, You can subscribe to stats events as per your use case:

HMSUpdateListenerActions.ON_RTC_STATS: This event provides combined stats for the Room session.
HMSUpdateListenerActions.ON_LOCAL_AUDIO_STATS: This event provides stats for local audio track.
HMSUpdateListenerActions.ON_LOCAL_VIDEO_STATS: This event provides stats for local video track with all the available layers.
HMSUpdateListenerActions.ON_REMOTE_AUDIO_STATS: This event provides stats for remote peers' audio tracks.
HMSUpdateListenerActions.ON_REMOTE_VIDEO_STATS: This event provides stats for remote peers' video tracks.


const onChangeRtcStats = (data: {
    rtcStats: HMSRTCStatsReport // `HMSRTCStatsReport` is explained in 'Supplementary bytes' section
}) => {
    console.log(data.rtcStats);
};

hmsInstance.addEventListener(HMSUpdateListenerActions.ON_RTC_STATS, onChangeRtcStats);

// This function is subscribed to `ON_LOCAL_AUDIO_STATS` event
const onChangeLocalAudioStats = (data: {
    localAudioStats: HMSLocalAudioStats, // `HMSLocalAudioStats` is explained in 'Supplementary bytes' section
    track: HMSLocalAudioTrack,
    peer: HMSPeer
}) => {
    console.log(data.localAudioStats);
};

hmsInstance.addEventListener(
    HMSUpdateListenerActions.ON_LOCAL_AUDIO_STATS,
    onChangeLocalAudioStats
);

// This function is subscribed to `ON_LOCAL_VIDEO_STATS` event
const onChangeLocalVideoStats = (data: {
    localVideoStats: HMSLocalVideoStats, // `HMSLocalVideoStats` is explained in 'Supplementary bytes' section
    track: HMSLocalVideoTrack,
    peer: HMSPeer
}) => {
    console.log(data.localVideoStats);
};

hmsInstance.addEventListener(
    HMSUpdateListenerActions.ON_LOCAL_VIDEO_STATS,
    onChangeLocalVideoStats
);

// This function is subscribed to `ON_REMOTE_AUDIO_STATS` event
const onChangeRemoteAudioStats = (data: {
    remoteAudioStats: HMSRemoteAudioStats, // `HMSRemoteAudioStats` is explained in 'Supplementary bytes' section
    track: HMSRemoteAudioTrack,
    peer: HMSPeer
}) => {
    console.log(data.remoteAudioStats);
};

hmsInstance.addEventListener(
    HMSUpdateListenerActions.ON_REMOTE_AUDIO_STATS,
    onChangeRemoteAudioStats
);

// This function is subscribed to `ON_REMOTE_VIDEO_STATS` event
const onChangeRemoteVideoStats = (data: {
    remoteVideoStats: HMSRemoteVideoStats, // `HMSRemoteVideoStats` is explained in 'Supplementary bytes' section
    track: HMSRemoteVideoTrack,
    peer: HMSPeer
}) => {
    console.log(data.remoteVideoStats);
};

hmsInstance.addEventListener(
    HMSUpdateListenerActions.ON_REMOTE_VIDEO_STATS,
    onChangeRemoteVideoStats
);

Disable Receiving Stats Events

After you are done with these stats and don't want to receive these event updates anymore. You can stop receiving these events on React Native side by calling disableRTCStats method on HMSSDK instance.


hmsInstance.disableRTCStats();

Unsubscribe from Events

Now you can also remove your event subscriptions because subscribed functions will not receive any events until you again enable receiving these events -


hmsInstance.removeEventListener(HMSUpdateListenerActions.ON_LOCAL_AUDIO_STATS);

hmsInstance.removeEventListener(HMSUpdateListenerActions.ON_LOCAL_VIDEO_STATS);

hmsInstance.removeEventListener(HMSUpdateListenerActions.ON_REMOTE_AUDIO_STATS);

hmsInstance.removeEventListener(HMSUpdateListenerActions.ON_REMOTE_VIDEO_STATS);

Supplementary bytes

HMSRTCStatsReport

This class will contain the combined stats for the Room. Interface for HMSRTCStatsReport class looks like -


interface HMSRTCStats {
    // Total bytes sent in the current session.
    bytesSent?: number;

    // Total bytes received in the current session.
    bytesReceived?: number;

    // Total packets received in the current session.
    packetsReceived?: number;

    // Total packets lost in the current session.
    packetsLost?: number;

    // Total outgoing bitrate observed since previous report.
    bitrateSent?: number;

    // Total incoming bitrate observed since previous report in Kb/s.
    bitrateReceived?: number;

    // Average round trip time observed since previous report in seconds.
    roundTripTime?: number;
}

interface HMSRTCStatsReport {
    // Summary of all video tracks
    video?: HMSRTCStats;

    // Summary of all audio tracks
    audio?: HMSRTCStats;

    // Combined audio + video values
    combined?: HMSRTCStats;
}

HMSLocalAudioStats

This class contains stats related to local audio track. Interface for HMSLocalAudioStats class looks like -


interface HMSLocalAudioStats {
    // Round trip time observed since previous report.
    roundTripTime?: number;

    // Total bytes sent by this track in the current session.
    bytesSent?: number;

    // Outgoing bitrate of this track observed since previous report in Kb/s.
    bitrate?: number;
}

HMSLocalVideoStats

This class contains stats related to local video track. Interface for HMSLocalVideoStats class looks like -


interface HMSVideoResolution {
    height?: number;
    width?: number;
}

interface HMSLocalVideoStats {
    // Round trip time observed since previous report.
    roundTripTime?: number;

    // Total bytes sent by this track in the current session.
    bytesSent?: number;

    // Outgoing bitrate of this track observed since previous report in Kb/s.
    bitrate?: number;

    // Resolution of video frames being sent.
    resolution?: HMSVideoResolution;

    // Frame rate of video frames being sent (FPS).
    frameRate?: number;
}

HMSRemoteAudioStats

This class contains stats related to remote audio track. Interface for HMSRemoteAudioStats class looks like -


class HMSRemoteAudioStats {
  // Packet Jitter measured in seconds for this track. Calculated as defined in section 6.4.1. of RFC3550.
  jitter?: number;

  // Total bytes received by this track in the current session.
  bytesReceived?: number;

  // Incoming bitrate of this track observed since previous report in Kb/s.
  bitrate?: number;

  // Total packets received by this track in the current session.
  packetsReceived?: number;

  // Total packets lost by this track in the current session.
  packetsLost?: number;
}

HMSRemoteVideoStats

This class contains stats related to remote video track. Interface for HMSRemoteVideoStats class looks like -


interface HMSVideoResolution {
  height?: number;
  width?: number;
}

class HMSRemoteVideoStats {
  // Packet Jitter measured in seconds for this track. Calculated as defined in section 6.4.1. of RFC3550.
  jitter?: number;

  // Total bytes received by this track in the current session.
  bytesReceived?: number;

  // Incoming bitrate of this track observed since previous report in Kb/s.
  bitrate?: number;

  // Total packets received by this track in the current session.
  packetsReceived?: number;

  // Total packets lost by this track in the current session.
  packetsLost?: number;

  // Resolution of video frames being received.
  resolution?: HMSVideoResolution;

  // Frame rate of video frames being received (FPS).
  frameRate?: number;
}

Connection Quality

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