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

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

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
);

hmsInstance.removeEventListener(HMSUpdateListenerActions.ON_RTC_STATS);

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;
}