Subscribe to Media Tracks

The agent publishes its rendered output as two separate LiveKit media tracks: one video track for the avatar and one audio track for its voice. To play the agent, listen for TrackSubscribed and attach each track to a media sink.

Note: Attach the listener before calling room.connect() so you don't miss the initial subscription events.

Subscribing to tracks

import { RoomEvent, Track } from "livekit-client";

room.on(RoomEvent.TrackSubscribed, (track) => {
  if (track.kind === Track.Kind.Video) {
    track.attach(document.getElementById("agent-video") as HTMLVideoElement);
  } else if (track.kind === Track.Kind.Audio) {
    track.attach(document.getElementById("agent-audio") as HTMLAudioElement);
  }
});

Your HTML needs a <video> and <audio> element for the tracks to attach to:

<video id="agent-video" autoplay playsinline></video>
<audio id="agent-audio" autoplay></audio>

from livekit import rtc

def on_track_subscribed(track, publication, participant):
    if track.kind == rtc.TrackKind.KIND_VIDEO:
        # Handle video frames (e.g. forward to a renderer or recorder)
        pass
    elif track.kind == rtc.TrackKind.KIND_AUDIO:
        # Handle audio frames (e.g. forward to a speaker or recorder)
        pass

room.on("track_subscribed", on_track_subscribed)

Python rendering depends on your runtime — see the LiveKit Python tracks guide for frame handling examples.

room.listener = object : RoomListener {
    override fun onTrackSubscribed(
        track: Track,
        publication: RemoteTrackPublication,
        participant: RemoteParticipant
    ) {
        when (track) {
            is VideoTrack -> {
                // Attach to a VideoView in your UI
                videoView.addRenderer(track)
            }
            is AudioTrack -> {
                // Audio plays through the default output by default
            }
        }
    }
}

Subscribing to tracks

What’s Next