Tracks & Media

Tracks are how media flows through an AxonKit room. Local tracks are published from the current client; remote tracks are subscribed from other participants.

Publishing camera & microphone

The LocalParticipant provides high-level helpers:

const lp = room.localParticipant;

await lp.setCameraEnabled(true);        // publish the default camera
await lp.setMicrophoneEnabled(true);    // publish the default microphone
await lp.setScreenShareEnabled(true);   // publish the screen

// or enable both at once
await lp.enableCameraAndMicrophone();

Publishing custom tracks

import { createLocalTracks, createLocalVideoTrack } from '@axonkit/client-sdk-js';

const tracks = await createLocalTracks({ audio: true, video: true });

for (const track of tracks) {
  await lp.publishTrack(track);
}

// unpublish (optionally stopping the underlying source)
await lp.unpublishTrack(tracks[0], true);

Factory functions include createLocalAudioTrack, createLocalVideoTrack, createLocalScreenTracks, and createLocalTracks.

Device management

await room.switchActiveDevice('videoinput', deviceId);
await room.switchActiveDevice('audioinput', deviceId);
await room.switchActiveDevice('audiooutput', deviceId);

const current = room.getActiveDevice('videoinput');

lp.lastCameraError and lp.lastMicrophoneError surface the most recent capture failure (e.g. permission denied).

Subscribing to remote tracks

Subscriptions are automatic (server-side auto-subscribe), so you mostly react to events:

room.on(RoomEvent.TrackSubscribed, (track, publication, participant) => {
  const el = track.attach();   // returns an HTMLMediaElement
  if (track.kind === 'video') {
    document.getElementById('videos')?.appendChild(el);
  } else {
    el.play();
  }
});

room.on(RoomEvent.TrackUnsubscribed, (track) => {
  track.detach();
});

track.attach() returns the media element; track.detach() removes all attached elements. A Track also exposes:

• track.isMuted — whether the track is muted
• track.streamState — Active or Paused (server-side pause)
• track.currentBitrate — current bitrate estimate

Simulcast, dynacast & adaptive stream

These are configured on the Room at construction:

const room = new Room({
  dynacast: true,       // pause simulcast layers / SVC tracks with no subscribers
  adaptiveStream: true, // adapt subscription to element size & visibility
});

• Dynacast saves publisher CPU/bandwidth when nobody needs the high layers.
• Adaptive Stream requires the video element to be in the DOM with a measurable size; it manages the subscription quality automatically.

Muting without unpublishing

Muting a local track keeps it published but stops its media (the underlying MediaStreamTrack.enabled is toggled and the producer is paused):

const [mic] = await createLocalTracks({ audio: true });

mic.mute();   // local tracks only — remote tracks cannot be muted
mic.unmute();

mute()/unmute() live on LocalTrack; remote tracks expose the read-only isMuted flag instead.

See Concepts for the underlying SFU, simulcast, and dynacast model.