Guides / Recording & Livestreaming / Track Egress

Track Egress


TrackEgress is the simplest way to export individual tracks to cloud storage or a server via WebSocket.

Tracks are exported as is, without transcoding. The following containers will be used depending on track codec:

  • H.264: MP4
  • VP8: WebM
  • Opus: Ogg

Export to cloud storage

const output = {
fileType: EncodedFileType.MP4,
filepath: 'livekit-demo/track-test.mp4',
s3: {
accessKey: 'aws-access-key',
secret: 'aws-access-secret',
region: 'aws-region',
bucket: 'my-bucket'
const info = await egressClient.startTrackEgress('my-room', output, trackID);
const egressID = info.egressId;

Stream audio to WebSocket

You can add custom stream processing by starting a TrackEgress to your WebSocket server. This will give you a real-time streaming export of your audio tracks. (WebSocket streaming is only available for audio tracks).

The tracks will be exported as raw PCM data (Content-Type audio/x-raw). This format is compatible with most transcription services.

When a TrackEgressRequest is started with a WebSocket URL, we'll initiate a WebSocket session to the desired URL.

We'll send a combination of binary and text frames. Binary frames would contain audio data. Text frames will contain end user events on the tracks. For example: if the track was muted, you will receive the following:

{ "muted": true }

And when unmuted:

{ "muted": false }

The WebSocket connection will terminate when the track is unpublished (or if the participant leaves the room).

const info = await egressClient.startTrackEgress(
const egressID = info.egressId;