Live Audio Streaming

Connect to WebRTC streams to receive live audio from emergency calls. We recommend using LiveKit's SDKs for the easiest integration.

Prerequisites

• incident_events scope (see Authentication)
• Incident ID (typically received via webhook)

How to Connect

1. Obtain an incident ID (usually provided via a webhook)
2. Retrieve a stream token
3. Connect to the WebRTC stream using LiveKit

Example: Connect with LiveKit

import { Room } from "livekit-client";

// Create a room
const room = new Room({
  /* options */
});

// Connect using your stream token
await room.connect(API_STREAM_URL, token);

Full implementation details are in LiveKit's documentation.

Live Scrubbing

Control playback during a live session using WebRTC data channels.

Command Messages

Send commands to control the audio stream:

type CommandMessage = {
  cmd: 'scrub' | 'pause' | 'resume' | 'scrub-to-end' | 'set-gain';
  position?: number;    // milliseconds from call start
  gain?: number;        // gain in dB
  callerType?: 'caller' | 'callTaker';
};

Examples:

// Pause playback
{ "cmd": "pause" }

// Resume playback
{ "cmd": "resume" }

// Scrub to position (10ms from start)
{ "cmd": "scrub", "position": 10 }

// Jump to live position
{ "cmd": "scrub-to-end" }

// Adjust volume
{ "cmd": "set-gain", "gain": 11.2, "callerType": "caller" }

Sending commands with LiveKit:

const strData = JSON.stringify({ cmd: "scrub", position: 10 });
const encoder = new TextEncoder();
const data = encoder.encode(strData);
room.localParticipant.publishData(data, DataPacket_Kind.RELIABLE);

Data Messages

Receive status updates about the stream:

type DataMessage = {
  kind: 'status';
  position: number;   // milliseconds from call start
  duration: number;   // call duration (updates for live calls)
  paused: boolean;    // whether playback is paused
  atEnd: boolean;     // whether cursor is at call end
  callOver: boolean;  // whether the 911 call has ended
};

Receiving data messages:

room.on(RoomEvent.DataReceived, (payload: Uint8Array) => {
  const decoder = new TextDecoder();
  const strData = decoder.decode(payload);
  const data = JSON.parse(strData);

  console.log(`Position: ${data.position}ms, Duration: ${data.duration}ms`);
});

See LiveKit data messages documentation for more details.

Playback (Recorded Calls)

For recorded calls, join the WebRTC session the same way as live calls. The differences are:

1. Playback cursor starts at position 0
2. Playback is paused by default

All commands and APIs work identically.

AutoPlay Option

Configure autoplay when creating the stream token:

Setting	Behavior
autoplay: true (default)	Audio starts at the most recent position
autoplay: false	Audio pauses at the beginning; send resume to start

Set autoplay: false to ensure important audio at the start of a call isn't missed.