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@moq/watch provides a Web Component and JavaScript API for subscribing to and displaying MoQ broadcasts.

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Installation

npm install @moq/watch

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Package Information

  • Version: 0.2.2
  • License: MIT OR Apache-2.0
  • Repository: github:moq-dev/moq
  • Dependencies: @moq/hang, @moq/lite, @moq/signals, @moq/ui-core

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Web Component Usage

The easiest way to watch MoQ streams is using the <moq-watch> web component.
1

Import the element

import "@moq/watch/element";
Or use a CDN:
<script type="module" src="https://unpkg.com/@moq/watch/dist/element.js"></script>
2

Add to HTML

<moq-watch 
  url="https://relay.quic.video"
  fingerprint="https://relay.quic.video/fingerprint"
  broadcast="my-stream">
</moq-watch>
3

Style the component

moq-watch {
  width: 100%;
  height: 100%;
  display: block;
}

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Web Component API

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Attributes

<moq-watch
  url="https://relay.quic.video"
  fingerprint="https://relay.quic.video/fingerprint"
  broadcast="my-stream"
  token="eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9..."
  muted="true"
  autoplay="true"
  controls="true">
</moq-watch>
AttributeTypeDescription
urlstringWebTransport URL of the MoQ relay
fingerprintstringURL to relay’s certificate fingerprint
broadcaststringName of the broadcast to watch
tokenstringOptional JWT authentication token
mutedbooleanStart muted (default: false)
autoplaybooleanAuto-play on load (default: true)
controlsbooleanShow video controls (default: true)

​
Properties

const watch = document.querySelector("moq-watch");

// Connection state
console.log(watch.connected); // boolean
console.log(watch.error); // Error | null

// Playback state
console.log(watch.playing); // boolean
console.log(watch.muted); // boolean

// Media info
console.log(watch.tracks); // Track[]
console.log(watch.catalog); // Catalog | null

​
Methods

const watch = document.querySelector("moq-watch");

// Playback control
watch.play();
watch.pause();
watch.mute();
watch.unmute();

// Connection control
await watch.connect();
watch.disconnect();

​
Events

const watch = document.querySelector("moq-watch");

// Connection events
watch.addEventListener("connected", () => {
  console.log("Connected to relay");
});

watch.addEventListener("disconnected", () => {
  console.log("Disconnected from relay");
});

watch.addEventListener("error", (e) => {
  console.error("Error:", e.detail);
});

// Playback events
watch.addEventListener("play", () => {
  console.log("Playback started");
});

watch.addEventListener("pause", () => {
  console.log("Playback paused");
});

// Media events
watch.addEventListener("catalog", (e) => {
  console.log("Catalog received:", e.detail);
});

watch.addEventListener("track", (e) => {
  console.log("Track announced:", e.detail);
});

​
JavaScript API

For more control, use the JavaScript API directly: 
import * as Watch from "@moq/watch";
import * as Connection from "@moq/lite/Connection";

// Connect to relay
const conn = await Connection.connect({
  url: "https://relay.quic.video",
  fingerprint: "https://relay.quic.video/fingerprint"
});

// Subscribe to broadcast
const subscriber = await conn.subscribe("my-stream");

// Create watch instance
const watch = new Watch.Broadcast({
  subscriber: subscriber,
  video: videoElement,
  audio: audioContext
});

// Start watching
await watch.start();

​
Broadcast API

import { Broadcast } from "@moq/watch";

const broadcast = new Broadcast({
  subscriber: subscriber,
  video: videoElement,
  audio: audioContext
});

// Start/stop
await broadcast.start();
broadcast.stop();

// State
const state = broadcast.state; // Signal<BroadcastState>
state.subscribe(s => {
  console.log("State:", s);
});

​
Video API

import * as Video from "@moq/watch/Video";

const video = new Video.Decoder({
  track: videoTrack,
  catalog: catalogInfo,
  canvas: canvasElement
});

await video.start();

// Video state
video.state.subscribe(state => {
  console.log("Frames decoded:", state.framesDecoded);
  console.log("Frames dropped:", state.framesDropped);
});

​
Audio API

import * as Audio from "@moq/watch/Audio";

const audio = new Audio.Decoder({
  track: audioTrack,
  catalog: catalogInfo,
  context: audioContext
});

await audio.start();

// Audio state
audio.state.subscribe(state => {
  console.log("Samples decoded:", state.samplesDecoded);
});

​
Chat API

import * as Chat from "@moq/watch/Chat";

const chat = new Chat.Receiver({
  track: chatTrack
});

chat.messages.subscribe(messages => {
  for (const msg of messages) {
    console.log(`${msg.author}: ${msg.text}`);
  }
});

​
Complete Example

Here’s a complete HTML page: 
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>MoQ Watch Example</title>
  <style>
    body {
      margin: 0;
      padding: 0;
      background: #000;
    }
    
    moq-watch {
      width: 100vw;
      height: 100vh;
      display: block;
    }
  </style>
</head>
<body>
  <moq-watch 
    url="https://relay.quic.video"
    fingerprint="https://relay.quic.video/fingerprint"
    broadcast="demo">
  </moq-watch>
  
  <script type="module">
    import "@moq/watch/element";
    
    const watch = document.querySelector("moq-watch");
    
    watch.addEventListener("connected", () => {
      console.log("Connected!");
    });
    
    watch.addEventListener("error", (e) => {
      console.error("Error:", e.detail);
    });
    
    watch.addEventListener("catalog", (e) => {
      console.log("Tracks:", e.detail.tracks);
    });
  </script>
</body>
</html>

​
TypeScript Example

import "@moq/watch/element";
import type { MoqWatch } from "@moq/watch/element";

// Type-safe element access
const watch = document.querySelector("moq-watch") as MoqWatch;

watch.url = "https://relay.quic.video";
watch.fingerprint = "https://relay.quic.video/fingerprint";
watch.broadcast = "my-stream";

await watch.connect();

​
UI Customization

The watch component includes a Solid.js UI that can be customized: 
import { Watch } from "@moq/watch/ui";
import { render } from "solid-js/web";

const app = document.getElementById("app");

render(() => (
  <Watch 
    url="https://relay.quic.video"
    fingerprint="https://relay.quic.video/fingerprint"
    broadcast="my-stream"
    theme="dark"
  />
), app);
See @moq/ui-core for theming options.

​
Browser Support

Requires:
  • WebTransport API (Chrome 97+, Edge 97+, Opera 83+)
  • WebCodecs API (Chrome 94+, Edge 94+, Opera 80+)

​
Next Steps

@moq/publish

Publish streams to watch

@moq/hang

Learn about the media layer

@moq/ui-core

Customize the UI theme

@moq/lite

Use the low-level protocol API

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