media-player

Note: this is a "labs" component. While functional, these tasks are prerequisites to promotion to BrightspaceUI "official" status:

• [ ] Design organization buy-in
• [ ] Architectural sign-off
• [x] Continuous integration
• [x] Cross-browser testing
• [x] Unit tests (if applicable)
• [x] Accessibility tests
• [x] Visual diff tests
• [x] Localization with Serge (if applicable)
• [x] Demo page
• [x] README documentation

A Lit element based media player component, designed for similarity across browsers. Capable of playing video and audio content.

Displaying video

Displaying audio

Installation

To install from NPM:

npm install @brightspace-ui-labs/media-player

d2l-labs-media-player

<script type="module">
    import '@brightspace-ui-labs/media-player/media-player.js';
</script>
<d2l-labs-media-player src="/video.webm"></d2l-labs-media-player>

Attributes:

<!-- Render a media player with a source file and loop the media when it reaches the end -->

<d2l-labs-media-player loop src="./local-video.mp4"></d2l-labs-media-player>

Properties:

// Programatically determine the current playback time of the media player

console.log(`Current playback time of the media player = ${this.document.querySelector('d2l-labs-media-player').currentTime} sec`);

Methods:

// Programatically pause the media player

this.document.querySelector('d2l-labs-media-player').pause();

Events:

// Listen for the loadeddata event

this.document.querySelector('d2l-labs-media-player').addEventListener('loadeddata', () => {
	console.log('loadeddata event has been dispatched');
});

Multiple qualities using <source>

The media player supports switching to different qualities. If multiple <source> tags are present, a quality selector will be available in the menu. In this case, do not set src on d2l-labs-media-player.

<d2l-labs-media-player>
  <source src="sample-video-144p.mp4" label="SD">
  <source src="sample-video.mp4" label="HD" default>
</d2l-labs-media-player

Attributes

Showing thumbnails preview with thumbnails attribute

Provide a url to the thumbnails sprite image. This sprite is a grid of images taken from the video, at a set interval.

e.g. sample video thumbnails sprite

The thumbnail file name must use the following format: th<height>w<width>i<interval>-<hash>.[png|jpg]

• width and height are the width/height px of each individual thumbnail
• interval indicates how many seconds apart each thumbnail is

For example, a sprite image named th90w160i5-<hash>png has the thumbnails 5 seconds apart, with width 160px and height 90px.

Chapters with metadata attribute

Provide metadata JSON e.g. getMetadata endpoint

Example format:

{
    "cuts": [
      "in": 20,
      "out": 30
    ],
    "chapters": [
      {
        "time": 0,
        "title": {
          "en": "Chapter One",
          "fr": "Chapitre Un"
        }
      },
      {
        "time": 30,
        "title": {
          "en": "Chapter Two",
          "fr": "Chapitre Deux"
        }
      },
      {
        "time": 70,
        "title": {
          "en": "Chapter Three",
          "fr": "Chapitre Trois"
        }
      }
    ]
}

Captions and Subtitles Using <track>

The media player supports captions and subtitles, provided as .srt or .vtt files. If any valid tracks are present, a captions menu will be presented in the settings menu with an item for each track.

<script type="module">
    import '@brightspace-ui-labs/media-player/media-player.js';
</script>
<d2l-labs-media-player src="/video.webm">
	<track src="/english-captions.srt" srclang="en" label="English" kind="captions">
	<track src="/french-captions.vtt" srclang="fr" label="French" kind="captions">
</d2l-labs-media-player>

Attributes

Local Storage

The media player uses local storage to persist the user's playback speed, track selections, and volume.

Items

Accessibility

The following features are implemented to improve accessibility:

• all controls can be accessed using the mouse or keyboard
• captions can be provided to the media player
• important events, such as a media source failing to load, are displayed visually and announced by screen readers

Developing, Testing and Contributing

After cloning the repo, run npm install to install dependencies.

Running the demos

To start a @web/dev-server that hosts the demo page and tests:

npm start

Troubleshooting Common Issues

• Captions fail to load due to a "Protocols, domains, and ports must match" error
  • Solution: Set the Media Player's crossorigin property to the appropriate value (either "anonymous" or "use-credentials").
  • Explanation: If your captions sources are on a different origin, CORS needs to be enabled on the <video>/<audio> element. Otherwise, the browser will block requests to that origin due to the security measures outlined in the same-origin policy. The Media Player passes its crossorigin property directly to the <video>/<audio> element's crossorigin attribute, which sets the CORS policy. (If the crossorigin attribute isn't defined, CORS will not be used at all.)

Linting

# eslint and lit-analyzer
npm run lint

# eslint only
npm run lint:eslint

# lit-analyzer only
npm run lint:lit

Testing

# lint & run headless unit tests
npm test

# unit tests only
npm run test:headless

# debug or run a subset of local unit tests
npm run test:headless:watch

Visual Diff Testing

This repo uses the @brightspace-ui/visual-diff utility to compare current snapshots against a set of golden snapshots stored in source control.

The golden snapshots in source control must be updated by the visual-diff GitHub Action. If a pull request results in visual differences, a draft pull request with the new goldens will automatically be opened against its branch.

To run the tests locally to help troubleshoot or develop new tests, first install these dependencies:

npm install @brightspace-ui/visual-diff@X mocha@Y puppeteer@Z  --no-save

Replace X, Y and Z with the current versions the action is using.

Then run the tests:

# run visual-diff tests
npx mocha './test/**/*.visual-diff.js' -t 10000
# subset of visual-diff tests:
npx mocha './test/**/*.visual-diff.js' -t 10000 -g some-pattern
# update visual-diff goldens
npx mocha './test/**/*.visual-diff.js' -t 10000 --golden

Versioning and Releasing

This repo is configured to use semantic-release. Commits prefixed with fix: and feat: will trigger patch and minor releases when merged to main.

To learn how to create major releases and release from maintenance branches, refer to the semantic-release GitHub Action documentation.