README

media-player

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

Design organization buy-in

design.d2l entry

Architectural sign-off

Continuous integration

Cross-browser testing

Unit tests (if applicable)

Accessibility tests

Visual diff tests

Localization with Serge (if applicable)

Demo page

README documentation

A LitElement 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

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 & Releasing

TL;DR: Commits prefixed with fix: and feat: will trigger patch and minor releases when merged to main. Read on for more details...

The semantic-release GitHub Action is called from the release.yml GitHub Action workflow to handle version changes and releasing.

Version Changes

All version changes should obey semantic versioning rules:

MAJOR version when you make incompatible API changes,
MINOR version when you add functionality in a backwards compatible manner, and
PATCH version when you make backwards compatible bug fixes.

The next version number will be determined from the commit messages since the previous release. Our semantic-release configuration uses the Angular convention when analyzing commits:

Commits which are prefixed with fix: or perf: will trigger a patch release. Example: fix: validate input before using
Commits which are prefixed with feat: will trigger a minor release. Example: feat: add toggle() method
To trigger a MAJOR release, include BREAKING CHANGE: with a space or two newlines in the footer of the commit message
Other suggested prefixes which will NOT trigger a release: build:, ci:, docs:, style:, refactor: and test:. Example: docs: adding README for new component.

To revert a change, add the revert: prefix to the original commit message. This will cause the reverted change to be omitted from the release notes. Example: revert: fix: validate input before using.

Releases

When a release is triggered, it will:

Update the version in package.json
Tag the commit
Create a GitHub release (including release notes)
Deploy a new package to NPM

Releasing from Maintenance Branches

Occasionally you'll want to backport a feature or bug fix to an older release. semantic-release refers to these as maintenance branches.

Maintenance branch names should be of the form: +([0-9])?(.{+([0-9]),x}).x.

Regular expressions are complicated, but this essentially means branch names should look like:

1.15.x for patch releases on top of the 1.15 release (after version 1.16 exists)
2.x for feature releases on top of the 2 release (after version 3 exists)

Usage no npm install needed!