chaptersTrack

Import

import { appleHlsChapters, chaptersTrack, jsonLdChapters, podcastChapters } from '@videojs/html';

chaptersTrack is a track definition for { kind: 'chapters' }. It has no label, so it matches every chapters track, from the media and the app alike. A chapter’s title is its cue’s text, and its value is typed as ChapterCueValue, which holds what chapter formats carry beyond a title.

WebVTT chapters carry only a title, so their cues have no value. Chapters converted from JSON with the functions below carry one.

Usage

import { chaptersTrack, getActiveTextCues } from '@videojs/html';

const player = document.querySelector('video-player')!;
const label = document.querySelector('.current-chapter')!;

player.store.subscribe(() => {
  const [chapter] = getActiveTextCues(player.store, chaptersTrack);
  label.textContent = chapter?.text ?? '';
});

Chapter formats

Each converter takes a file’s text, or JSON you already parsed, and returns cues for a chapters track. Pass one as the format of a track with a src, and the player converts the file once it loads. Or call it yourself and pass the result as cues. Converters skip entries they can’t read; only text that isn’t JSON throws.

player.store.addTextTrack({ kind: 'chapters', src: '/episodes/42/chapters.json', format: podcastChapters });

A chapter without an end runs to the next chapter, and the last one to the end of the media.

podcastChapters

Reads a Podcasting 2.0 JSON chapters file. Each chapter’s title becomes the cue text, startTime and endTime its times, url its url, and img its first image. Chapters marked toc: false are left out, since they aren’t meant to be shown.

appleHlsChapters

Reads an Apple HLS chapters file: the JSON an EXT-X-SESSION-DATA tag with DATA-ID="com.apple.hls.chapters" points to. Each chapter starts at its start-time and ends after its duration. Its first title becomes the cue text, and every title is kept in titles by language. Its images keep their pixel-width and pixel-height as width and height.

jsonLdChapters

Reads schema.org JSON-LD: a VideoObject whose hasPart lists Clips, a list of Clips, or one Clip. These are the clips Google shows as key moments. Each clip’s name becomes the cue text, startOffset and endOffset its times in seconds, and its description, url, and first thumbnailUrl its value.

const jsonLd = document.querySelector('script[type="application/ld+json"]')!.textContent!;

player.store.addTextTrack({ kind: 'chapters', cues: jsonLdChapters(jsonLd) });

Exports