matroska-subtitles

Streaming parser for embedded .mkv subtitles.

Supported formats: .srt, .ssa, .ass.

install

$ npm install matroska-subtitles

or include it directly:

<script src="https://cdn.jsdelivr.net/npm/matroska-subtitles@3.x/dist/matroska-subtitles.min.js"></script>

example

const fs = require('fs')
const { SubtitleParser } = require('matroska-subtitles')
const parser = new SubtitleParser()
// first an array of subtitle track information is emitted
parser.once('tracks', (tracks) => console.log(tracks))
// afterwards each subtitle is emitted
parser.on('subtitle', (subtitle, trackNumber) =>
  console.log('Track ' + trackNumber + ':', subtitle))
fs.createReadStream('Sintel.2010.720p.mkv').pipe(parser)

See examples folder for more examples.

`tracks` event response format

[
  { number: 3, language: 'eng', type: 'utf8', name: 'English(US)' },
  { number: 4, language: 'jpn', type: 'ass', header: '[Script Info]\r\n...' }
]

The language attribute can be undefined if the mkv track does not specify it, this is often interpreted as eng.
The name attribute is not standard but may provide language info.

`subtitle` event response format

{
  text: 'This blade has a dark past.',
  time: 107250,  // ms
  duration: 1970 // ms
}

attached files

The parser now also has a file event that emits embedded mkv files, mainly to be used to extract embedded subtitle fonts.

parser.on('file', file => console.log('file:', file))

Output:

{
  filename: 'Arial.ttf',
  mimetype: 'application/x-truetype-font',
  data: Buffer() [Uint8Array]
}

random access

This module also includes a SubtitleStream class for intercepting subtitles
in mkv streams with support for seeking.

const { SubtitleStream } = require('matroska-subtitles')
let subtitleStream = new SubtitleStream()
subtitleStream.once('tracks', (tracks) => {
  // close the old subtitle stream and open a new at a different stream offset
  subtitleStream = new SubtitleStream(subtitleStream)
})

See examples/random-access.js for a detailed example.

license

MIT