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.

see also

mkv-subtitle-extractor

license

MIT