srt2vtt-js

Convert SubRip (.srt) subtitles to WebVTT in Node.js or a browser.

Installation

npm install srt2vtt-js

Node API

import { convert } from "srt2vtt-js";

const vtt = convert(srtString);

convert(srtString, options) returns a string beginning with WEBVTT. Options are:

Option	Default	Description
sanitize	true	Escape &, <, and > in cue text.
allowVttMarkup	false	Preserve known safe VTT tags while sanitizing.
preserveCueIds	true	Keep cue identifier lines.
strict	false	Return {vtt, errors} instead of a string; invalid cues are reported.

Browser API

Import browser helpers separately:

import { url, revokeUrl, run } from "srt2vtt-js/browser";

const blobUrl = url(srtString);
// use blobUrl as a <track src>, then:
revokeUrl(blobUrl);
await run({ onTrackConverted: (track, convertedUrl) => console.log(convertedUrl) });

run() fetches every SRT <track> inside every <video> and replaces its source. The subtitle URL must be fetchable by the browser and return HTTP 200; configure CORS on the subtitle server. Network and conversion errors are passed to onError.

Subtitle files are untrusted input. Sanitization is enabled by default; only enable allowVttMarkup for trusted content.

CLI

srt2vtt input.srt
srt2vtt input.srt -o output.vtt
srt2vtt input.srt --no-sanitize

Invalid input exits non-zero. Without -o, output is written to stdout.

CDN / legacy browser script

The root srt2vtt.js is the compatibility IIFE and exposes window.srt2vtt.convert, .url, .run, and .revokeUrl. A built copy is also available at dist/iife/browser.global.js after npm run build.

<script src="https://cdn.jsdelivr.net/gh/faizath/srt2vtt.js@main/srt2vtt.js"></script>
<script>const vtt = srt2vtt.convert(srtText);</script>

Development

npm test
npm run build

MIT licensed. See LICENSE, NOTICE, and SECURITY.md.