What this subtitle generator does

What the tool does

You add a video or audio file, and the page turns the speech in it into timed subtitles inside your browser tab. The file is not uploaded: the site is a set of static files with no upload endpoint, and its security policy lets the page connect only to this site. The privacy and security page shows how to check that.

• Language: detected from the speech, or the one you choose from the list. Detection is checked on English only so far.
• Model: a smaller model, the default, and a larger one that is a bigger download and needs more memory. How the two compare is not measured yet.
• Preview: each subtitle shown over your video, or under your audio, at its time.
• Editing: fix the text, split a subtitle at the cursor or merge it with the next, and move a start or an end by a tenth of a second.
• Downloads: SRT and VTT (WebVTT) files, named after your video and written from your edited subtitles.

How to use it walks through each control with screenshots.

How it runs

The engine is an open-source speech recognition program compiled to WebAssembly, and it runs an open-source model, so both work in a web page on your own device. Your browser downloads them from this site, the model in checked parts, when you add your first file, and keeps them for later visits; nothing about your file goes the other way. Long recordings are read a slice at a time where your browser can decode the file that way, so the page never holds the whole file's sound at once, and the subtitles appear a few minutes of audio at a time. While it works, the page shows an estimate of the time left, measured on your device, instead of a promised speed. How it works names the model and lists every file the page downloads.

What it does not do

• Translate. The subtitles are in the language that is spoken in the file.
• Say who is speaking or describe sounds. There are no speaker labels, so the files are subtitles rather than full closed captions; you can type names or sounds into a cue yourself.
• Fetch a video from a link. The file has to be on your device; the page does not download videos from other sites.
• Listen to a microphone. It works on files, not on live sound.
• Burn subtitles into the video. You get subtitle files to load in a player, an editor, or a video platform.
• Edit a subtitle file you already have. The editor works on the subtitles the page makes.

Measured before it is described

How accurate the subtitles are, and how long they take, depends on the recording, the language, the model size, and your device. So no page on this site gives an accuracy, speed, or language figure until we have measured it on this engine. When we publish one, it will carry its date, the method, and the device it was measured on. What we do check on every change is that the pieces work: an automated browser test turns a short English recording into subtitles, edits and downloads them, and confirms that nothing leaves the page. What that test covers.

Who builds it

Subtitle Generator is built and operated by Harebell Caption Works. The site shows no ads and runs no analytics, and its pages set no cookies. The details are in the privacy policy, and the open-source software and models the page runs are listed, with their licenses, on the credits page.

Contact

Questions, suggestions, or a file the tool handled badly: write to support@subtitle-generator.online. Please describe what happened rather than attaching a private recording.