Convert video to SRT subtitles

Upload MP4, MOV, or WEBM and get a timed SRT back. The audio is extracted in your browser first, so a large video never needs a full upload.

Why the upload is small

Subtitles only need the audio. Rather than sending a multi-gigabyte video across the network, the browser plays the file locally, captures the audio track, and re-encodes it to a compressed 64 kbps Opus stream.

A one-hour video that is 2 GB on disk becomes roughly 30 MB of audio. That happens on your machine, before anything is transmitted.

Supported video formats

• MP4 (H.264 / AAC) — the usual export from any camera or NLE.
• MOV (QuickTime) — including ProRes, as long as your browser can decode it.
• WEBM — screen recordings and web exports.

Extraction relies on the browser decoding the file. If a codec is not supported (some ProRes and HEVC variants), export a standard MP4 or a plain audio file first.

From transcript to SRT

Once the audio is transcribed and aligned, you choose how lines break — a fixed number of words, or natural sentence boundaries capped at a maximum length. You can split, join, and retype lines, and the timings stay correct because each word has its own timestamp.

Frequently asked questions

How long can the video be?

The limit is on extracted audio size, not duration: 25 MB. At the compression used that is roughly two hours of typical speech.

Does the video get uploaded?

No. Only the extracted audio is sent. The video file itself never leaves your machine.

Can I burn the subtitles into the video?

Not here — this produces subtitle files, not rendered video. Import the SRT or FCPXML into your editor and render there, which also keeps the captions editable.