A free SRT file generator that runs in your browser
OpenSubs (opensubs.app) is an SRT file generator: drop in a video and it writes an .srt from the speech, every line timed to the audio. Whisper runs in this tab, so the video is not uploaded. Free, with no account and no watermark, and open source.
Free. No account, no watermark. MP4, MOV, WebM and MKV.
How to create an SRT file from a video
The SRT file generator is the same tool as the subtitle generator on the home page. Here is the short path from an MP4 to SRT.
- Open opensubs.app and choose a video, or drop it anywhere on the page.
- Pick the spoken language, or leave it on automatic. The first time, the speech model downloads once, between 40 MB and 250 MB, and is cached after that.
- Read through the lines. Fix a name or a misheard word by typing over it.
- Open the Export tab and press .srt. The file takes the video's name, so
talk.mp4gives youtalk.srt.
What the SRT file generator writes
An SRT file is plain text: a number, a start and end time, and the words, then a blank line before the next one. Players, editors and video platforms all read it. This is what comes out:
1
00:00:01,200 --> 00:00:04,050
Thanks for joining. Today we start with the basics.
2
00:00:04,300 --> 00:00:07,900
If you have questions, keep them for the end.Timed to the speech
Each line's start and end come from the audio, so you get an SRT file you can hand straight to a player or an editor.
Two languages in one video
On automatic, the language is read from the audio every four seconds, so a video that switches between two languages is transcribed in both and comes out as one SRT file.
Other formats too
The same Export tab saves .vtt, .ass with the style you chose, and .txt with just the words and no timings.
Or in the picture
If you would rather not ship an SRT file at all, burn the subtitles into the video and export an MP4.
MP4 to SRT without uploading the video
This SRT file generator does not send the video to a server. It fetches only the speech model; the audio is read in the browser, on the GPU where your machine has one. A long video on a laptop with built-in graphics takes a while, and it is still free.
Before you save, you can correct the text in the subtitle editor, or translate the subtitles into another language and save that as SRT instead.
What it will not do
- Write an SRT by hand from nothing. This SRT file generator makes the lines from what is said in the video.
- Change timings. You can rewrite what a line says, but not when it starts or how long it stays, and lines cannot be added, deleted or merged.
- Start from an audio file. The web app takes a video.
What leaves your machine
With the default settings, only the speech model is downloaded; the video stays put. You can check it: open the Network tab, then generate an SRT file. The audio is never in a request.
The source is public under the AGPL-3.0-or-later, on GitHub. Questions, or a problem to report: email hello@opensubs.app.
Questions
How do I create an SRT file from my video for free?
Open opensubs.app, choose the video, let it transcribe, then press .srt in the Export tab. The SRT file generator is free, with no account and no watermark.
Is my video uploaded?
No. Whisper runs in your browser. Only the speech model is downloaded, once.
Can I turn an MP4 into an SRT?
Yes. MP4, MOV, WebM and MKV all work. The SRT file is named after the video.
Can I edit the lines before I save?
Yes, the words. Each line is a text box. The timings stay as they were generated.
I already have a .vtt. Do I need this?
No. Open it and save it as SRT: VTT to SRT.