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OpenSubs: I built a subtitle generator that runs Whisper in the browser, so the video never gets uploaded (opensubs.app)

submitted 2 days ago by opensubs@lemmy.world to c/opensource@lemmy.ml

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I work on OpenSubs, a free, open source (AGPL-3.0) subtitle tool that runs entirely in the browser tab.

You drop in a video file, and Whisper transcribes it on your own machine, using transformers.js with WebGPU where available and WebAssembly otherwise. The model (40–250 MB) downloads once and is cached. There is no upload endpoint in the product, so the video has nowhere to go.

After that you can:

fix lines by typing over them (click a timestamp to jump to that moment)
translate into 20 languages with Chrome's built-in on-device translator
pick one of 12 caption styles, including word-by-word highlighting
export SRT / VTT / ASS, or burn the subtitles into an MP4 (libass compiled to WebAssembly, encoded with WebCodecs)

A few things I learned building it:

Whisper hallucinates on silence and music ("Thanks for watching!", or the Japanese equivalent). A Silero VAD pass runs before Whisper, and a cleanup step drops the known stock phrases.
Singing doesn't count as speech for the VAD, so a music video gets a "no speech found" warning. You can still force it.

Honest limits: it only takes video files, not audio-only files. Cue timings can't be edited yet. Builds are release candidates. Everything that runs locally is free with no account; the only paid part is optional cloud translation on our backend (US$5 for 1000 credits), and you can bring your own Claude / OpenAI / DeepL key instead.

Site: https://opensubs.app/ Code: https://github.com/open-subs/opensubs

Feedback welcome, especially on languages where the transcription goes wrong.

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[-] fegular@lemmy.zip 1 points 19 hours ago

while abandoning it after 2 months. This hurts the open source community imho.

I dont expect them to maintain it for eternity. The problem is people expect too much from the authors as if it's the author's duty to fix bugs and add features. And tbh, this attitude hurts open source community more than anything. Ffs, the code is open source, do what you like. The author is not responsible for everything. Be grateful that the code is open-source.

[-] antianarchist@sopuli.xyz 2 points 19 hours ago

I am not talking about the many projects, where you have a single developer just enjoying making software, while providing it to the open source community. I have zero expectations to those projects.

I am talking about people promoting their open source products. Making a fancy website. Act professionally. All this behavior causes people to have expectations. So why invest time into promoting it in the first place? There is literally no need to do this, expect for the owner to attract more and more people.

Don’t promise a sky scraper if you can only maintain a bungalow.