OfflineSubs

Offline subtitle generator

Generate subtitles with no internet connection. The model downloads once, is cached by your browser, and after that the tool works fully offline.

Drop your video or audio file here
or click to choose · mp4 mov webm mp3 wav m4a ogg flac

How an offline tool is possible

Speech recognition normally implies a server. But a small quantised model — about 75 MB — runs fine as WebAssembly inside a browser, and once downloaded it is cached like any other web asset.

So the first visit needs a connection; every visit after that does not. This is genuinely useful on planes, on set, in a locked-down corporate network, or anywhere you would rather not rely on a connection while handling footage.

Browsers may clear cached data under storage pressure, which would require re-downloading the model. Keeping the tab or using the site regularly lowers the chance of that happening.

FAQ

Does it really work with the internet switched off?

Yes, once the model has been cached. Try it: load the page, then disconnect and run a file.

How much is downloaded the first time?

About 75 MB — the speech model. Nothing else is fetched, and it is cached locally afterwards.

Will the cache ever be cleared?

Possibly. Browsers can evict cached data when disk space runs low. If that happens the model simply downloads again.

Is my media uploaded during that first download?

No. The two things are separate: only the model is fetched, and it is fetched from a public model host.