Fast Sub Help
User documentation
Create, translate, and burn subtitles locally.
Fast Sub is a local-first subtitle generation and translation tool for video and audio files. This help site is written for normal product usage; developer contracts and generated API references live in the project development docs.
Windows x64
Release-candidate installer and portable zip.
macOS arm64
Preview dmg; ad-hoc signed and not notarized.
Models
Installed on first run; not bundled with the app.
Start Here
Getting started
Understand the main workflow and first successful run.
Download Fast Sub
Check platform status, release limits, and artifact notes.
Install on Windows
Install the release-candidate build and launch the app.
First run and models
Prepare local transcription and translation models.
Generate subtitles
Create original-language subtitles from media files.
Common Tasks
Translate subtitles
Translate SRT files or text with explicit provider selection.
Create bilingual subtitles
Combine source and translated captions.
Burn subtitles into video
Render subtitles into a media file.
Configure providers
Review local, web, and API provider behavior.