Subtitle Toolkit 🍿

Swiss Army knife for everything subtitle-related.

Subtitle Toolkit is a collection of tools for working with subtitle files. Whether you're a translator, video editor, accessibility advocate, or just someone who needs to fix out-of-sync subtitles, this toolkit has you covered.

What Can It Do?

• Translate subtitles using AI (supports any LLM via LiteLLM)
• Fix timing with uniform shifts or drift correction for frame-rate issues
• Convert between formats: SRT, VTT, ASS, TTML, and many more
• Extract subtitle tracks from MKV/MP4 video files
• Merge multiple subtitle tracks into one

Installation

For end users:

pip install subtitle-toolkit

For the web interface:

pip install subtitle-toolkit[web]

For developers (all dependencies including testing tools):

pip install subtitle-toolkit[all]

Or install in editable mode for development:

pip install -e subtitle-toolkit[all]

Quick Start

Web interface (recommended for most users):

subtitle-tk web
# Then open http://localhost:8000 in your browser

Command line:

# Shift every timestamp 2.5 seconds later (positive = later)
subtitle-tk timeshift --shift-seconds 2.5 < input.srt > output.srt

Web Interface

The web interface is the easiest way to use Subtitle Toolkit. No command line needed—just upload your file, adjust settings, and download the result.

Getting Started

1. Start the server:

   subtitle-tk web
   

2. Open your browser to http://localhost:8000

3. Choose a tool from the menu and follow the on-screen instructions

Available Tools

Multi-Language Support

The web interface is available in 17 languages: English, Arabic, German, Spanish, Persian, French, Indonesian, Italian, Japanese, Korean, Dutch, Polish, Portuguese, Turkish, Ukrainian, Vietnamese, and Chinese.

Command-Line Interface

For scripting, automation, or if you prefer the terminal, the CLI provides the same functionality.

Commands

Examples

Translate subtitles (requires API key or local LLM):

subtitle-tk translate input.srt --instructions "Translate to Spanish"

Shift timestamps (move subtitles to 3 seconds later):

subtitle-tk timeshift --shift-seconds 3 < input.srt > output.srt

Fix drift (at 10:00, subtitles are 5 seconds late):

subtitle-tk autosync --correct-at 00:00:00 --offset-at 00:10:00 --offset 5 < input.srt > output.srt

Or specify multiple sync points:

subtitle-tk autosync --point 00:00:00:0 00:05:00:2.5 00:10:00:5 < input.srt > output.srt

List subtitle tracks in a video:

subtitle-tk subtitle-tracks list video.mkv

Extract all subtitle tracks as a zip file:

subtitle-tk subtitle-tracks extract video.mkv --all --as-zip

Convert to VTT format:

subtitle-tk convert input.srt --output-format vtt -o output.vtt

Get help for any command:

subtitle-tk <command> --help

Common Use Cases

"My subtitles are 2 seconds late"

Use Timeshift with a positive shift value.

"My subtitles start fine but drift out of sync over time"

Use Autosync with one or more sync points.

"I need subtitles in another language"

Use Translate with your preferred AI provider.

"I have a video file and need the subtitle tracks"

Use Subtitle Tracks to extract them.

"My video editor needs a different subtitle format"

Use Convert to change the format.

Docker (Optional)

Skip this section if Docker isn't your thing. The pip installation works great for most users.

docker build -t subtitle-toolkit .
docker run -p 8000:8000 subtitle-toolkit

Contributing

Contributions are welcome! Feel free to open issues or submit pull requests. The codebase is Python 3.8+ and uses FastAPI for the web interface.

License

GPL-3.0 — See LICENSE for details.

Happy subtitling! 🎬