YASTwAI

Yet Another Subtitle translator with AI

About • Features • Installation • Quick Start • Configuration • Contributing • License

About

YASTwAI is a command-line tool that extracts subtitles from videos and translates them using AI. Whether you're watching foreign films, studying languages, or preparing content for international audiences, YASTwAI makes subtitle translation simple and effective.

Built with Rust for performance and reliability, YASTwAI supports multiple AI translation providers and preserves the original subtitle formatting and timing.

Key Features

• 🎯 Extract & Translate - Pull subtitles from videos and translate in one step
• 🌐 Multiple AI Providers - Support for Ollama, OpenAI, Anthropic
• ⚡ Concurrent Processing - Efficient batch translation for faster results
• 🧠 Smart Processing - Preserves formatting and timing of your subtitles
• 🔄 Direct Translation - Translate existing SRT files without needing video
• 📊 Progress Tracking - See real-time progress for lengthy translations

Installation

Prerequisites

• Rust and Cargo (1.85.0 or newer)

  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

• FFmpeg installed on your system (for subtitle extraction)

  # On Ubuntu/Debian
  sudo apt install ffmpeg
  
  # On macOS with Homebrew
  brew install ffmpeg
  
  # On Windows with Chocolatey
  choco install ffmpeg

• GitHub CLI (gh) for pull request operations

  # On Ubuntu/Debian
  sudo apt install gh
  
  # On macOS with Homebrew
  brew install gh
  
  # On Windows with Chocolatey
  choco install gh

Build from Source

# Clone the repository
git clone https://github.com/nstefan/yastwai.git
cd yastwai

# Build the application
cargo build --release

# The executable will be in target/release/yastwai

Quick Start

1. Copy the example config (or let YASTwAI create one for you):

   cp conf.example.json conf.json

2. Run YASTwAI:

   # Translate subtitles from a video file
   ./target/release/yastwai video.mkv
   
   # Process an entire directory
   ./target/release/yastwai videos/
   
   # Translate an SRT file directly
   ./target/release/yastwai subtitles.srt
   
   # Force overwrite existing translations
   ./target/release/yastwai -f video.mkv

3. Find your translations next to the original files as original_name.{target_language}.srt

Configuration

YASTwAI uses a JSON configuration file with these settings:

{
  "source_language": "en",
  "target_language": "fr",
  "translation": {
    "provider": "ollama",
    "available_providers": [
      {
        "type": "ollama",
        "model": "mixtral:8x7b",
        "endpoint": "http://localhost:11434",
        "concurrent_requests": 2,
        "max_chars_per_request": 1000,
        "timeout_secs": 60
      },
      {
        "type": "openai",
        "model": "gpt-4o-mini",
        "api_key": "your_api_key",
        "endpoint": "https://api.openai.com/v1",
        "concurrent_requests": 10,
        "max_chars_per_request": 2000,
        "timeout_secs": 60
      },
      {
        "type": "anthropic",
        "model": "claude-3-haiku-20240307",
        "api_key": "your_api_key",
        "endpoint": "https://api.anthropic.com",
        "concurrent_requests": 2,
        "max_chars_per_request": 400,
        "timeout_secs": 60,
        "rate_limit": 45
      }
    ],
    "common": {
      "system_prompt": "You are an expert subtitle translator specializing in {source_language} to {target_language} translation. Your task is to translate subtitle text PRECISELY while following these CRITICAL RULES:\n\n1. TRANSLATE EVERY SINGLE SUBTITLE - never skip any line or leave anything untranslated.\n2. PRESERVE EXACT FORMATTING - keep ALL special tags (like \{\\an8}), line breaks, and punctuation in the EXACT SAME POSITION as the original.\n3. MAINTAIN EXACT NUMBER OF LINES - your output MUST have the SAME number of lines as the input.\n4. PRESERVE TIMING CONSIDERATIONS - keep translations concise enough to be read in the same timeframe.\n5. PRESERVE MEANING AND CONTEXT - capture cultural nuances accurately.\n6. MAINTAIN TONE AND REGISTER - preserve formality level, slang, humor, and emotional tone.\n7. KEEP SPECIAL CHARACTERS INTACT - never modify or remove format codes like \{\\an8} or any other technical markers.\n8. RESPECT SUBTITLE LENGTH - translations should ideally be similar in length to maintain readability.\n\nFor each subtitle I send you, you MUST return a complete translation. Missing translations are NOT acceptable under any circumstances.",
      "rate_limit_delay_ms": 3000,
      "retry_count": 3,
      "retry_backoff_ms": 3000,
      "temperature": 0.3
    }
  },
  "log_level": "info",
  "batch_size": 1000
}

Translation Providers

Ollama (Default, Local)

• 🏠 Free, runs locally on your machine
• 🔗 Install from ollama.ai
• 🧩 Pull your model: ollama pull mixtral:8x7b

OpenAI

• 🔑 Requires API key from platform.openai.com
• 🧠 Models: gpt-4o-mini, gpt-4o, etc.

Anthropic

• 🔑 Requires API key from anthropic.com
• 🧠 Models: claude-3-haiku, claude-3-sonnet, etc.

See the example configuration file for more detailed options.

Contributing

Contributions are welcome! If you have a suggestion that would make this better, please fork the repo and create a pull request. You can also open an issue with the tag "enhancement".

Several helper scripts are available in the scripts/ directory to assist contributors:

• ai-commit.sh - Create well-structured commit messages
• ai-update-main.sh - Safely update the main branch without interactive prompts
• ai-pr.sh - Generate formatted pull requests
• ai-clippy.sh - Run Rust code linting

Don't forget to give the project a star! Thanks!

License

Distributed under the MIT License. See LICENSE for more information.

Acknowledgments

• Cursor Editor for making AI-powered development possible
• FFmpeg for the powerful media processing capabilities