Gemini SRT Translator Go

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Gemini SRT Translator Go - a powerful tool to translate subtitle files using Google Gemini AI.

Features

• 🔤 SRT Translation: Translate .srt subtitle files to a wide range of languages supported by Google Gemini AI
• ⏱️ Timing & Format: Maintains exact timestamps and basic SRT formatting of the original file
• 💾 Quick Resume: Easily resume interrupted translations from where you left off
• 🧠 Advanced AI: Leverages thinking and reasoning capabilities for more contextually accurate translations
• 🖥️ CLI Support: Full command-line interface for easy automation and scripting
• ⚙️ Customizable: Tune model parameters, adjust batch size, and access other advanced settings
• 📜 Description Support: Add description to guide AI in using specific terminology or context
• 📋 Interactive Features: Interactive model selection and automatic help display
• 📝 Logging: Optional saving of progress and thinking process logs for review

Installation

Prerequisites

• Go 1.23 or later

Build from Source

git clone https://github.com/luispater/gemini-srt-translator-go.git
cd gemini-srt-translator-go
go mod tidy
go build -o gst ./cmd

Configuration

Get Your API Key

1. Go to Google AI Studio
2. Sign in with your Google account
3. Click on Generate API Key
4. Copy and keep your key safe

Set Your API Key

Set the GEMINI_API_KEY environment variable with comma-separated keys for additional quota:

macOS/Linux:

export GEMINI_API_KEY="your_first_api_key_here,your_second_api_key_here"

Windows (Command Prompt):

set GEMINI_API_KEY=your_first_api_key_here,your_second_api_key_here

Windows (PowerShell):

$env:GEMINI_API_KEY="your_first_api_key_here,your_second_api_key_here"

Usage

Help and Usage

# Show help
./gst --help
# or simply run without arguments
./gst

Command Line Interface

Basic Translation

# Using environment variable (recommended)
export GEMINI_API_KEY="your_api_key_here"
./gst subtitle.srt -l "Simplified Chinese"

# Using command line argument with multiple keys
./gst subtitle.srt -l "Simplified Chinese" -k "YOUR_FIRST_API_KEY,YOUR_SECOND_API_KEY"

# Set output file name
./gst subtitle.srt -l "Simplified Chinese" -o translated_subtitle.srt

# Interactive model selection
./gst subtitle.srt -l "Brazilian Portuguese" --interactive

# Resume translation from a specific line
./gst subtitle.srt -l "Simplified Chinese" --start-line 20

# Suppress output
./gst subtitle.srt -l "Simplified Chinese" --quiet

Advanced Options

# Full-featured translation with custom settings
./gst input.srt \
  -l "Simplified Chinese" \
  -k YOUR_API_KEY \
  -o output_french.srt \
  --model gemini-2.5-pro \
  --batch-size 150 \
  --temperature 0.7 \
  --description "Medical TV series, use medical terminology" \
  --progress-log

Interactive Model Selection

Use interactive mode to see and select from available models:

./gst subtitle.srt -l "Simplified Chinese" --interactive

Configuration Options

Core Parameters

• GeminiAPIKeys: Array of Gemini API keys (parsed from comma-separated string)
• TargetLanguage: Target language for translation
• InputFile: Path to input SRT file
• OutputFile: Path to output translated SRT file
• StartLine: Line number to start translation from
• Description: Additional instructions for translation
• BatchSize: Number of subtitles to process in each batch

Model Parameters

• ModelName: Gemini model to use (default: "gemini-2.5-flash")
• Temperature: Controls randomness in output (0.0-2.0)
• TopP: Nucleus sampling parameter (0.0-1.0)
• TopK: Top-k sampling parameter (>=0)
• Streaming: Enable streamed responses (default: true)
• Thinking: Enable thinking capability (default: true)
• ThinkingBudget: Token budget for thinking process (0-24576)

User Options

• FreeQuota: Signal that you're using free quota (affects rate limiting)
• UseColors: Enable colored terminal output
• ProgressLog: Enable progress logging to file
• QuietMode: Suppress all output
• Resume: Automatically resume interrupted translations

Project Structure

gemini-srt-translator-go/
├── cmd/                  # Command-line interface
│   └── main.go
├── internal/             # Internal packages
│   ├── translator/       # Core translation logic
│   ├── logger/           # Logging and progress display
│   └── helpers/          # Gemini API helpers
├── pkg/                  # Public packages
│   ├── config/           # Configuration management
│   ├── errors/           # Error handling
│   └── srt/              # SRT parsing and formatting
└── test/                 # Test files

Main Dependencies

• github.com/spf13/cobra: CLI framework
• google.golang.org/genai: Official Gemini AI client
• golang.org/x/term: Terminal password input

Testing

Run the test suite:

go test ./...

Run tests with coverage:

go test -cover ./...

Development

Building

go build -o gst ./cmd

Cross-compilation

# Windows
GOOS=windows GOARCH=amd64 go build -o gst.exe ./cmd

# macOS
GOOS=darwin GOARCH=amd64 go build -o gst-macos ./cmd

# Linux
GOOS=linux GOARCH=amd64 go build -o gst-linux ./cmd

Features Explained

Translation Workflow

1. Input Validation: Check files, API keys, and parameters
2. Model Validation: Verify selected Gemini model availability
3. Token Management: Get model token limits and validate batch sizes
4. Batch Translation: Process subtitles in configurable batches
5. Progress Tracking: Save progress for resumable translations
6. Output Generation: Write translated SRT with proper formatting

Error Handling

• API errors trigger key rotation when multiple keys available
• File validation occurs before processing begins
• Progress is saved after each successful batch
• Cleanup of temporary files on completion

Multi-API Key Support

• Supports rotation through multiple API keys
• Automatic handling of quota limits and error recovery
• Enhanced processing capability for free quota users

License

Distributed under the MIT License. See the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Support

If you encounter any issues or have questions, please check the documentation or create an issue in the repository.