subtune

A CLI tool for adjusting SRT subtitle timestamps with precision and safety.

Features

• Precise timing adjustment - Shift subtitles by milliseconds
• Safe operations - Optional backup creation before modifications
• Robust validation - Input validation with helpful error messages

Installation

Install from PyPI:

pip install subtune

Or install from source:

git clone https://github.com/rafa-garcia/subtune.git
cd subtune
pip install .

Usage

Basic Usage

# Shift subtitles 2 seconds later
subtune input.srt --offset 2000 output.srt

# Shift subtitles 1.5 seconds earlier  
subtune input.srt --offset -1500 output.srt

Advanced Options

# Modify in-place with backup
subtune input.srt --offset 1000 --backup

# Short flags
subtune input.srt -o 1000 -b

Command Reference

$ subtune --help
usage: subtune [-h] -o OFFSET [--output OUTPUT] [-b] [--version] input_file

Shift SRT subtitle timestamps by a specified offset

positional arguments:
  input_file            Input SRT file path

optional arguments:
  -h, --help            show this help message and exit
  -o OFFSET, --offset OFFSET
                        Time offset in milliseconds (positive=forward,
                        negative=backward)
  --output OUTPUT       Output file path (default: modify input file in-place)
  -b, --backup          Create backup of input file before modification
  --version             show program's version number and exit

Development

Quick Start

# Install development dependencies
pip install -e ".[dev]"

# Run all tests
pytest

# Verbose output with details
pytest -v

# Run specific test file
pytest tests/test_cli.py

# Run tests with coverage
pytest --cov=src/subtune

# Generate HTML coverage report
pytest --cov=src/subtune --cov-report=html
open htmlcov/index.html

# Check code quality
ruff check src/ tests/

License

MIT License - see LICENSE file for details.