LastFrame

Overview

LastFrame is a lightweight command-line tool that extracts the first frame from MP4 video files using OpenCV (cv2).

It automatically scans the current directory for .mp4 files (case-insensitive), displays an interactive numbered list with file sizes, lets the user select a video, and saves the first frame as an image file (PNG by default; supports JPG, JPEG, BMP, TIFF).

The tool features clear prompts, basic error handling, and a pause at the end — perfect for quick thumbnail generation, cover image creation, or inspecting video starts without loading the entire file.

Features

• Finds all .mp4 / .MP4 / .Mp4 files in the current folder using glob
• Shows numbered list with file sizes (in MB) for easy selection
• Extracts the very first frame reliably with a single cap.read() call
• Smart default output filename: output.png (if free) or {video_name}_first.png
• Automatically adds .png extension if user input lacks an image suffix
• Clean resource handling (cap.release()) — no temporary files
• User-friendly success/error messages and final confirmation

Prerequisites

• Python 3.8+ (recommended: 3.10–3.12)
• opencv-python (installed via pip)
• Optional: virtual environment (venv or uv)

No C compiler or Cython is required for normal usage — the project is currently pure Python.

Installation

Development / Source Install (Editable)

# 1. Clone or download the repo
git clone <your-repo-url>
cd LastFrame

# 2. (Recommended) Create & activate virtual environment
python3 -m venv venv
source venv/bin/activate    # Windows: venv\Scripts\activate

# 3. Install dependencies
pip install opencv-python
# If you later add ChronicleLogger or others → add them here

# 4. Install project in editable mode
pip install -e .

Now you can run it with:

python -m LastFrame

Future PyPI Release (when ready)

pip install lastframe

(You would then publish it via python -m build + twine, and configure console_scripts in pyproject.toml for a lastframe command.)

Usage

Place your MP4 videos in the current directory and run:

python -m LastFrame

Example session:

Found MP4 videos:

  1. intro.mp4   (12.4 MB)
  2. demo.MP4    (45.8 MB)

Enter video number (1-2): 1

Selected: intro.mp4
Enter output image filename [default: output.png]: 

Extracting first frame from 'intro.mp4'...
Success: First frame saved as 'output.png'

Done! Image saved as: output.png

Press Enter to exit...

Or specify a custom name:

Enter output image filename [default: intro_first.png]: cover.jpg

The tool saves the image and waits for you to press Enter before closing.

For scripting / automation:

from LastFrame.__main__ import main
main()

Project Structure

Follows modern Python packaging conventions with src/ layout:

LastFrame/
├── README.md
├── pyproject.toml            # (add when packaging properly)
├── src/
│   └── LastFrame/
│       ├── __init__.py
│       └── __main__.py       # Main logic + entry point
└── (optional future folders)
    ├── tests/
    └── docs/

Development Notes

• The core logic lives in src/LastFrame/__main__.py
• To add features (batch mode, other formats, progress bar…): edit the main() and get_first_frame() functions
• Logging: ChronicleLogger is imported but unused — either integrate it or remove the import
• Tests: Consider adding tests/ folder + pytest later
• Packaging: When ready, add pyproject.toml with build-system = {requires = ["hatchling"], build-backend = "hatchling.build"} (or setuptools)

Troubleshooting

• Cannot open video → Check file path, integrity, and codec support in your OpenCV build
• No MP4 files found → Make sure videos are in the current working directory (pwd)
• OpenCV not found → pip install opencv-python
• Permission denied on save → Check write permissions in current folder

License

MIT License
(Add a LICENSE file with the standard MIT text when you publish or share the repo.)