🎥 Video Duration Calculator

Fast, privacy-first video duration calculation using a custom MP4 binary parser, browser metadata, and an optional AI fallback.

Fast • Browser-Based • Privacy First • Open Source

Features • Preview • How it Works • Installation • Privacy

---

📸 Preview

---

✨ Features

Feature	Description
⚡ Fast MP4 Binary Parser	Reads MP4 metadata directly without decoding the video.
📁 Batch Processing	Process multiple videos with drag & drop support.
🎬 Multi-stage Detection	Binary parser → Browser Metadata → AI Fallback.
📊 Duration Statistics	Calculate total and average duration instantly.
🤖 Optional AI Fallback	Uses Gemini only when local detection fails.
🔒 Privacy First	Files remain on your device whenever possible.
💻 Browser Based	No installation required.

---

Why?

Most online video duration calculators require uploading videos to a server.

This project processes videos locally whenever possible using a custom MP4 binary parser.

This makes duration detection significantly faster while keeping your videos private.

---

🚀 How it Works

The application follows a three-stage detection pipeline.

       [ Upload Video Files ]
                 │
                 ▼
    ┌─────────────────────────┐
    │  1. Binary MP4 Parser   │ ──(Success)──► [ Display Results ✅ ]
    └─────────────────────────┘
                 │
             (Failed)
                 │
                 ▼
    ┌─────────────────────────┐
    │ 2. HTML5 Metadata API   │ ──(Success)──► [ Display Results ✅ ]
    └─────────────────────────┘
                 │
             (Failed)
                 │
                 ▼
    ┌─────────────────────────┐
    │ 3. Gemini AI Fallback   │ ──(Success)──► [ Display Results ✅ ]
    └─────────────────────────┘

The majority of MP4 files are processed locally using the custom binary parser, making the application extremely fast while keeping videos on your device.

---

🛠 Technology Stack

Category	Technologies
Frontend	React
Language	TypeScript
Build Tool	Vite
Local Processing	HTML5 Video API
Binary Parsing	Custom MP4 Parser
AI (Optional)	Google Gemini

---

📂 Project Structure

src/
│
├── components/
│
├── utils/
│   ├── mp4Parser.ts
│   ├── videoProcessor.ts
│   └── timeFormatter.ts
│
├── types.ts
├── App.tsx
└── main.tsx

---

📦 Installation

Clone the repository

git clone https://github.com/lab1207/Video-Duration-Calculator.git

Enter the project

cd Video-Duration-Calculator

Install dependencies

npm install

Create a .env file

GEMINI_API_KEY=YOUR_GEMINI_API_KEY

Get your free API key from Google AI Studio:

https://aistudio.google.com/app/apikey

Run the development server

npm run dev

Build for production

npm run build

Preview production build

npm run preview

---

🔑 Environment Variables

Variable	Required	Description
GEMINI_API_KEY	Optional	Enables the AI fallback used only when local video duration detection fails.

---

🔒 Privacy

This application is designed to process videos locally whenever possible.

Processing order:

1. Custom MP4 Binary Parser
2. Browser Metadata
3. Google Gemini AI (Optional)

If you do not provide a GEMINI_API_KEY, the application will continue working normally for supported video formats. Only the optional AI fallback will be unavailable.

---

🌍 Browser Support

• ✅ Chrome
• ✅ Edge
• ✅ Firefox
• ✅ Safari

---

🗺 Roadmap

• Folder Upload
• Recursive Directory Scanning
• Parallel Processing Queue
• CSV Export
• Excel Export
• JSON Export
• Additional Video Format Support
• Progress Indicators
• Offline Mode (PWA)
• File Search & Filtering

---

🤝 Contributing

Contributions, issues, and feature requests are welcome.

Feel free to open an issue or submit a pull request.

---

📄 License

This project is licensed under the MIT License.