🎸 ChordSnap

ChordSnap is a Python-based web app that analyzes uploaded audio files (.mp3/.wav) and detects chords over time, featuring simple visualizations and instrument-specific presentation. 🎵

🛠️ Stack

• Backend: FastAPI (Python) 🐍 with chroma-based chord detection (librosa) 🎼
• Frontend: Vite ⚡ + React ⚛️ + TypeScript 📘

🚀 Quick Start

🔗 Live Demo

[https://chord-snap.vercel.app/]

1️⃣ Backend Setup

⚠️ Important: For MP3/MP4 file support, you may need FFmpeg installed:

• Windows: Download from ffmpeg.org or use winget install ffmpeg
• Mac: brew install ffmpeg
• Linux: sudo apt install ffmpeg or sudo yum install ffmpeg

cd backend
python -m venv .venv
. .venv/Scripts/activate
pip install -r requirements.txt
uvicorn app.main:app --reload --port 8000

Note: If you encounter "Unspecified internal error" when uploading MP3/MP4 files, install FFmpeg or convert your files to WAV format.

2️⃣ Frontend Setup

The frontend is located in the project root.

npm install
npm run dev

Open the frontend dev server URL shown in the console (e.g., http://localhost:5173). Ensure the backend is running on http://localhost:8000 or update VITE_API_BASE_URL in .env accordingly.

✨ Features

• 📤 Upload .mp3 or .wav files
• 🎸 Instrument Selection (Guitar, Piano, Ukulele)
• ⏱️ Chord Timeline with precise timestamps
• 🎧 Playback audio alongside detected chords

📝 Notes

• Chord Detection: Uses chroma features and template matching for major/minor triads. Lightweight and CPU-friendly. 🧠
• Accuracy: Depends on audio quality, tuning, and arrangement. Future improvements may include key estimation, seventh chords, and HMM smoothing. 🔮

🔌 Backend API

• POST /analyze (multipart/form-data):
  • file: Audio file 📁
  • instrument: Optional instrument type 🎻
  • Returns: { segments: [{ startSec, endSec, chord, confidence }], durationSec }