AudioLevel

Professional Audio Normalization for Everyone

A free, web-based audio normalization tool. Upload your audio, pick a preset, and download broadcast-ready files. No login required. No data retained.

Features

• 6 Industry Presets — Podcast, Broadcast, YouTube, Streaming, Mastering, Audiobook
• Multi-Format Support — WAV, MP3, FLAC, AAC, OGG input and output
• Real-Time Progress — WebSocket-powered live updates during processing
• Privacy First — All files auto-delete after 15 minutes
• No Account Needed — Just upload and go
• Download History — Session-based tracking of recent conversions

Quick Start

Using Docker (Recommended)

# Clone the repository
git clone https://github.com/miikkis-gh/audiolevel.git
cd audiolevel

# Start all services
docker compose up -d

# Open in browser
open http://localhost:80

Manual Setup

# Prerequisites: Bun, Redis, FFmpeg, ffmpeg-normalize

# Backend
cd backend
bun install
bun run dev

# Frontend (new terminal)
cd frontend
bun install
bun run dev

Visit http://localhost:5173 for the frontend.

Presets

Architecture

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   Browser   │────▶│   Frontend  │────▶│   Backend   │
│             │◀────│   (Svelte)  │◀────│   (Hono)    │
└─────────────┘     └─────────────┘     └──────┬──────┘
                           │                   │
                           │ WebSocket         │ Jobs
                           ▼                   ▼
                    ┌─────────────┐     ┌─────────────┐
                    │   Nginx     │     │   BullMQ    │
                    │  (optional) │     │   + Redis   │
                    └─────────────┘     └──────┬──────┘
                                               │
                                               ▼
                                        ┌─────────────┐
                                        │   FFmpeg    │
                                        │  Normalize  │
                                        └─────────────┘

Tech Stack

Backend

• Bun — Runtime
• Hono — Web framework
• BullMQ — Job queue
• Redis — State & queue backend
• FFmpeg + ffmpeg-normalize — Audio processing

Frontend

• Svelte 5 — UI framework with runes
• Vite 7 — Build tool
• Tailwind CSS 4 — CSS-first styling

API

Endpoints

POST   /api/upload              Upload audio file
GET    /api/upload/job/:id      Get job status
GET    /api/upload/job/:id/download  Download processed file
GET    /api/presets             List available presets
GET    /api/health              Health check
WS     /ws                      Real-time progress updates

WebSocket Events

// Subscribe to job updates
ws.send(JSON.stringify({ type: 'subscribe', jobId: 'abc123' }))

// Receive progress
{ type: 'progress', jobId: 'abc123', percent: 45, stage: 'normalizing' }

// Receive completion
{ type: 'complete', jobId: 'abc123', downloadUrl: '/api/upload/job/abc123/download' }

Full API documentation: docs/API.md

Configuration

Environment Variables

# Backend
PORT=3000
REDIS_URL=redis://localhost:6379
UPLOAD_DIR=./uploads
OUTPUT_DIR=./outputs
MAX_FILE_SIZE=104857600          # 100MB
FILE_RETENTION_MINUTES=15
MAX_CONCURRENT_JOBS=4
PROCESSING_TIMEOUT_MS=300000     # 5 minutes

# Frontend
VITE_API_URL=http://localhost:3000
VITE_WS_URL=ws://localhost:3000/ws

Reverse Proxy Configuration

This application runs behind an nginx reverse proxy that handles SSL termination.

Host nginx configuration:

• Handles SSL/TLS (HTTPS on port 443)
• Proxies requests to http://localhost:8081
• Manages Let's Encrypt certificates

Docker nginx configuration:

• Serves HTTP only on port 80 (mapped to host port 8081)
• No SSL configuration needed
• No HTTPS redirects

Production Deployment

# Using production compose file
docker compose -f docker-compose.prod.yml up -d

Deployment guide: docs/DEPLOYMENT.md

Development

# Run tests
cd backend && bun test
cd frontend && bun test

# Type checking
cd backend && bun run typecheck
cd frontend && bun run check

# Build for production
cd frontend && bun run build

Project Structure

audiolevel/
├── backend/
│   ├── src/
│   │   ├── index.ts         # Server entry
│   │   ├── routes/          # API handlers
│   │   ├── services/        # Business logic
│   │   ├── workers/         # Job processors
│   │   └── websocket/       # Real-time handlers
│   └── package.json
├── frontend/
│   ├── src/
│   │   ├── App.svelte       # Main component
│   │   ├── app.css          # Tailwind CSS 4 theme
│   │   ├── lib/components/
│   │   │   ├── audiolevel/  # Audio processing UI
│   │   │   │   ├── AudioLevelUI.svelte
│   │   │   │   ├── ParticleSphere.svelte
│   │   │   │   ├── BatchReport.svelte
│   │   │   │   ├── SingleReport.svelte
│   │   │   │   └── OverrideSelector.svelte
│   │   │   └── ...          # Other components
│   │   └── stores/          # State management
│   └── package.json
├── docs/                    # Documentation
├── nginx/                   # Nginx config
└── docker-compose.yml

Limits

Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing)
5. Open a Pull Request

License

MIT License — see LICENSE for details.

_{Built with FFmpeg, Bun, and a love for good audio.}