MashLab is an automated, AI-driven audio mashup engine designed to seamlessly blend tracks using advanced Music Information Retrieval (MIR) techniques.

Audio Infrastructure: Utilizes PyTorch (Demucs) for 4-stem source separation and dynamic programming for onset cross-correlation and beat-grid snapping.

Compatibility Engine: Evaluates track pairings based on key (Krumhansl-Schmuckler), tempo, and spectral frequency separation.

Personalization: Implements an online logistic regression model that learns user preferences via SGD across 11 engineered audio features.

Repo layout:

• frontend/: React + Vite UI
• backend/: Python FastAPI mashup backend (from mashup_backend_v3)

• Node.js (for frontend)
• Python 3.10+ (backend tested with Python 3.14 without Demucs)
• FFmpeg on PATH (recommended for MP3 export)

From repo root:

npm.cmd run setup:frontend
npm.cmd run setup:backend

Create frontend/.env.local (copy from frontend/.env.example):

VITE_API_BASE_URL=http://localhost:8787

Terminal 1:

npm.cmd run dev:backend

Terminal 2:

npm.cmd run dev:frontend

Invoke-RestMethod http://localhost:8787/api/health

• No external API keys are required for this backend.
• Stem separation via Demucs is optional and currently excluded from default install because dependency support is limited on Python 3.14.