Migrating from Spotify Audio Features: a Field-by-Field Threshold Guide

TL;DR: Spotify killed /audio-features on 2024-11-27. FreqBlog Music API offers a drop-in at api.freqblog.com/v1/audio-features/{id} — same path, same response shape. The numbers are ours (signal analysis via librosa + Essentia, not Spotifys ML classifiers), so a few field distributions shift. This is the field-by-field guide to re-tuning, with real distribution data from our ~57,000-track catalog. This is a syndicated mirror — the canonical version with full formatting is at https://freqblog.com