> ## Documentation Index
> Fetch the complete documentation index at: https://docs.medera.info/llms.txt
> Use this file to discover all available pages before exploring further.

# Spectral Features

> MFCC, centroid, bandwidth, rolloff, flatness

Computed by `_extract_spectral_features(audio)` using audio analysis library. | Feature | Unit |
\| :--- | :--- |
\| `mfcc` | 13 coefficients (list) |
\| `spectral_centroid` | Hz |
\| `spectral_bandwidth` | Hz |
\| `spectral_rolloff` | Hz |
\| `spectral_flatness` | 0–1 (tonal ↔ noise-like) |
\| `spectral_confidence` | 0–1 | MFCCs power downstream classifiers (emotion, depression risk) and are also passed into the neurobehavioral fusion as feature contributions.