# src/features
## Purpose
Filterbank (FBank) feature extraction and CMVN normalization for speaker
embedding pipelines.
## Surfaces
- `FbankConfig` — configuration
- `FbankExtractor` — mel-filterbank extractor
- `apply_cmvn` — cepstral mean and variance normalization
## Dependencies
- `realfft`, `rustfft` — FFT for spectrogram computation
## Invariants
- FbankExtractor outputs non-negative mel energies before CMVN.
## Verification
```bash
cargo test --lib features
```
## Notes
- Default configuration targets 16kHz audio.