# TTS — Audio Generation for ASFR Stories

## What

Generates audiobooks from story files using **Silero TTS v5** (Russian). Two voices:
- **Narrator** — male voice (`eugene`) for the story prose
- **Cyborg voice** — same voice with robotic effect (pitch shift + ring modulation + bitcrush) for system error messages (`ОШИБКА:`, `ПРЕДУПРЕЖДЕНИЕ:`)

## Setup

```bash
uv add torch torchaudio silero silero-stress soundfile librosa
```

## Usage

```bash
# Generate Silas audiobook
uv run tts/tts_silas.py Silas.md

# Generate any story
uv run tts/tts_silas.py Logan.md
```

Output goes to `tts/output/`:
- `<name>_full.wav` — complete audiobook
- `<name>_demo.wav` — first 4 segments (~1 min)

## Voice Options

Available Silero v5_ru voices:
- `aidar` — deep male (can be monotone)
- `eugene` — male, more expressive intonation ← default
- `baya` — female, soft
- `kseniya` — female, clear
- `xenia` — female, calm

Change `SPEAKER` in `tts_silas.py` to switch voices.

## Robotic Effect

System messages get these audio effects:
- Pitch shift: -4 semitones (deeper, more mechanical)
- Ring modulation: 50 Hz carrier (metallic timbre)
- Bitcrush: 200 levels (digital distortion)

Parameters in `make_robotic()` can be tuned.

## Known Issues

- Silero can misplace Russian word stress on complex sentences
- Long paragraphs are split at sentence boundaries
- Robotic effect uses librosa which has deprecation warnings (harmless)