# Audio Transcription Pipeline

A modular audio transcription pipeline with speech recognition, audience response classification, speaker diarization, meeting summarization, and ASCII visualization.

## Architecture

```
Audio Input (WAV/FLAC/MP3)
    │
    ▼
┌────────────────────┐
│  Transcriber       │  ← faster-whisper (base model, CPU int8)
│  Word-level timing │     Language detection, beam search
└────────┬───────────┘
         │
         ▼
┌────────────────────┐
│  Audience Class.   │  ← Rule-based + AST (MIT/ast-finetuned-audioset)
│  10 event classes  │     Applause, laughter, cheering, music, etc.
└────────┬───────────┘
         │
         ▼
┌────────────────────┐
│  Diarizer          │  ← pyannote/speaker-diarization-3.1 or mock
│  Speaker labeling  │     HF_TOKEN required for full diarization
└────────┬───────────┘
         │
         ▼
┌────────────────────┐
│  Summarizer        │  ← Qwen2.5-0.5B-Instruct GGUF
│  Structured JSON   │     Overview, decisions, action items
└────────┬───────────┘
         │
         ▼
┌────────────────────┐
│  GlyphCast ASCII   │  ← Spectrogram → ASCII art
│  7 charsets/3 modes│     Dark, light, hallow themes
└────────────────────┘
```

## Quick Start

### CLI

```bash
cd /app/audio_transcription_pipeline_1527

# Full transcription
python main.py transcribe data/jfk_speech.wav --output json

# With summary + ASCII visualization
python main.py transcribe data/jfk_speech.wav --summary --ascii

# All pipeline modules at once
python main.py all data/jfk_speech.wav --output json

# Audience response classification only
python main.py audience data/test_tone.wav --output json

# ASCII visualization only
python main.py ascii-viz data/jfk_speech.wav --mode dark
```

### Web Demo (Runs as background service)

- **Frontend (Gradio)**: Port 8080
- **Backend API (FastAPI)**: Port 8081

```bash
# Start backend
python -m uvicorn api:app --host 0.0.0.0 --port 8081 --log-level warning

# Start frontend (in another terminal)
python app.py
```

### API Endpoints

| Endpoint | Method | Description |
|----------|--------|-------------|
| `/health` | GET | Health check |
| `/transcribe` | POST | Upload audio → transcription + analysis |

## Models Used

| Model | Source | Size | Purpose |
|-------|--------|------|---------|
| faster-whisper base | Systran/faster-whisper-base | ~150 MB | Speech recognition |
| AST audioset | MIT/ast-finetuned-audioset-10-10-0.4593 | ~230 MB | Audience classification |
| Qwen2.5-0.5B-Instruct | Qwen/Qwen2.5-0.5B-Instruct-GGUF | ~350 MB | Meeting summarization |
| Whisper-large-v3-turbo | openai/whisper-large-v3-turbo | ~2 GB | Encoder for hybrid model |
| Qwen3-8B-Instruct | Qwen/Qwen3-8B-GGUF | ~5 GB | LLM for hybrid model |

## Hybrid Speech-Transcription Model

See `hybrid_model/ARCHITECTURE.md` for details on the Encoder-Projector-LLM architecture.

## Requirements

- Python 3.10+
- CPU with ~8GB RAM minimum
- Optional: HuggingFace token for pyannote diarization

## License

MIT