# TTS Options Research for Daily Digest Podcast

## Executive Summary
After evaluating multiple TTS solutions, **Piper TTS** emerges as the best choice for a daily digest workflow, offering excellent quality at zero cost with full local control.

---

## Option Comparison

### 1. **Piper TTS** ⭐ RECOMMENDED
- **Cost**: FREE (open source)
- **Quality**: ⭐⭐⭐⭐ Very good (neural voices, natural sounding)
- **Setup**: Easy-Medium (binary download + voice model)
- **Platform**: macOS, Linux, Windows
- **Automation**: CLI tool, easily scripted
- **Pros**: 
  - Completely free, no API limits
  - Runs locally (privacy, no internet needed)
  - Fast inference on CPU
  - Multiple high-quality voices available
  - Active development (GitHub: rhasspy/piper)
- **Cons**: 
  - Requires downloading voice models (~50-100MB each)
  - Not quite as expressive as premium APIs
- **Integration**: 
  ```bash
  echo "Your digest content" | piper --model en_US-lessac-medium.onnx --output_file digest.mp3
  ```

### 2. **macOS say Command**
- **Cost**: FREE (built-in)
- **Quality**: ⭐⭐ Basic (functional but robotic)
- **Setup**: None (pre-installed)
- **Platform**: macOS only
- **Automation**: CLI, easily scripted
- **Pros**: 
  - Zero setup required
  - Native macOS integration
  - Multiple built-in voices
- **Cons**: 
  - Quality is noticeably robotic
  - Limited voice options
  - No neural/AI voices
- **Integration**: 
  ```bash
  say -v Samantha -o digest.aiff "Your digest content"
  ```

### 3. **ElevenLabs Free Tier**
- **Cost**: FREE tier: 10,000 characters/month (~10 min audio)
- **Quality**: ⭐⭐⭐⭐⭐ Excellent (best-in-class natural voices)
- **Setup**: Easy (API key signup)
- **Platform**: API-based (any platform)
- **Automation**: REST API or Python SDK
- **Pros**: 
  - Exceptional voice quality
  - Voice cloning available (paid)
  - Multiple languages
- **Cons**: 
  - 10K char limit is very restrictive for daily digest
  - Paid tier starts at $5/month for 30K chars
  - Requires internet, API dependency
  - Could exceed limits quickly with daily content
- **Integration**: Python SDK or curl to API

### 4. **OpenAI TTS API**
- **Cost**: $0.015 per 1,000 characters (~$0.018/minute)
- **Quality**: ⭐⭐⭐⭐⭐ Excellent (natural, expressive)
- **Setup**: Easy (API key)
- **Platform**: API-based
- **Automation**: REST API
- **Pros**: 
  - High quality voices (alloy, echo, fable, etc.)
  - Fast, reliable API
  - Good for moderate usage
- **Cons**: 
  - Not free - costs add up (~$1-3/month for daily digest)
  - Requires internet connection
  - Rate limits apply
- **Cost Estimate**: Daily 5-min digest ≈ $2-4/month

### 5. **Coqui TTS**
- **Cost**: FREE (open source)
- **Quality**: ⭐⭐⭐⭐ Good (varies by model)
- **Setup**: Hard (Python environment, dependencies)
- **Platform**: macOS, Linux, Windows
- **Automation**: Python scripts
- **Pros**: 
  - Free and open source
  - Multiple voice models available
  - Voice cloning capability
- **Cons**: 
  - Complex setup (conda/pip, GPU recommended)
  - Heavier resource usage than Piper
  - Project maintenance has slowed (team laid off)
- **Integration**: Python script with TTS library

### 6. **Google Cloud TTS**
- **Cost**: FREE tier: 1M characters/month (WaveNet), then $4 per 1M
- **Quality**: ⭐⭐⭐⭐ Very good (WaveNet voices)
- **Setup**: Medium (GCP account, API setup)
- **Platform**: API-based
- **Automation**: REST API or SDK
- **Pros**: 
  - Generous free tier
  - Multiple voice options
  - Reliable infrastructure
- **Cons**: 
  - Requires GCP account
  - API complexity
  - Privacy concerns (sends text to cloud)
- **Integration**: gcloud CLI or API calls

### 7. **Amazon Polly**
- **Cost**: FREE tier: 5M characters/month for 12 months, then ~$4 per 1M
- **Quality**: ⭐⭐⭐⭐ Good (Neural voices available)
- **Setup**: Medium (AWS account)
- **Platform**: API-based
- **Automation**: AWS CLI or SDK
- **Pros**: 
  - Generous free tier initially
  - Neural voices sound natural
- **Cons**: 
  - Requires AWS account
  - Complexity of AWS ecosystem
- **Integration**: AWS CLI or boto3

---

## Recommendation

**Primary Choice: Piper TTS**
- Best balance of quality, cost (free), and ease of automation
- Local processing means no privacy concerns
- No rate limits or API keys to manage
- Perfect for daily scheduled digest generation

**Alternative if quality is paramount: OpenAI TTS**
- Use if the ~$2-4/month cost is acceptable
- Slightly better voice quality
- Simpler than maintaining local models

**Avoid for this use case:**
- ElevenLabs free tier (too limiting for daily use)
- macOS say (quality too low for podcast format)
- Coqui (setup complexity not worth it vs Piper)

---

## Suggested Integration Workflow

```bash
#!/bin/bash
# Daily Digest TTS Script

# 1. Fetch or read markdown content
CONTENT=$(cat digest.md)

# 2. Convert markdown to plain text (strip formatting)
PLAIN_TEXT=$(echo "$CONTENT" | pandoc -f markdown -t plain)

# 3. Generate audio with Piper
piper \
  --model ~/.local/share/piper/en_US-lessac-medium.onnx \
  --output_file "digest_$(date +%Y-%m-%d).mp3" \
  <<< "$PLAIN_TEXT"

# 4. Optional: Upload to podcast host or serve locally
```

---

## Voice Model Recommendations for Piper

| Voice | Style | Best For |
|-------|-------|----------|
| lessac | Neutral, clear | News/digest content |
| libritts | Natural, varied | Long-form content |
| ljspeech | Classic TTS | Short announcements |