🎙️ AI Voice Generator

Transform text into high-quality speech using multiple AI-powered TTS services with an intuitive ChatGPT-inspired interface.

AI Voice Generator is a production-ready web application that converts text to speech using multiple TTS providers including OpenAI, ElevenLabs, Google Cloud, and Gemini. Features intelligent text optimization, advanced voice controls, persistent history, and a sleek dark-themed interface.

📋 Table of Contents

• ✨ Key Features
• 🚀 Quick Start
• 📦 Installation
• ⚙️ Configuration
• 🎯 Usage Guide
• 🧪 Testing
• 🏗️ Architecture
• 🔧 API Reference
• 🎨 Customization
• 📊 Performance
• 🔒 Security
• 🤝 Contributing
• 📄 License
• 📚 Documentation

✨ Key Features

🎤 Multi-Provider TTS Support

• OpenAI: High-quality voices with speed control (tts-1, tts-1-hd)
• ElevenLabs: Premium voices with advanced settings (stability, similarity, style)
• Google Cloud: 200+ voices in 40+ languages
• Gemini: Preview TTS with unique voice options

🧠 Intelligent Text Enhancement

• AI-powered optimization using OpenAI GPT or Gemini
• Multiple enhancement modes: Default, Shorter, Longer, Retry
• TTS-focused improvements: Grammar, flow, conversational tone
• Basic optimization for all services (abbreviation expansion, formatting)

🎛️ Advanced Voice Controls

• Service-specific settings: Speed (OpenAI), Voice parameters (ElevenLabs)
• Real-time parameter adjustment with instant feedback
• Voice search and filtering across all providers
• Dynamic voice loading based on service availability

🎭 Emotion-Aware TTS

• Intelligent emotion detection from text content
• 7 emotion types: Joy, Sadness, Anger, Fear, Surprise, Calm, Neutral
• Context-sensitive voice modulation based on detected emotion
• Confidence scoring with manual override options
• Auto-analysis with real-time text processing

📡 Real-Time Streaming

• Chunk-based audio generation for long texts
• Live progress tracking with detailed status updates
• Streaming-optimized for OpenAI TTS services
• Cancellable operations with real-time feedback
• Enhanced UX for processing large content

💾 Persistent Data Management

• SQLite database for reliable history storage
• Automatic file management in organized outputs directory
• Server-side audio storage with secure file serving
• Comprehensive generation metadata tracking

🎨 Premium User Experience

• ChatGPT-inspired dark theme with Tailwind CSS
• Responsive design for desktop and mobile
• Auto-playing history with visual indicators
• Real-time status updates and notifications
• Drag-and-drop file support for text input

🔧 Developer-Friendly

• Comprehensive test suite (unit, integration, performance)
• Provider pattern architecture for easy service addition
• RESTful API design with clear documentation
• Environment-based configuration with sample files
• Extensive error handling and logging

🚀 Quick Start

📦 Installation from PyPI (Recommended)

# Install from PyPI
pip install aivoicegen

# Run the application
aivoicegen

# Or run directly with Python
python -m aivoicegen

🛠️ Development Installation

Prerequisites

• Python 3.8+
• Git
• FFmpeg (for audio processing)

Setup

# Clone the repository
git clone https://github.com/yourusername/aivoicegen.git
cd aivoicegen

# Set up virtual environment
python -m venv venv
source venv/bin/activate  # Windows: venv\Scripts\activate

# Install in development mode
pip install -e .

# Configure environment
cp .env.sample .env
# Edit .env with your API keys

# Run the application
aivoicegen

Visit http://127.0.0.1:5000 and start generating speech! 🎉

📦 Installation

System Requirements

Component	Minimum	Recommended
Python	3.8+	3.11+
RAM	512MB	2GB+
Storage	1GB	5GB+
Network	Basic	Broadband

Detailed Installation

1. Clone Repository

git clone https://github.com/yourusername/aivoicegen.git
cd aivoicegen

2. Virtual Environment

# Create environment
python -m venv venv

# Activate (choose your platform)
source venv/bin/activate          # macOS/Linux
venv\Scripts\activate             # Windows
conda activate venv               # Conda

3. Install Dependencies

# Core dependencies
pip install -r requirements.txt

# Development dependencies (optional)
pip install -r requirements-dev.txt

4. Install FFmpeg

macOS:

brew install ffmpeg

Ubuntu/Debian:

sudo apt update && sudo apt install ffmpeg

Windows:

1. Download from FFmpeg website
2. Extract to C:\ffmpeg
3. Add C:\ffmpeg\bin to PATH

Verify installation:

ffmpeg -version

⚙️ Configuration

Quick Setup with Config Command (Recommended)

The easiest way to configure AIVoiceGen is using the built-in config system:

# Interactive setup - will guide you through API key configuration
aivoicegen config init

# Set individual API keys
aivoicegen config set --key OPENAI_API_KEY
aivoicegen config set --key ELEVENLABS_API_KEY

# View current configuration
aivoicegen config list

# Get specific configuration value
aivoicegen config get --key OPENAI_API_KEY

Configuration Features:

• 📁 Centralized storage: Config saved to ~/.aivoicegen/config.json
• 🔒 Secure input: API keys hidden during entry
• 📥 Smart defaults: Audio files saved to Downloads/AIVoiceGen
• 🔄 Fallback support: Environment variables still work

Manual Environment Setup

Alternatively, you can still use environment variables:

# Create .env file (development only)
cp .env.sample .env

API Provider Configuration

🤖 OpenAI Configuration

OPENAI_API_KEY=sk-your-openai-api-key-here

Features:

• 6 high-quality voices (alloy, echo, fable, onyx, nova, shimmer)
• 2 models (tts-1 for speed, tts-1-hd for quality)
• Speed control (0.25x - 4x)
• Text optimization with GPT

Setup:

1. Visit OpenAI Platform
2. Create API key
3. Add to .env file

Pricing: ~$0.015 per 1K characters

🎭 ElevenLabs Configuration

ELEVENLABS_API_KEY=your-elevenlabs-api-key-here

Features:

• Premium voice cloning
• Advanced voice controls (stability, similarity, style)
• Multilingual support
• Custom voice training

Setup:

1. Visit ElevenLabs
2. Get API key from profile
3. Add to .env file

Pricing: Freemium model, paid plans available

☁️ Google Cloud Configuration

GOOGLE_APPLICATION_CREDENTIALS=/path/to/service-account.json

Features:

• 200+ voices in 40+ languages
• WaveNet, Neural2, and Standard voices
• SSML support
• High-quality synthesis

Setup:

1. Create Google Cloud Project
2. Enable Text-to-Speech API
3. Create service account with TTS permissions
4. Download JSON key file
5. Set path in .env

Pricing: $4 per 1M characters (1M free/month)

💎 Gemini Configuration

GEMINI_API_KEY=your-gemini-api-key-here

Features:

• Preview TTS service
• Unique voice options (Kore, Puck, Charon, Fenrir, Aoede)
• Text optimization with Gemini Pro
• Integration with Google AI ecosystem

Setup:

1. Visit Google AI Studio
2. Generate API key
3. Add to .env file

Status: Preview (subject to changes)

Optional Configuration

# Application settings
FLASK_ENV=development
FLASK_DEBUG=true
PORT=5000

# Database
DATABASE_PATH=./history.db

# Cache settings
MAX_CACHE_SIZE=100

# Storage
OUTPUTS_DIR=outputs

# Security
SECRET_KEY=your-secret-key-here

🎯 Usage Guide

Basic Workflow

1. Enter Text: Type or upload your content
2. Enhance (Optional): Use AI to optimize text for speech
3. Configure Voice: Select service and voice options
4. Adjust Settings: Fine-tune voice parameters
5. Generate: Create high-quality speech
6. Review History: Access previous generations

Text Enhancement Modes

Mode	Purpose	Best For
Default	Balanced enhancement	General use
Shorter	Concise version (50-70% length)	Quick summaries
Longer	Expanded version (130-150% length)	Detailed narration
Retry	Alternative enhancement	Finding better phrasing

Advanced Voice Settings

OpenAI Settings

• Speech Speed: 0.25x (very slow) to 4x (very fast)
• Model Selection: tts-1 (fast) vs tts-1-hd (high quality)

ElevenLabs Settings

• Stability: 0-1 (consistent vs varied delivery)
• Similarity Boost: 0-1 (voice matching strength)
• Style: 0-1 (expressive vs neutral)
• Speaker Boost: Enable for clarity improvement

File Management

• Auto-save: All generated audio saved to outputs/ directory
• Persistent History: SQLite database tracks all generations
• Organized Storage: Files named with timestamps and service info
• Easy Access: Direct play/download from history sidebar

🧪 Testing

Test Suite Overview

Our comprehensive test suite ensures reliability and performance:

# Run all tests
python -m unittest discover tests

# Run specific test categories
python tests/test_app.py           # Core functionality
python tests/test_integration.py   # End-to-end workflows
python tests/test_performance.py   # Performance benchmarks

# Run with verbose output
python -m unittest discover tests -v

Test Categories

Unit Tests (test_app.py)

• ✅ TTS provider functionality
• ✅ Text optimization algorithms
• ✅ Database operations
• ✅ API endpoint validation
• ✅ Error handling
• ✅ Configuration management

Integration Tests (test_integration.py)

• ✅ End-to-end workflows
• ✅ Service integration
• ✅ Data persistence
• ✅ Concurrent operations
• ✅ Error recovery

Performance Tests (test_performance.py)

• ✅ Response time benchmarks
• ✅ Memory usage monitoring
• ✅ Scalability testing
• ✅ Cache effectiveness
• ✅ Database performance

Continuous Integration

# Example GitHub Actions workflow
name: Tests
on: [push, pull_request]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Set up Python
        uses: actions/setup-python@v2
        with:
          python-version: 3.11
      - name: Install dependencies
        run: |
          pip install -r requirements.txt
          sudo apt-get install ffmpeg
      - name: Run tests
        run: python -m unittest discover tests

🏗️ Architecture

System Overview

┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   Frontend      │    │   Flask API     │    │   TTS Services  │
│   (HTML/JS)     │◄──►│   (Python)      │◄──►│   (OpenAI, etc) │
└─────────────────┘    └─────────────────┘    └─────────────────┘
         │                       │                       │
         ▼                       ▼                       ▼
┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   Browser       │    │   SQLite DB     │    │   File System   │
│   Storage       │    │   (History)     │    │   (Audio Files) │
└─────────────────┘    └─────────────────┘    └─────────────────┘

Provider Pattern

Each TTS service implements a consistent interface:

class TTSProvider:
    def __init__(self):
        """Initialize with API credentials"""
        
    def list_voices(self) -> List[Dict]:
        """Return available voices"""
        
    def generate_speech(self, text: str, title: str, options: Dict) -> Tuple[bytes, str]:
        """Generate audio and return (content, filename)"""

Key Components

Backend (Flask)

• Provider Management: Dynamic service loading and configuration
• API Endpoints: RESTful design with comprehensive error handling
• Database Layer: SQLite with connection pooling and transactions
• File Management: Organized storage with secure serving
• Caching System: In-memory LRU cache for performance

Frontend (Vanilla JS + Tailwind)

• Responsive Design: Mobile-first approach with dark theme
• Real-time Updates: Dynamic service/voice loading
• State Management: Local state with server synchronization
• User Experience: Intuitive controls with immediate feedback

Data Layer

• SQLite Database: Lightweight, serverless, ACID-compliant
• File System: Organized audio storage with metadata
• Caching: Multi-level caching strategy
• Configuration: Environment-based with validation

Database Schema

CREATE TABLE generation_history (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    title TEXT NOT NULL,
    service TEXT NOT NULL,
    voice TEXT NOT NULL,
    text_snippet TEXT,
    filename TEXT,
    timestamp DATETIME DEFAULT CURRENT_TIMESTAMP,
    file_path TEXT
);

🔧 API Reference

Endpoints Overview

Endpoint	Method	Purpose	Authentication
/	GET	Serve frontend	None
/services	GET	List available TTS services	None
/voices/<service>	GET	Get voices for service	None
/generate	POST	Generate speech	None
/generate-stream	POST	Generate speech with streaming	None
/analyze-emotion	POST	Analyze text emotion	None
/optimize	POST	Enhance text	None
/history	GET	Get generation history	None
/outputs/<filename>	GET	Serve audio files	None
/api-config	GET/POST	Manage API configuration	None

Detailed API Documentation

Generate Speech

POST /generate
Content-Type: application/json

{
  "service": "openai",
  "title": "My Audio",
  "text": "Hello, world!",
  "voice_model_options": {
    "api_params": {
      "voice": "alloy",
      "model": "tts-1"
    },
    "speed": 1.0
  }
}

Response:

200 OK
Content-Type: audio/mp3
Content-Disposition: attachment; filename="My_Audio_openai_20231201123456.mp3"

[Binary audio data]

Optimize Text

POST /optimize
Content-Type: application/json

{
  "text": "This is a test about AI",
  "service": "openai",
  "mode": "default"
}

Response:

{
  "optimized_text": "Here's a test story about artificial intelligence and its fascinating applications."
}

Get Services

GET /services

Response:

{
  "openai": {
    "label": "OpenAI",
    "configured": true,
    "voices_endpoint": "/voices/openai",
    "voice_type": "static",
    "unavailable_reason": null
  },
  "elevenlabs": {
    "label": "ElevenLabs",
    "configured": false,
    "unavailable_reason": "API key not configured"
  }
}

Streaming Speech Generation

POST /generate-stream
Content-Type: application/json

{
  "service": "openai",
  "title": "My Project",
  "text": "Long text content for streaming generation...",
  "voice_model_options": {
    "api_params": {"voice": "alloy", "model": "tts-1"},
    "speed": 1.0
  }
}

Response: Text stream with JSON objects

{"type": "status", "message": "Processing 3 text chunks...", "progress": 0, "total_chunks": 3}
{"type": "status", "message": "Generating audio for chunk 1/3...", "progress": 20}
{"type": "chunk_complete", "chunk_index": 0, "message": "Chunk 1/3 completed"}
{"type": "complete", "filename": "audio_file.mp3", "message": "Speech generated successfully!"}

Emotion Analysis

POST /analyze-emotion
Content-Type: application/json

{
  "text": "I'm so excited about this amazing opportunity!",
  "service": "openai",
  "voice_model_options": {
    "api_params": {"voice": "alloy"},
    "speed": 1.0
  }
}

Response:

{
  "emotion": "joy",
  "confidence": 0.95,
  "original_params": {
    "api_params": {"voice": "alloy"},
    "speed": 1.0
  },
  "suggested_params": {
    "api_params": {"voice": "alloy"},
    "speed": 1.1
  },
  "emotion_description": "Positive, upbeat, and energetic tone"
}

🎨 Customization

Theming

The application uses a ChatGPT-inspired dark theme built with Tailwind CSS:

/* Custom color palette */
:root {
  --gpt-dark: #202123;
  --gpt-dark-secondary: #343541;
  --gpt-dark-tertiary: #40414F;
  --gpt-accent: #10A37F;
  --gpt-light-gray: #D1D5DB;
}

Adding TTS Providers

1. Create Provider Class:

class NewTTSProvider:
    def __init__(self):
        # Initialize with API credentials
        pass
    
    def list_voices(self):
        # Return voice list
        return []
    
    def generate_speech(self, text, title, options):
        # Generate audio
        return audio_bytes, filename

2. Register Provider:

TTS_PROVIDERS_CONFIG["new_service"] = {
    "instance": new_provider_instance,
    "label": "New Service",
    "voice_type": "dynamic"
}

3. Add Frontend Support:

// Add service-specific controls
case 'new_service':
    showNewServiceControls();
    break;

Environment Customization

# Custom branding
APP_NAME=My Voice Generator
APP_LOGO=/path/to/logo.png

# Feature flags
ENABLE_FILE_UPLOAD=true
ENABLE_HISTORY=true
ENABLE_OPTIMIZATION=true

# Performance tuning
MAX_TEXT_LENGTH=10000
MAX_CACHE_SIZE=500
CACHE_TTL=3600

📊 Performance

Benchmarks

Operation	Average Time	95th Percentile
Page Load	150ms	300ms
Service List	50ms	100ms
Voice List	200ms	500ms
Text Optimization	800ms	2000ms
Audio Generation	2-5s	10s

Optimization Features

Caching Strategy

• In-memory LRU cache for TTS results
• Browser caching for static assets
• Service response caching for voice lists
• Database query optimization with proper indexing

Performance Monitoring

# Built-in performance logging
@app.before_request
def log_request_info():
    app.logger.info('Request: %s %s', request.method, request.url)

@app.after_request
def log_response_info(response):
    app.logger.info('Response: %s', response.status_code)
    return response

Scalability Considerations

• Stateless design for horizontal scaling
• Database connection pooling for concurrent requests
• Async processing potential for background tasks
• CDN integration ready for static assets

Resource Usage

Component	CPU Usage	Memory Usage	Storage
Flask App	Low	50-200MB	Minimal
SQLite DB	Minimal	10-50MB	Growing
Audio Files	None	None	1-10MB/file
Cache	Low	10-100MB	Temporary

🔒 Security

Security Features

API Security

• Input validation on all endpoints
• SQL injection prevention with parameterized queries
• File upload restrictions (type, size validation)
• Rate limiting capability (configurable)

Data Protection

• Environment variable isolation for API keys
• Secure file serving with path validation
• No credential logging in application logs
• Temporary file cleanup after processing

Best Practices

# Example security measures
@app.before_request
def security_headers():
    # CSRF protection
    if request.method == 'POST':
        validate_csrf_token(request)
    
    # File upload validation
    if 'file' in request.files:
        validate_file_upload(request.files['file'])

@app.after_request
def add_security_headers(response):
    response.headers['X-Content-Type-Options'] = 'nosniff'
    response.headers['X-Frame-Options'] = 'DENY'
    return response

Production Deployment

Environment Security

# Production .env example
FLASK_ENV=production
FLASK_DEBUG=false
SECRET_KEY=complex-random-string-here

# Use secrets management
OPENAI_API_KEY=${OPENAI_API_KEY}
ELEVENLABS_API_KEY=${ELEVENLABS_API_KEY}

Server Configuration

• HTTPS enforcement with SSL certificates
• Reverse proxy (nginx) for static file serving
• Process management with gunicorn/uwsgi
• Monitoring with application performance tools

Database Security

• Regular backups of SQLite database
• File permissions properly configured
• Database encryption at rest (if required)
• Access logging for audit trails

🤝 Contributing

We welcome contributions! Please follow our guidelines:

Development Setup

# Fork and clone repository
git clone https://github.com/yourusername/aivoicegen.git
cd aivoicegen

# Create feature branch
git checkout -b feature/amazing-feature

# Set up development environment
python -m venv venv
source venv/bin/activate
pip install -r requirements.txt
pip install -r requirements-dev.txt

# Run tests
python -m unittest discover tests

# Start development server
python app.py

Contribution Types

• 🐛 Bug Reports: Use GitHub issues with detailed descriptions
• ✨ Feature Requests: Propose new functionality with use cases
• 📖 Documentation: Improve README, API docs, or code comments
• 🧪 Tests: Add test coverage for existing or new functionality
• 🎨 UI/UX: Enhance the user interface and experience
• 🔧 Performance: Optimize code for better performance

Code Standards

• Python: Follow PEP 8 style guide
• JavaScript: Use ES6+ features consistently
• HTML/CSS: Semantic markup with Tailwind classes
• Documentation: Clear docstrings and comments
• Testing: Maintain 80%+ test coverage

Pull Request Process

1. Create descriptive PR title and detailed description
2. Reference related issues with closing keywords
3. Ensure all tests pass before requesting review
4. Add tests for new functionality
5. Update documentation as needed
6. Follow security guidelines for sensitive changes

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

MIT License Summary

• ✅ Commercial use allowed
• ✅ Modification allowed
• ✅ Distribution allowed
• ✅ Private use allowed
• ❌ Liability not provided
• ❌ Warranty not provided

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📚 Documentation

Additional documentation is available in the docs/ directory:

Document	Description
todolist.md	Development tasks organized by priority
secrets.md	Environment variables and API setup guide
PRD.md	Product Requirements Document with user stories
design.md	System architecture and enhancement roadmap

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